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  • 1.
    Arakelyan, Arsen
    et al.
    Institute of Molecular Biology, National Academy of Sciences of the Republic of Armenia (NAS RA), Yerevan, Armenia.
    Zakharyan, Roksana
    Institute of Molecular Biology, National Academy of Sciences of the Republic of Armenia (NAS RA), Yerevan, Armenia.
    Hambardzumyan, Marina
    Högskolan i Halmstad, Akademin för ekonomi, teknik och naturvetenskap, Bio- och miljösystemforskning (BLESS).
    Petrkova, Jana
    Laboratory of Immunogenomics and Immunoproteomics, Institute of Molecular and Translational Medicine, Medical Faculty of Palacky University, Olomouc, Czech Republic.
    Olsson, M. Charlotte
    Högskolan i Halmstad, Akademin för ekonomi, teknik och naturvetenskap, Bio- och miljösystemforskning (BLESS), Biomekanik och biomedicin.
    Petrek, Martin
    Laboratory of Immunogenomics and Immunoproteomics, Institute of Molecular and Translational Medicine, Medical Faculty of Palacky University, Olomouc, Czech Republic.
    Boyajyan, Anna
    Institute of Molecular Biology, National Academy of Sciences of the Republic of Armenia (NAS RA), Yerevan, Armenia.
    Functional Genetic Polymorphisms of Monocyte Chemoattractant Protein 1 and C-C Chemokine Receptor Type 2 in Ischemic Stroke2014Inngår i: Journal of Interferon and Cytokine Research, ISSN 1079-9907, E-ISSN 1557-7465, Vol. 34, nr 2, s. 100-105Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Recent findings indicated that monocyte chemoattractant protein 1 (MCP1) and its C-C chemokine receptor type 2 (CCR2) play a key role in ischemic stroke (IS) progression. This study was aimed at evaluating the potential association of the MCP1 gene (MCP1) rs1024611 (-2518 A>G) and CCR2 gene (CCR2) rs1799864 (V64I; 190 G>A) functional single nucleotide polymorphisms (SNPs) with IS in the Armenian population. For the purpose of this study, genomic DNA samples of 100 patients with the first-episode IS and 115 healthy subjects (controls) were genotyped for the selected SNPs using a polymerase chain reaction with sequence-specific primers. The results obtained demonstrated that while the CCR2 rs1799864 SNP genotypes were equally distributed among patients and controls, the frequency and carriage rate of the of the MCP1 rs1024611*G minor allele were higher in patients. While a potential association between IS and CCR2 rs1799864 SNP was evaluated for the first time, the latest finding was in agreement with the earlier data reported for some other populations. In summary, this study revealed no association of CCR2 rs1799864 SNP with IS, and a positive association between G minor allele of MCP1 rs1024611 SNP and IS in the Armenian population. Based on the present and earlier reported data, we concluded that the minor G allele of the MCP1 rs1024611 SNP might be considered a risk factor for IS.

  • 2.
    Brorsson, Sofia
    et al.
    Högskolan i Halmstad, Sektionen för ekonomi och teknik (SET), Bio- och miljösystemforskning (BLESS), Biomekanik och biomedicin.
    Lundgren, Lina
    Högskolan i Halmstad, Sektionen för ekonomi och teknik (SET), Bio- och miljösystemforskning (BLESS).
    Olsson, Charlotte
    Högskolan i Halmstad, Sektionen för ekonomi och teknik (SET), Bio- och miljösystemforskning (BLESS).
    Ett fysiologiskt perspektiv på fysisk aktivitet och hälsa2010Inngår i: Hälsa & Livsstil: forskning och praktiska tillämpningar / [ed] Lillemor R-M Hallberg, Lund: Studentlitteratur, 2010, 1, s. 87-112Kapittel i bok, del av antologi (Annet vitenskapelig)
  • 3.
    Brorsson, Sofia
    et al.
    Högskolan i Halmstad, Sektionen för ekonomi och teknik (SET), Bio- och miljösystemforskning (BLESS), Biomekanik och biomedicin.
    Olsson, M Charlotte
    Högskolan i Halmstad, Sektionen för ekonomi och teknik (SET), Bio- och miljösystemforskning (BLESS), Biomekanik och biomedicin.
    Bengtsson, Oscar
    Petersson, Johan
    Maximal strength in one leg squat correlates with acceleration capacity and agility2010Konferansepaper (Fagfellevurdert)
    Abstract [en]

    INTRODUCTION: In many intermittent team sports capacities such as speed, agility and explosiveness are important for performance and are evaluated by sprint-, agility- and strength tests. Earlier studies have shown strong correlations between strength in the two leg squat exercise and sprint performance in various distances but not in sprint performance in agility. Studies evaluating squat strength predominantly perform tests on two legs even when they test athletes involved in intermittent sports where sprinting and agility are common features. Thus, the purpose of this study was to investigate the correlation between maximal strength in a one leg squat (Bulgarian split squat) and acceleration capacity in various sprint distances and agility.

    METHODS: The test group consisted of 19 men (mean age 24 ± 2 years ) with experience in intermittent team sports. Acceleration capacity was assessed by sprint tests at 5, 10 and 20 meters and agility was evaluated using the zigzag agility test. The timing was made using photocells (Muscle lab,Ergotest Technology,Norway). The Bulgarian split squat was performed in a smith machine with the barbell on the shoulders to a depth of 110 degrees between tibia and femur.

    RESULTS: The results show significant correlation between maximal strength in the Bulgarian split squat and sprint capacity in the 5 and 10 meter sprint test (Rp= -0,56; p<0.01) as well as the agility test. Maximal strength relative to bodyweight showed significant correlation with the 5 and 20 meter sprint (Rp=-0,62; p< 0,01) as well as the agility test. The zigzag agility test also showed significant correlation between all distances in the sprint tests (p<0.01).

    CONCLUSION: The results from this study show that there maximal strength in one leg correlate significantly with both acceleration capacity and agility. Implementing one leg exercises in the strength and conditioning routine can be useful for athletes in intermittent sports wanting to improve agility and short sprinting capacity. Further implications is that the Bulgarian split squat could be a more functional test for agility performance than the squat on two legs which  predominantly is being used today.

  • 4.
    Brorsson, Sofia
    et al.
    Högskolan i Halmstad, Sektionen för ekonomi och teknik (SET), Bio- och miljösystemforskning (BLESS), Biomekanik och biomedicin.
    Olsson, M Charlotte
    Högskolan i Halmstad, Sektionen för ekonomi och teknik (SET), Bio- och miljösystemforskning (BLESS), Biomekanik och biomedicin.
    Fredriksson, Daniel
    Training program for young female soccer players with focus on increasing the acceleration capacity2010Konferansepaper (Fagfellevurdert)
    Abstract [en]

    INTRODUCTION: Soccer is the world’s most popular team sport with over 240 million players around the world. About 20 million of the 240 million players are women and 80% of these women are adolescence or juniors. Acceleration capacity is one of the most important physical qualities for a soccer player. The aim of this study was to design, perform and evaluate a training program for young female soccer players with focus on increasing the acceleration capacity.

    METHODS: There were 22 young females (14,6 ± 1,0 years, 50,3 ± 5,1 kg, 160,2 ± 3,0 cm) from two different soccer teams participating. They were split into two groups, one test group (TG) (n=8) and one control group (CG) (n=14). The training period was 12 weeks, with soccer training 3 times per week for both groups. In the TG one workout per week was specifically designed to increase the acceleration capacity and took about 40 minutes to perform. The acceleration capacity was evaluated by a sprint test of 10-20-30 meter and vertical countermovement jump test using photocells.

    RESULTS: The TG showed a tendency to increased acceleration at the sprint test (p=0,08) and significant improvement at the jump test (p<0.05) after 12 weeks of training. The acceleration training also showed significant correlations between the sprint- and jump test in the TG after completed the 12 week training period (p<0.05). The CG showed decreased acceleration at the sprint test (p<0.05) and the vertical jump height was not significantly different. There were no significant differences between the two groups pre and post training.

    CONCLUSION: A 12 week training program can increase the acceleration capacity and the vertical jump height on young female soccer players. In sport were acceleration capacity is important it seems relevant to specifically train those qualities.

  • 5.
    Brorsson, Sofia
    et al.
    Högskolan i Halmstad, Sektionen för ekonomi och teknik (SET), Bio- och miljösystemforskning (BLESS), Biomekanik och biomedicin.
    Olsson, M Charlotte
    Högskolan i Halmstad, Sektionen för ekonomi och teknik (SET), Bio- och miljösystemforskning (BLESS), Biomekanik och biomedicin.
    Westerberg, Martin
    Maximal multiple repetitions in free weight strength training with different bar sizes2010Konferansepaper (Fagfellevurdert)
    Abstract [en]

    INTRODUCTION: An individual’s grip strength is vital for performance of physical demanding tasks such as give some other example here? As well as strength training with free weights. Performing strength training with a thicker grip around the bar may enhance the strength of the grip in the athlete without other special routines for grip strength development. The purpose of this study was a) to examine the difference in performance in multiple repetitions in two strength training exercises using two different sizes on the bar, b) to investigate correlations between hand grip strength and the amount of repetitions performed with two different sizes of the  bar and c) to correlate hand size with the amount of performed repetitions with two different bar sizes.

    METHODS: Fifteen male participants (24 ± 4 years) with at least one year of strength training experience performed bench press and a prone lying rowing exercise with two different bar sizes (normal Olympic lifting bar with and with out Fat Gripz™). The participants performed test of maximal number of repetitions at a level of 80% of one repetition maximum (1RM), hand size was measured as well as maximum grip strength (using JAMAR).

    RESULTS: The use of a thicker diameter bar resulted in 22 % (p<0.01) reduction of weight performance in number of performed repetitions in the bench press compared to the normal diameter of the bar.  When performing lying bench row a 66 % (p<0.01) reduction in number of performed repetitions was seen with the thicker diameter of the bar. There was no significant correlation between hand size and the submaximal strength test (rp = 0,33 ; p = 0,23) or grip strength and submaximal strength test (rp = 0,31 ; p = 0,27).

    CONCLUSION: The results from this study indicated that the size of the bar diameter influences the performance in maximal number of repetitions in a prone lying rowing exercise and bench press.  Further studies have to be done to analyses the effect of strength training with thicker bar.

     

  • 6.
    Frandsen, Björn
    et al.
    Högskolan i Halmstad, Akademin för ekonomi, teknik och naturvetenskap, Bio- och miljösystemforskning (BLESS).
    Olsson, M Charlotte
    Högskolan i Halmstad, Akademin för ekonomi, teknik och naturvetenskap, Bio- och miljösystemforskning (BLESS), Biomekanik och biomedicin.
    Hip and Trunk Muscle Electromyography Differences Between Bilateral and Unilateral Bodyweight Resistance Exercises2015Konferansepaper (Annet vitenskapelig)
    Abstract [en]

    Introduction

    In sports, force production and movement are predominantly generated in a unilateral weight-bearing stance. Therefore, unilateral resistance training may possibly elicit more sport-specific strength gains compared to traditional bilateral strength training. Hip- and trunk- muscles stabilize the pelvis and trunk to maintain proper technique and posture in resistance training and are thought to play a central role in sports performance as well as injury prevention. Hip- and trunk- muscle activity increases as the body weight balance change from a bilateral to a unilateral stance. Little research has examined the magnitude of change in muscle activation differences between bilateral and unilateral stance in lower body exercises.

    Aim

    The aim of this study was to examine the electromyographic (EMG) activity in hip and trunk muscles in three bodyweight exercises performed in a bilateral and a unilateral stance.

    Methods

    14 healthy, young adults participated in a single session, single-group, observational study. Manual muscle testing was used to attain a maximal voluntary isometric contraction (MVC) value for gluteus medius, gluteus maximus, rectus abdominis, and erector spinae. EMG measurements (4 channel ME6000, MegaWin Software, Kuopio, Finland) were taken during performance of squat, bridge, and plank exercises in both a bilateral and a unilateral stance.

    Results

    In all three exercises, EMG activity (presented as magnitude of change) was greater in the unilateral stance compared to the bilateral stance (p< 0.05), for the muscles gluteus medius (squat 478%, bridge 204%, plank 285%) and gluteus maximus (squat 371%, bridge 172%, plank 233%). In addition, in plank, EMG activity was greater in unilateral stance compared to the bilateral stance (p< 0.05) in rectus abdominis (120%) and erector spinae (127%). In the squat and bridge, no differences were identified in EMG activity for rectus abdominis and erector spinae between the bilateral and the unilateral stance.

    Discussion

    Nearly all unilateral exercises activated the hip muscles (gluteus medius, gluteus maximus) more than double compared to the same exercises performed bilaterally. In particular, gluteal muscle activity during the unilateral squat was more than 3.5 fold greater as compared to the bilateral stance. This greater magnitude of change in the unilateral squat might be explained by the single contact point with the ground in the squat, whereas the bridge and plank exercises include more ground contact points even in their unilateral stance. A unilateral training program including squat exercises might be beneficial for developing hip strength which is of great importance in sports performance.

  • 7.
    Helland, Christian
    et al.
    The Norwegian Olympic and Paralympic Committee and Confederation of Sports, Oslo, Norway.
    Hole, Eirik
    The Norwegian Olympic and Paralympic Committee and Confederation of Sports, Oslo, Norway.
    Iversen, Erik
    The Norwegian Olympic and Paralympic Committee and Confederation of Sports, Oslo, Norway.
    Olsson, Monica Charlotte
    Högskolan i Halmstad, Akademin för ekonomi, teknik och naturvetenskap, Rydberglaboratoriet för tillämpad naturvetenskap (RLAS).
    Seynnes, Olivier
    Norwegian School of Sport Sciences, Oslo, Norway.
    Solberg, Paul Andre
    Defense Institute, Norwegian School of Sport Sciences, Oslo, Norway.
    Paulsen, Gøran
    The Norwegian Olympic and Paralympic Committee and Confederation of Sports, Oslo, Norway & Norwegian School of Sport Sciences, Oslo, Norway.
    Training Strategies to Improve Muscle Power: Is Olympic-style Weightlifting Relevant?2017Inngår i: Medicine & Science in Sports & Exercise, ISSN 0195-9131, E-ISSN 1530-0315, Vol. 49, nr 4, s. 736-745Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    INTRODUCTION: This efficacy study investigated the effects of (1) Olympic-style weightlifting (OWL), (2) motorized strength and power training (MSPT), and (3) free weight strength and power training (FSPT) on muscle power.

    METHODS: Thirty-nine young athletes (20±3 yr.; ice hockey, volleyball and badminton) were randomized into the three training groups. All groups participated in 2-3 sessions/week for 8 weeks. The MSPT and FSPT groups trained using squats (two legs and single leg) with high force and high power, while the OWL group trained using clean and snatch exercises. MSPT was conducted as slow-speed isokinetic strength training and isotonic power training with augmented eccentric load, controlled by a computerized robotic engine system. FSPT used free weights. The training volume (sum of repetitions x kg) was similar between all three groups. Vertical jumping capabilities were assessed by countermovement jump (CMJ), squat jump (SJ), drop jump (DJ), and loaded CMJs (10-80 kg). Sprinting capacity was assessed in a 30 m sprint. Secondary variables were squat 1-repetition-maximum, body composition and quadriceps thickness and architecture.

    RESULTS: OWL resulted in trivial improvements, and inferior gains compared to FSPT and MSPT for CMJ, SJ, and DJ. MSPT demonstrated small, but robust effects on SJ, DJ and loaded CMJs (3-12%). MSPT was superior to FSPT in improving 30 m sprint performance. FSPT and MSPT, but not OWL, demonstrated increased thickness in the vastus lateralis and rectus femoris (4-7%).

    CONCLUSION: MSPT was time-efficient and equally or more effective than FSPT training in improving vertical jumping and sprinting performance. OWL was generally ineffective and inferior to the two other interventions. Copyright © 2016 by the American College of Sports Medicine.

  • 8.
    Horwath, Oscar
    et al.
    Högskolan i Halmstad, Akademin för ekonomi, teknik och naturvetenskap.
    Paulsen, Gøran
    The Norwegian Olympic and Paralympic Committee and Confederation of Sports, Oslo, Norway & Department of Physical Performance, Norwegian School of Sport Sciences, Oslo, Norway.
    Esping, Tobias
    Högskolan i Halmstad, Akademin för ekonomi, teknik och naturvetenskap.
    Seynnes, Olivier
    Department of Physical Performance, Norwegian School of Sport Sciences, Oslo, Norway.
    Olsson, M. Charlotte
    Högskolan i Halmstad, Akademin för ekonomi, teknik och naturvetenskap, Rydberglaboratoriet för tillämpad naturvetenskap (RLAS).
    Isokinetic resistance training combined with eccentric overload improves athletic performance and induces muscle hypertrophy in young ice hockey players.2019Inngår i: Journal of Science and Medicine in Sport, ISSN 1440-2440, E-ISSN 1878-1861, Vol. 22, nr 7, s. 821-826Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    OBJECTIVES: To determine the combined effects of slow isokinetic resistance training and eccentric overload and compare it to traditional resistance training on strength, power, body composition and muscle hypertrophy in young ice hockey players.

    DESIGN: Experimental, randomized trial.

    METHODS: Twenty-two resistance-trained ice hockey players (18±1year) were assigned to either isokinetic resistance training and eccentric overload (ISO/ECC; n=11) or traditional resistance training (TRAD; n=11). Participants underwent supervised progressive resistance training for 8 weeks (2-3 sessions/week) involving lower body multiple-joint exercises (heavy squats and explosive jump squats). The ISO/ECC group performed their training using a computerized robotic engine system (1080 Quantum synchro, Sweden), whereas the TRAD group performed the same resistance exercises with isotonic loading. Before and after the intervention, participants were evaluated in 1RM back squat, loaded jump squats, sprint- and jump performance, body composition and muscle thickness using ultrasound measurement.

    RESULTS: Similar moderate increases in 1RM back squat and power output in the jump squats were found in both the ISO/ECC and TRAD groups (11-17%, P<0.01), whereas only the ISO/ECC group showed improvements in drop jump performance (9.8%, P=0.01). Moreover, similar trivial changes in body composition were observed in both groups, while only the ISO/ECC training group increased muscle thickness in the vastus intermedius (P=0.01) and rectus femoris muscles (P=0.03).

    CONCLUSIONS: Both modalities effectively increased maximal strength and power output, whereas isokinetic resistance training, combined with eccentric overload, improved drop jump performance and induced greater muscle hypertrophy than traditional training in young ice hockey players. © 2019 Sports Medicine Australia

  • 9.
    Khan, Taha
    et al.
    Högskolan i Halmstad, Akademin för informationsteknologi, Halmstad Embedded and Intelligent Systems Research (EIS), CAISR Centrum för tillämpade intelligenta system (IS-lab).
    Lundgren, Lina
    Högskolan i Halmstad, Akademin för informationsteknologi, Halmstad Embedded and Intelligent Systems Research (EIS), CAISR Centrum för tillämpade intelligenta system (IS-lab). Högskolan i Halmstad, Akademin för ekonomi, teknik och naturvetenskap, Rydberglaboratoriet för tillämpad naturvetenskap (RLAS).
    Järpe, Eric
    Högskolan i Halmstad, Akademin för informationsteknologi, Halmstad Embedded and Intelligent Systems Research (EIS), CAISR Centrum för tillämpade intelligenta system (IS-lab).
    Olsson, M. Charlotte
    Högskolan i Halmstad, Akademin för ekonomi, teknik och naturvetenskap, Rydberglaboratoriet för tillämpad naturvetenskap (RLAS).
    Wiberg, Pelle
    Raytelligence AB, Halmstad, Sweden.
    A Novel Method for Classification of Running Fatigue Using Change-Point Segmentatio2019Inngår i: Sensors, ISSN 1424-8220, E-ISSN 1424-8220, Vol. 19, nr 21, artikkel-id 4729Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Blood lactate accumulation is a crucial fatigue indicator during sports training. Previous studies have predicted cycling fatigue using surface-electromyography (sEMG) to non-invasively estimate lactate concentration in blood. This study used sEMG to predict muscle fatigue while running and proposes a novel method for the automatic classification of running fatigue based on sEMG. Data were acquired from 12 runners during an incremental treadmill running-test using sEMG sensors placed on the vastus-lateralis, vastus-medialis, biceps-femoris, semitendinosus, and gastrocnemius muscles of the right and left legs. Blood lactate samples of each runner were collected every two minutes during the test. A change-point segmentation algorithm labeled each sample with a class of fatigue level as (1) aerobic, (2) anaerobic, or (3) recovery. Three separate random forest models were trained to classify fatigue using 36 frequency, 51 time-domain, and 36 time-event sEMG features. The models were optimized using a forward sequential feature elimination algorithm. Results showed that the random forest trained using distributive power frequency of the sEMG signal of the vastus-lateralis muscle alone could classify fatigue with high accuracy. Importantly for this feature, group-mean ranks were significantly different (p < 0.01) between fatigue classes. Findings support using this model for monitoring fatigue levels during running. © 2019 by the authors.

  • 10.
    Khan, Taha
    et al.
    Högskolan i Halmstad, Akademin för informationsteknologi, Halmstad Embedded and Intelligent Systems Research (EIS), CAISR Centrum för tillämpade intelligenta system (IS-lab).
    Lundgren, Lina
    Högskolan i Halmstad, Akademin för ekonomi, teknik och naturvetenskap, Rydberglaboratoriet för tillämpad naturvetenskap (RLAS). Högskolan i Halmstad, Akademin för informationsteknologi, Halmstad Embedded and Intelligent Systems Research (EIS), CAISR Centrum för tillämpade intelligenta system (IS-lab).
    Järpe, Eric
    Högskolan i Halmstad, Akademin för informationsteknologi, Halmstad Embedded and Intelligent Systems Research (EIS), CAISR Centrum för tillämpade intelligenta system (IS-lab).
    Olsson, M. Charlotte
    Högskolan i Halmstad, Akademin för ekonomi, teknik och naturvetenskap, Rydberglaboratoriet för tillämpad naturvetenskap (RLAS).
    Wiberg, Pelle
    Raytelligence AB, Halmstad, Sweden.
    A Novel Method for Classification of Running Fatigue Using Change-Point Segmentation2019Inngår i: Sensors, ISSN 1424-8220, E-ISSN 1424-8220, Vol. 19, nr 21, artikkel-id 4729Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Blood lactate accumulation is a crucial fatigue indicator during sports training. Previous studies have predicted cycling fatigue using surface-electromyography (sEMG) to non-invasively estimate lactate concentration in blood. This study used sEMG to predict muscle fatigue while running and proposes a novel method for the automatic classification of running fatigue based on sEMG. Data were acquired from 12 runners during an incremental treadmill running-test using sEMG sensors placed on the vastus-lateralis, vastus-medialis, biceps-femoris, semitendinosus, and gastrocnemius muscles of the right and left legs. Blood lactate samples of each runner were collected every two minutes during the test. A change-point segmentation algorithm labeled each sample with a class of fatigue level as (1) aerobic, (2) anaerobic, or (3) recovery. Three separate random forest models were trained to classify fatigue using 36 frequency, 51 time-domain, and 36 time-event sEMG features. The models were optimized using a forward sequential feature elimination algorithm. Results showed that the random forest trained using distributive power frequency of the sEMG signal of the vastus-lateralis muscle alone could classify fatigue with high accuracy. Importantly for this feature, group-mean ranks were significantly different (p < 0.01) between fatigue classes. Findings support using this model for monitoring fatigue levels during running. © 2019 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/).

  • 11.
    Kroos, G.
    et al.
    Dept. of Exercise and Sport Sciences, Univ. of Copenhagen, Copenhagen, Denmark.
    Hansen, A
    Dept. of Exercise and Sport Sciences, Univ. of Copenhagen, Copenhagen, Denmark.
    Hanskov, D J A
    Dept. of Exercise and Sport Sciences, Univ. of Copenhagen, Copenhagen, Denmark.
    Olsson, M Charlotte
    Dept. of Exercise and Sport Sciences, Univ. of Copenhagen, Copenhagen, Denmark.
    Olsen, K.
    Dept. of Exercise and Sport Sciences, Univ. of Copenhagen, Copenhagen, Denmark.
    Hellsten, Y.
    Dept. of Exercise and Sport Sciences, Univ. of Copenhagen, Copenhagen, Denmark.
    Gene expression of angiogenic factors in muscle tissue during age-related development of hypertension in spontaneously hypertensive rats2008Inngår i: Abstracts 25th Conference of the European Society for Microcirculation: Integrating Vascular Biology and Medicine: Basic and Clinical Science / [ed] Akos Koller, Basel: S. Karger, 2008, Vol. 45, s. 120-120Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Essential hypertension has been associated with capillary rarefaction but little is known about the cellular mechanisms underlying this process. We examined the gene expression of angiogenic factors during age-related development of hypertension in spontaneously hypertensive rats (SHR). Wild-type Wistar Kyoto (WKY) rats served as controls. White gastrocnemius muscle was obtained and blood pressure was monitored at 5, 10 and 15 weeks of age. In the SHR group, systolic blood pressure increased from 5 to 10 and 15 weeks of age and the levels were higher than in the WKY group at 10 and 15 weeks (~70%; P<0.05). The mRNA content for MMP-2 was overall lower (P<0.05) in SHR compared to WKY. VEGFmRNA increased (p<0.05) from 5 to 10 weeks in SHR and there was a general increase (P<0.05) in the VEGF receptor flt-1. There was a trend for a lower content of eNOS and CYP 2C11 in the SHR than in WKY group. There were no alterations in the mRNA content of KDR, AMP 5'- nucleotidase, or Cytochrome P450 4A. The results show that the age-related development of hypertension from 5 to 15 weeks in SHR rats is not associated with major changes in mRNA content of the herein included angiogenic factors.

  • 12.
    Larsson, Jonas
    et al.
    Högskolan i Halmstad, Akademin för ekonomi, teknik och naturvetenskap, Rydberglaboratoriet för tillämpad naturvetenskap (RLAS). Department of Medical Imaging and Physiology, Skåne University Hospital Department of Translational Medicine, Lund University, Lund, Sweden & Swedish Armed Forces, Eksjö, Sweden.
    Dencker, Magnus
    Department of Medical Imaging and Physiology, Skåne University Hospital Department of Translational Medicine, Lund University, Lund, Sweden.
    Olsson, M. Charlotte
    Högskolan i Halmstad, Akademin för ekonomi, teknik och naturvetenskap, Rydberglaboratoriet för tillämpad naturvetenskap (RLAS).
    Bremander, Ann
    Högskolan i Halmstad, Akademin för ekonomi, teknik och naturvetenskap, Rydberglaboratoriet för tillämpad naturvetenskap (RLAS). Department of Clinical Sciences, Section of Rheumatology, Lund University, Lund, Sweden.
    Development and application of a questionnaire to self-rate physical work demands for ground combat soldiers2020Inngår i: Applied Ergonomics, ISSN 0003-6870, E-ISSN 1872-9126, Vol. 83, artikkel-id 103002Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Purpose: The aim of the present study was to identify the most physically demanding work tasks for Swedish ground combat soldiers through the development and application of a questionnaire survey. This is the first in a series of studies aiming to describe the development process and validation of physical selection standards in the Swedish armed forces.

    Methods: Based on procedural documentation, combat manuals and job analyses, a questionnaire was developed that defined and rated the perceived physical strain of 30 work tasks for ground combat soldiers. To assess validity, an expert focus group was used and psychometric analysis performed. The questionnaire was then distributed to 231 ground combat soldiers, of whom 165 responded (71%).

    Results: The questionnaire was validated in three steps to achieve face and content validity, and internal consistency was acceptable (Chronbach's alpha ≥0.95). Of the 30 work tasks included in the survey, transport of wounded was rated as the most demanding task for both aerobic capacity and strength. Other highly demanding tasks for aerobic capacity included combat movement (low/high crawl), dismounted attack in close country, urban and rough terrain and carrying heavy loads. There were no gender differences for either aerobic or strength demands in the top five most challenging tasks based on proportions.

    Conclusions: This study identified the most physically demanding tasks performed in the Swedish ground combat forces. Almost all the physically demanding tasks found in the present study contain elements of lifting and carrying, which require muscular strength and muscular endurance, with no gender differences. © 2019 Elsevier Ltd. All rights reserved.

  • 13.
    Larsson, Jonas
    et al.
    Högskolan i Halmstad, Akademin för ekonomi, teknik och naturvetenskap, Rydberglaboratoriet för tillämpad naturvetenskap (RLAS). Department of Medical Imaging and Physiology, Skåne University Hospital Department of Translational medicine, Lund University, Lund, Sweden.
    Engberg, Amanda
    Högskolan i Halmstad, Akademin för ekonomi, teknik och naturvetenskap.
    Turnstedt, Max
    Högskolan i Halmstad, Akademin för ekonomi, teknik och naturvetenskap.
    Dencker, Magnus
    Department of Medical Imaging and Physiology, Skåne University Hospital Department of Translational medicine, Lund University, Lund, Sweden.
    Bremander, Ann
    FoU Spenshult, Halmstad, Sweden.
    Olsson, M. Charlotte
    Högskolan i Halmstad, Akademin för ekonomi, teknik och naturvetenskap, Rydberglaboratoriet för tillämpad naturvetenskap (RLAS).
    Cardiovascular Effects of Load Carriage in Soldiers; A Pilot Study2019Inngår i: Book of Abstracts of the 24th Annual Congress of the European College of Sport Science – 3rd - 6th July 2019, Prague – Czech Republic / [ed] Bunc, V. & Tsolakidis, E., European College of Sport Science , 2019, s. 422-423Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Introduction: Previous studies have shown that risk of physical fatigue increases if prolonged average work intensity exceeds 50% of oxygen uptake (VO2). In order to avoid persistent fatigue in a work setting, it is important to conduct suitable work capacity analyses. In physically demanding jobs where wearing protective gear and/or external load is mandatory, monitoring of cardiovascular demands through heart rate (HR) is one way to track the workers’ relative effort.  There are limited studies examining effects of load carrying on cardiovascular capacity where it appears that VO2peak differ when soldiers and firefighters are tested with work-related equipment/clothing compared to light clothing. The aim of this pilot study was to investigate effects of load (combat gear) on HR, VO2 and muscle oxygen saturation (SmO2) compared to no load in soldiers during a graded treadmill protocol.

    Methods: Eight volunteer army soldiers (1 woman, 7 men) performed a graded treadmill test until exhaustion. All soldiers performed the test twice, once with light clothes and no load (NL) and once with added load, their personal combat gear (CG), with at least 48 h between sessions. The treadmill protocol stages included supine and standing positions, followed by marching speeds of 5.4 km/h and 8 km/h at 0 incline (all 5 min) immediately followed by a set marching speed of 8 km/h with a starting incline of 2 % increasing the incline 2 % every third minute until voluntary exhaustion. Measurements of HR, VO2 and SmO2 were collected continuously and the last 30 s of each stage were averaged and used for statistical analyses (paired t-tests).

    Results: The mean added load for all soldiers with CG was 16.8 ± 1.1 kg. All soldiers completed at least 6 stages (range 6-11 stages) with both NL and CG, where time to exhaustion with NL was longer (19.1 ± 3.2 min) compared to CG (9.1 ± 2.9 min; p <0.01). Submaximal HR and VO2 were both significantly higher with CG compared to NL (at absolute intensities) at all marching speeds all soldiers completed (5.4 km/h 0 % grade - 8 km/h 4% grade; all p<0.05). For SmO2, marching with CG compared to NL resulted in increased muscle oxygen utilization, at submaximal stages 8 km/h 0% -4% grade (all p<0.05). For values at maximal effort the CG had a significantly lower VO2peak (3.7 ± 0.5 L/min) compared to NL (4.1 ± 0.6 L/min, p <0.01), whereas there was no difference in HRpeak or the lowest value of SmO2 between CG (193.1 ± 7.2 bpm; 42.4 ± 30.3%) and NL (195.4 ± 8.9 bpm; 47.0 ± 29.2%).

    Conclusions: This pilot study suggests that assessment of aerobic capacity in soldiers should be conducted with combat gear to help determine their actual work capacity during combat and other load carrying tasks. These results suggest that if soldiers’ work performance is determined without added load it overestimates their aerobic capacity (VO2peak) in tasks wearing combat gear, which might lead to added fatigability and deleterious effect on performance.

  • 14.
    Larsson, Jonas
    et al.
    Högskolan i Halmstad, Akademin för ekonomi, teknik och naturvetenskap, Rydberglaboratoriet för tillämpad naturvetenskap (RLAS). Lund University, Lund, Sweden & Swedish Armed Forces, Eksjö, Sweden.
    Olsson, M. Charlotte
    Högskolan i Halmstad, Akademin för ekonomi, teknik och naturvetenskap, Rydberglaboratoriet för tillämpad naturvetenskap (RLAS).
    Denker, Magnus
    Lund University, Lund, Sweden.
    Bremander, Ann
    Högskolan i Halmstad, Akademin för ekonomi, teknik och naturvetenskap, Rydberglaboratoriet för tillämpad naturvetenskap (RLAS). Department of Clinical Sciences, Section of Rheumatology, Lund University, Lund, Sweden.
    Self-rated physical work demands for ground combat soldiers2018Inngår i: PES 2018 3rd International Conference on Physical Employment Standards, University of Portsmouth, United Kingdom, 17-19 July 2018: Conference Book of Abstracts, 2018, s. 31-31Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Introduction: Military tasks are physically demanding, and the ability to achieve and maintain the physical capacity required to perform all military tasks are important. Previous studies in other countries have identified the most physically demanding work tasks to be carrying, lifting heavy loads, and digging. The aim of the present study was to identify the most physically demanding work tasks for Swedish ground combat soldiers and to study gender differences in perceived difficulty of the tasks.

    Methods: Based on procedural documentation, field manuals and job analyses, a questionnaire was developed that defined 30 work tasks for ground combat soldiers. To assess face and content validity, an expert focus group was used. The questionnaire was distributed to 231 ground combat soldiers, 165 of whom responded (71.4%), rating the perceived physical strain of the identified work tasks.

    Results: Of the 30 item work tasks included in the survey, five were selected as the most physically demanding. Transport of wounded was rated as the most demanding task both for aerobic endurance and strength. Other highly demanding tasks for aerobic capacity were low/high crawl, dismounted attack in close country, urban and rough terrain, and carrying heavy loads. For muscle strength demands there were a total of 11 different work task ranked for hand-, arm-, leg-, and core strength although many of them only occurred in one of the areas of interest. Carrying heavy loads were ranked in second place except for leg and core strength there it was in third place, instead high and low crawl was ranked very strenuous for leg and core strength. Care of wounded were ranked high for hand strength but not so hard for the rest of the areas.

    Conclusions: Swedish ground combat soldiers rate many tasks as physically demanding. Almost all the identified tasks were physically challenging and contains elements of lifting and carrying, which demand personnel’s muscular strength and muscular endurance capabilities for the soldiers. There were no significant differences in ranked physical requirements between male and female soldiers although they sometimes ranked the tasks in different order. 

  • 15.
    Malmborg, Julia
    et al.
    Högskolan i Halmstad, Akademin för ekonomi, teknik och naturvetenskap, Rydberglaboratoriet för tillämpad naturvetenskap (RLAS).
    Bremander, Ann
    Högskolan i Halmstad, Akademin för ekonomi, teknik och naturvetenskap, Rydberglaboratoriet för tillämpad naturvetenskap (RLAS). Lund University, Lund, Sweden & Spenshult Research and Development Center, Halmstad, Sweden.
    Bergman, Stefan
    Högskolan i Halmstad, Akademin för hälsa och välfärd, Centrum för forskning om välfärd, hälsa och idrott (CVHI). Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden; Lund University, Lund, Sweden & Spenshult Research and Development Center, Halmstad, Sweden.
    Olsson, Charlotte M.
    Högskolan i Halmstad, Akademin för ekonomi, teknik och naturvetenskap, Rydberglaboratoriet för tillämpad naturvetenskap (RLAS).
    Pain and its association to health, orthorexia nervosa, sports performance, and physical maturity in sport school adolescents2017Inngår i: Proceedings of the Nordic Sport Science Conference – ‘The Double-Edged Sword of Sport: Health Promotion Versus Unhealthy Environments’ / [ed] Hertting, K. & Johnson, U., Halmstad: Halmstad University Press, 2017, s. 56-57Konferansepaper (Fagfellevurdert)
  • 16.
    Malmborg, Julia
    et al.
    Högskolan i Halmstad, Akademin för ekonomi, teknik och naturvetenskap, Rydberglaboratoriet för tillämpad naturvetenskap (RLAS).
    Bremander, Ann
    Högskolan i Halmstad, Akademin för ekonomi, teknik och naturvetenskap, Rydberglaboratoriet för tillämpad naturvetenskap (RLAS). Spenshult Research and Development Center, Halmstad, Sweden & Lund University, Lund, Sweden.
    Olsson, Charlotte M.
    Högskolan i Halmstad, Akademin för ekonomi, teknik och naturvetenskap, Rydberglaboratoriet för tillämpad naturvetenskap (RLAS).
    Bergman, Stefan
    Högskolan i Halmstad, Akademin för hälsa och välfärd, Centrum för forskning om välfärd, hälsa och idrott (CVHI). University of Gothenburg, Gothenburg, Sweden; Spenshult Research and Development Center, Halmstad, Sweden & Lund University, Lund, Sweden.
    Health status, physical activity, and orthorexia nervosa: A comparison between exercise science students and business students2017Inngår i: Appetite, ISSN 0195-6663, E-ISSN 1095-8304, Vol. 109, s. 137-143Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Orthorexia nervosa is described as an exaggerated fixation on healthy food. It is unclear whether students in health-oriented academic programs, highly focused on physical exercise, are more prone to develop orthorexia nervosa than students in other educational areas. The aim was to compare health status, physical activity, and frequency of orthorexia nervosa between university students enrolled in an exercise science program (n = 118) or a business program (n = 89). The students completed the Short Form-36 Health Survey (SF-36), the International Physical Activity Questionnaire (IPAQ), and ORTO-15, which defines orthorexia nervosa as a sensitive and obsessive behavior towards healthy nutrition. The SF-36 showed that exercise science students scored worse than business students regarding bodily pain (72.8 vs. 82.5; p = 0.001), but better regarding general health (83.1 vs. 77.1; p = 0.006). Of 188 students, 144 (76.6%) had an ORTO-15 score indicating orthorexia nervosa, with a higher proportion in exercise science students than in business students (84.5% vs. 65.4%; p = 0.002). Orthorexia nervosa in combination with a high level of physical activity was most often seen in men in exercise science studies and less often in women in business studies (45.1% vs. 8.3%; p < 0.000). A high degree of self-reporting of pain and orthorexia nervosa in exercise science students may cause problems in the future, since they are expected to coach others in healthy living. Our findings may be valuable in the development of health-oriented academic programs and within student healthcare services. © 2016 Elsevier Ltd

  • 17.
    Malmborg, Julia
    et al.
    Högskolan i Halmstad, Akademin för ekonomi, teknik och naturvetenskap, Rydberglaboratoriet för tillämpad naturvetenskap (RLAS).
    Bremander, Ann
    Högskolan i Halmstad, Akademin för ekonomi, teknik och naturvetenskap, Rydberglaboratoriet för tillämpad naturvetenskap (RLAS).
    Olsson, M. Charlotte
    Högskolan i Halmstad, Akademin för ekonomi, teknik och naturvetenskap, Rydberglaboratoriet för tillämpad naturvetenskap (RLAS).
    Bergman, A.-C.
    Spenshult Research and Development Center, Halmstad, Sweden.
    Brorsson, Sofia
    Spenshult Research and Development Center, Halmstad, Sweden.
    Bergman, Stefan
    Primary Health Care Unit, Department of Public Health and Community Medicine, Institute of Medicine, The Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden.
    Sleeping Problems and Anxiety is Associated to Chronic Multisite Musculoskeletal Pain in Swedish High School Students2018Inngår i: Annals of the Rheumatic Diseases, ISSN 0003-4967, E-ISSN 1468-2060, Vol. 77, nr Suppl. 2, s. 226-226, artikkel-id OP0361-HPRArtikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Background: The relationship between chronic multisite musculoskeletal pain (CMP) and sleep is complex, where pain can lead to sleeping problems and lack of sleep can intensify the pain perception. Most previous studies relates to adults, but adolescents may also suffer from CMP, and there is a need for more knowledge regarding the relationships between CMP and sleeping problems, stress, anxiety, depression, and health status.

    Objectives: To study background factors associated to CMP in first year Swedish high school students.

    Methods: First year Swedish high school students (n=296) were invited to complete questionnaires on chronic pain (mannequin with 18 body regions), sleeping problems (Uppsala Sleep Inventory, four items scored from 1–5), stress (ELO questions, scored from 1–5), anxiety and depression (Hospital Anxiety and Depression Scale, scored from 0–21), health status (EQ-5D, scored from 0 to 1, worst to best) and physical activity (International Physical Activity Questionnaire, categorised into low, moderate and high levels). Stress and sleeping items were dichotomized into 1–3 points (best) vs 4–5 points (worst). Individuals scoring at least severe problems (4 points) at one or more sleeping items were classified as having severe sleeping problems. HADS were categorised as non-cases (0–7), possible7–10 and probable cases (11–21 points). Students were grouped as having CMP (pain present in ≥3 regions) or not (no chronic pain or chronic pain in 1–2 regions). Multiple logistic regression analyses (adjusted for sex) with CMP as dependent variable were performed in SPSS, version 24.

    Results: 254 students (86% of total sample, 87 boys and 167 girls) with a mean age of 16.1 (SD 0.6) years participated in the study. CMP was present in 25 (9.8%) students with no differences between boys and girls (8.0% vs 10.8%; p=0.488). Having CMP was associated with reporting severe sleeping problems (OR 2.49, 95% CI: 1.06 to 5.81, p=0.035) with initiating sleep, maintaining sleep, early morning awakenings and/or not feeling restored after sleep in comparison to the other students. Students with CMP were more likely to be categorised as probable cases for anxiety (OR 3.06, 95% CI: 1.09 to 8.61, p=0.034), but there were no associations for possible cases for anxiety (OR 1.15, 95% CI: 0.38 to 3.51, p=0.800), possible cases (OR 2.03, 95% CI: 0.63 to 6.54), or probable cases for depression (OR 3.35, 95% CI: 0.33 to 33.83). There was a nearly significant association between stress and belonging to the CMP group (OR 2.31, 95% CI: 0.97 to 5.53, p=0.059). A higher self-reported health status was associated to a lower likelihood for CMP (OR 0.04, 95% CI: 0.01 to 0.27, p=0.001). Distribution of physical activity levels of low, moderate and high was not significantly associated to having CMP in comparison with not having it.

    Conclusions: One in ten high school students fulfilled criteria for having chronic multisite musculoskeletal pain. CMP was associated to sleeping problems, anxiety, and a worse health status. The results from this study may be used by school health-care professionals in their preventive work to promote student’s health.

    Disclosure of Interest: None declared

  • 18.
    Malmborg, Julia
    et al.
    Högskolan i Halmstad, Akademin för ekonomi, teknik och naturvetenskap, Rydberglaboratoriet för tillämpad naturvetenskap (RLAS).
    Olsson, Charlotte M.
    Högskolan i Halmstad, Akademin för ekonomi, teknik och naturvetenskap, Rydberglaboratoriet för tillämpad naturvetenskap (RLAS).
    Bergman, Stefan
    Sahlgrenska Academy, Gothenburg University, Gothenburg, Sweden.
    Bremander, Ann
    Högskolan i Halmstad, Akademin för ekonomi, teknik och naturvetenskap, Rydberglaboratoriet för tillämpad naturvetenskap (RLAS).
    Daily Musculoskeletal Pain Affects Health And Sports Performance Negatively In Youth Athletes2017Inngår i: Medicine & Science in Sports & Exercise, ISSN 0195-9131, E-ISSN 1530-0315, Vol. 49, s. 972-972Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In sports, musculoskeletal pain (MSP) is often studied from the perspective of sport specific injuries, why little is known about the prevalence of daily or multisite MSP that does not affect participation in sports. It is also unclear if daily or multisite MSP is a risk factor for worse health-related quality of life (HRQoL) and worse sports performance in youth athletes.

    PURPOSE: To study how HRQoL and sports performance is affected by daily MSP in youth athletes that are able to participate in sports.

    METHODS: 136 Swedish youth athletes attending a sport school (13 to 14 years, boys n=83, girls n=53) completed the EQ-5D measuring HRQoL (range 0 to 1, worst to best), a pain questionnaire including current pain (yes/no), pain in 18 body regions (never to rarely/monthly to weekly/more than once a week to almost daily), and pain intensity in the last week (0 to 10, best to worst), anthropometric measures to estimate biological age, and sports performance tests (grip strength, 20 meter sprint, and countermovement jump(CMJ)).

    RESULTS: 109 to 117 of the 136 students answered the different pain questions. 53 of 113 (47%) reported current MSP, and 28 of 109 (26%) experienced MSP ‘more than once a week to almost daily’ from one or more body regions (frequent MSP group), while 28% (n=30) stated ‘never to rarely’ in MSP (no MSP group). Boys in the frequent MSP group reported worse HRQoL, higher pain intensity, performed worse in all sports performance tests, and had a younger biological age than boys in the no MSP group. Girls in the frequent MSP group reported worse HRQoL and higher pain intensity than the girls in the no MSP group. No other differences were found (table).

    CONCLUSIONS: Every other youth athlete attending a sport school reported current MSP and one out of four reported almost daily MSP. MSP affects HRQoL negatively in both boys and girls, and sports performance negatively in boys. The prevalence of MSP in youth athletes is concerning since pain in younger ages may predict pain in adult ages.

    © 2017 American College of Sports Medicine

  • 19.
    Malmborg, Julia
    et al.
    Högskolan i Halmstad, Akademin för ekonomi, teknik och naturvetenskap, Rydberglaboratoriet för tillämpad naturvetenskap (RLAS). Spenshult Research and Development Center, Halmstad, Sweden.
    Olsson, M Charlotte
    Högskolan i Halmstad, Akademin för ekonomi, teknik och naturvetenskap, Rydberglaboratoriet för tillämpad naturvetenskap (RLAS). Malmö Sports Academy, Malmö, Sweden.
    Bergman, Stefan
    The Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden & Lund University, Lund, Sweden.
    Bremander, Ann
    Högskolan i Halmstad, Akademin för ekonomi, teknik och naturvetenskap, Rydberglaboratoriet för tillämpad naturvetenskap (RLAS). Lund University, Lund, Sweden.
    Musculoskeletal pain and its association with maturity and sports performance in 14-year-old sport school students2018Inngår i: BMJ Open Sport & Exercise Medicine, ISSN 2055-7647, Vol. 4, nr 1, artikkel-id e000395Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Objectives: In youth sports, musculoskeletal pain is often studied from the standpoint of sports injuries, but little is known about pain conditions in which athletes still participate. The aim was to study the frequency of pain and associations with maturity offset, health status and sports performance in 14-year-old sport school students.

    Methods: Cross-sectional design. One hundred and seventy-eight students (108 boys and 70 girls) completed anthropometric measures for maturity offset (height, weight and sitting height), questionnaires (pain mannequin and EQ-5D for health status) and sports performance tests (sprint, agility, counter-movement jump and grip strength). Differences between groups were analysed with Student’s t-test and analysis of covariance.

    Results: Thirty-one students (18.6%) reported infrequent pain, 85 (50.9%) frequent pain and 51 (30.5%) constant pain. Students in the constant pain group had worse health status than those in the infrequent pain group. Boys with constant pain (n=27) had a lower mean maturity offset (–0.38 vs 0.07 years; p=0.03) than boys with infrequent pain (n=22), and pain was associated with worse sports performance. There was no difference in maturity or sports performance between girls with constant pain (n=24) and girls with infrequent pain (n=9).

    Conclusion: Musculoskeletal pain is common in sport school students and coincides with worse health status and with a younger biological age in boys. The high prevalence of pain should be acknowledged by coaches and student healthcare workers in order to promote a healthy and sustainable development in young athletes. © Author(s) (or their employer(s)) 2018.

  • 20.
    Malmborg, Julia S
    et al.
    Högskolan i Halmstad, Akademin för ekonomi, teknik och naturvetenskap, Rydberglaboratoriet för tillämpad naturvetenskap (RLAS). Spenshult Research and Development Center, Halmstad, Sweden.
    Bremander, Ann
    University of Southern Denmark, Odense, Denmark & University Hospital of Southern Denmark, Sønderborg, Denmark & Lund University, Lund, Sweden.
    Olsson, M. Charlotte
    Högskolan i Halmstad, Akademin för ekonomi, teknik och naturvetenskap, Rydberglaboratoriet för tillämpad naturvetenskap (RLAS).
    Bergman, Anna-Carin
    Spenshult Research and Development Center, Halmstad, Sweden.
    Brorsson, A Sofia
    Spenshult Research and Development Center, Halmstad, Sweden.
    Bergman, Stefan
    Lund University, Lund, Sweden & The Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden..
    Worse health status, sleeping problems, and anxiety in 16-year-old students are associated with chronic musculoskeletal pain at three-year follow-up2019Inngår i: BMC Public Health, ISSN 1471-2458, E-ISSN 1471-2458, Vol. 19, nr 1, artikkel-id 1565Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    BACKGROUND: Chronic musculoskeletal pain is common in adolescents, and it has been shown that adolescents with pain may become young adults with pain. Pain often coincides with psychosomatic symptoms in adults, but little is known about longitudinal associations and predictors of pain in adolescents. The aim was to investigate chronic musculoskeletal pain and its associations with health status, sleeping problems, stress, anxiety, depression, and physical activity in 16-year-old students at baseline, and to identify risk factors using a three-year follow-up.

    METHODS: This was a longitudinal study of 256 students attending a Swedish upper secondary school. Questionnaires regarding chronic musculoskeletal pain and distribution of pain (mannequin), health status (EQ-5D-3 L), sleeping problems (Uppsala Sleep Inventory), stress symptoms (single-item question), anxiety and depression (Hospital Anxiety and Depression Scale), and physical activity (International Physical Activity Questionnaire) were issued at baseline and follow-up. Student's t-test and chi2 test were used for descriptive statistics and logistic regression analyses were used to study associations between chronic pain and independent variables.

    RESULTS: Fifty-two out of 221 students at baseline (23.5%) and 39 out of 154 students at follow-up (25.3%) were categorized as having chronic musculoskeletal pain. Chronic musculoskeletal pain at follow-up was separately associated with reporting of an EQ-5D value below median (OR 4.06, 95% CI 1.83-9.01), severe sleeping problems (OR 3.63, 95% CI 1.69-7.82), and possible anxiety (OR 4.19, 95% CI 1.74-10.11) or probable anxiety (OR 3.82, 95% CI 1.17-12.48) at baseline. Similar results were found for associations between chronic musculoskeletal pain and independent variables at baseline. In multiple logistic regression analysis, chronic musculoskeletal pain at baseline was a predictor of chronic musculoskeletal pain at follow-up (OR 2.99, 95% CI 1.09-8.24, R2 = 0.240).

    CONCLUSION: Chronic musculoskeletal pain at baseline was the most important predictor for reporting chronic musculoskeletal pain at the three-year follow-up, but a worse health status, severe sleeping problems, and anxiety also predicted persistence or development of chronic musculoskeletal pain over time. Interventions should be introduced early on by the school health services to promote student health.

  • 21.
    Marx, James O
    et al.
    Department of Biology, University of Pennsylvania, Philadelphia, PA 19104, United States.
    Olsson, M Charlotte
    Department of Clinical Neurophysiology, Uppsala University Hospital, 751 85 Uppsala, Sweden.
    Larsson, Lars
    Department of Clinical Neurophysiology, Uppsala University Hospital, 751 85, Uppsala, Sweden.
    Scaling of skeletal muscle shortening velocity in mammals representing a 100,000-fold difference in body size2006Inngår i: Pflügers Archiv: European Journal of Physiology, ISSN 0031-6768, E-ISSN 1432-2013, Vol. 452, nr 2, s. 222-230Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    To fully understand the effect of scaling on skeletal muscle shortening velocity (V 0), it is important to know which phenotypic characteristics drive the changes between species. The purpose of the current investigation was to compare the effects of body mass and femur length, as an estimate of total limb length, on V 0 in species that cover a 100,000-fold range of body masses. Using the slack test procedure, V 0 was determined for fibers expressing types I and IIa myosin heavy chain (MyHC) isoforms in the mouse, rat, dog, human, horse, and rhinoceros under identical experimental conditions. A significant scaling effect on V 0 was detected when compared to body mass (type I fibers, r=0.95, p<0.01; type IIa fibers, r=0.83, p<0.05). However, the horse's V 0 for both fiber types was faster than the human's, despite having a 5-fold greater body mass than the human. When V 0 was scaled vs limb length, the strength of the relationships improved in fibers expressing both types I and IIa MyHC (r=0.98, p<0.001, and r=0.89, p<0.05, respectively) and scaled with the expected relationship, with the species with the shorter femur, the horse, having the faster V 0. A similar effect can be seen with stride frequency scaling more closely with limb length than body mass. These results suggest that limb length, not body mass, is a more relevant factor driving the scaling effect on skeletal muscle shortening velocity.

  • 22.
    Olsson, Charlotte M.
    et al.
    Högskolan i Halmstad, Akademin för ekonomi, teknik och naturvetenskap, Rydberglaboratoriet för tillämpad naturvetenskap (RLAS).
    Bernhardsson, Lina
    Högskolan i Halmstad, Akademin för ekonomi, teknik och naturvetenskap.
    Bremander, Ann
    Högskolan i Halmstad, Akademin för ekonomi, teknik och naturvetenskap, Rydberglaboratoriet för tillämpad naturvetenskap (RLAS).
    Electromyographic Analysis of Left and Right Side Gluteus Medius in Unilateral and Bilateral Bodyweight Exercises2017Inngår i: Medicine & Science in Sports & Exercise, ISSN 0195-9131, E-ISSN 1530-0315, Vol. 49, nr 5S, s. 464-465Artikkel i tidsskrift (Fagfellevurdert)
  • 23.
    Olsson, Charlotte M.
    et al.
    Högskolan i Halmstad, Akademin för ekonomi, teknik och naturvetenskap, Rydberglaboratoriet för tillämpad naturvetenskap (RLAS).
    Fälth, Jenny
    Högskolan i Halmstad, Akademin för ekonomi, teknik och naturvetenskap.
    Ahlebrand, August
    Högskolan i Halmstad, Akademin för ekonomi, teknik och naturvetenskap.
    Bremander, Ann
    Högskolan i Halmstad, Akademin för ekonomi, teknik och naturvetenskap, Rydberglaboratoriet för tillämpad naturvetenskap (RLAS).
    Sex-Differences In Bench Press Muscle Activation With Pre-Exhaustion Of Triceps Brachii2018Inngår i: Conference Abstracts, 2018, s. 67-68Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Purpose: Pre-exhaustion is a resistance training method which activates a stronger single-joint muscle to momentary exhaustion directly before a multi-joint exercise including the pre-exhausted muscle. This results in greater recruitment of muscles in the multi-joint exercise to further increase muscle strength. The pre-exhaustion method in bench press has mainly been studied in men and it is uncertain if sex-differences exists. Men are stronger than women in absolute strength, especially in the upper body but if this holds true for upper body relative strength is debated. The purpose was to investigate muscle activity by surface electromyography (EMG) between women and men in bench press with and without pre-exhaustion of triceps brachii (TB) and to compare relative strength in 10RM bench press between the sexes.

    Methods: 15 women and 15 men in their 20s with weight lifting experience were recruited to the study. During the first session body composition and 10 repetition maximum (10RM) bench press were determined Participants performed both protocol A and B in a cross-over design on separate days. Protocol A began with 10 RM bench press, five minutes recovery, pre-exhaustion exercise (triceps extensions to failure) immediately followed by a second round of bench press with the same 10RM load as before pre-exhaustion. Protocol B started with triceps extensions to failure immediately before bench press at their before established 10RM, five minutes of recovery then they performed 10RM bench press again. IN both protocols, EMG electrodes were attached to TB), pectoralis major (PM) and deltoideus anterior (DA). EMG values were normalized to maximum voluntary isometric contraction (MVIC) and expressed as % MVIC.

    Results: Bench press only EMG activity in %MVIC was similar between women and men, but analysis of variance (TB interaction p=0.02) showed that women had higher %MVIC in TB after pre-exhaustion whereas muscle activity decreased in men compared to bench press without pre-exhaustion. Yet, the number of repetitions completed in bench press after pre-exhaustion of TB were the same (women 4.3 ± 2.6 vs men 3.8 ± 2.2; p=0.55). As expected, in 10RM weight men (64.0 ± 7.1 kg) were stronger than women (37.1 ± 6.5 kg; p<0.01), however when related to fat free mass no difference was evident in relative strength between women and men.

    Conclusion: Men and women have similar muscle activation patterns during a 10RM bench press, but TB pre-exhaustion followed by a bench press appears to have a greater effect on TB activation in women compared to men. Absolute strength was greater in men, but normalized to fat free mass women and men had similar upper body relative strength.

  • 24.
    Olsson, M Charlotte
    et al.
    Högskolan i Halmstad, Akademin för ekonomi, teknik och naturvetenskap, Bio- och miljösystemforskning (BLESS), Biomekanik och biomedicin.
    Frandsen, Björn
    Högskolan i Halmstad, Akademin för ekonomi, teknik och naturvetenskap, Bio- och miljösystemforskning (BLESS).
    Electromyography Muscle Activity in Unilateral and Bilateral Squats with Relative Loads2015Konferansepaper (Annet vitenskapelig)
    Abstract [en]

    Introduction

    Unilateral strength training is becoming popular as a complement to bilateral training particularly in athletes active in sports performed primarily on one leg. Some studies have shown improved performance after unilateral compared to bilateral strength training, however the underlying cause for this improvement is unclear. The aim of this study was to compare electromyography (EMG) muscle activity in unilateral and bilateral squats performed with 80% of 1repetition maximum (RM) performed in a smith machine.

    Methods

    Participants in the study were 12 healthy women and men (mean age 25±2 years) with previous weight-lifting experience. EMG activity was measured during the concentric phase in the muscles vastus lateralis, biceps femoris, gluteus medius and erector spinae during A) a maximal voluntary isometric contraction (MVIC), B) 1RM squat (90 degree knee flexion) bilaterally and unilaterally, and C) 3 repetitions 80% of 1RM for both the unilateral and bilateral stance, where each squat was performed at a set speed with the aid of a metronome.

    Results

    EMG activities, calculated as percent of MVIC, in thigh and hip muscles (vastus lateralis, biceps femoris, gluteus medius) were significantly higher (p<0.01 for all) in the unilateral compared to the bilateral stance. The highest increase in EMG activity was in the gluteus medius where the unilateral squat elicited a 2.9 increase compared to bilateral stance. Unilateral stance muscle activation was in vastus lateralis 1.2 times higher and in biceps femoris 1.5 times higher compared to the bilateral stance. For the trunk muscle erector spinae, the opposite was apparent. EMG activity was 0.6 times lower (p<0.01) when the squat was performed unilaterally compared to bilaterally.

    Discussion

    Even when the load is made relative to the 1RM for each stance the muscles in especially the gluteus medius but also vastus lateralis and biceps femoris is activated to a higher degree when performed unilaterally which could be a partial explanation as to why the unilateral stance can be beneficial to include in a strength training regime despite the absolute load being lower.

  • 25.
    Olsson, M Charlotte
    et al.
    Högskolan i Halmstad, Akademin för ekonomi, teknik och naturvetenskap, Bio- och miljösystemforskning (BLESS).
    Frandsen, Björn
    Högskolan i Halmstad, Akademin för ekonomi, teknik och naturvetenskap, Bio- och miljösystemforskning (BLESS).
    Lower body electromyography muscle activity differences between unilateral and bilateral squats with relative loads2014Inngår i: Medicine & Science in Sports & Exercise, ISSN 0195-9131, E-ISSN 1530-0315, Vol. 46, nr 5S, s. 962-963Artikkel i tidsskrift (Fagfellevurdert)
  • 26.
    Olsson, M. Charlotte
    et al.
    Högskolan i Halmstad, Akademin för ekonomi, teknik och naturvetenskap, Rydberglaboratoriet för tillämpad naturvetenskap (RLAS).
    Fälth, Jenny
    Högskolan i Halmstad, Akademin för ekonomi, teknik och naturvetenskap.
    Ahlebrand, August
    Högskolan i Halmstad, Akademin för ekonomi, teknik och naturvetenskap.
    Andersson, Åsa
    Högskolan i Halmstad, Akademin för ekonomi, teknik och naturvetenskap, Rydberglaboratoriet för tillämpad naturvetenskap (RLAS).
    Haglund, Emma
    Högskolan i Halmstad, Akademin för ekonomi, teknik och naturvetenskap, Rydberglaboratoriet för tillämpad naturvetenskap (RLAS).
    Bench press muscle activation with triceps brachii pre-exhaustion in females and males2019Inngår i: Journal of Sports Sciences, ISSN 0264-0414, E-ISSN 1466-447X, Vol. 37, nr Supp1, s. 71-72Artikkel i tidsskrift (Fagfellevurdert)
  • 27.
    Olsson, M Charlotte
    et al.
    Uppsala University, Department of Neuroscience, Clinical Neurophysiology, Ing 85 3 tr., 751 85 Uppsala, Sweden.
    Krüger, Martina
    University of Münster, Physiology and Biophysics Unit, Schlossplatz 5, D-48149 Münster, Germany .
    Meyer, Lars-Henrik
    University of Münster, Physiology and Biophysics Unit, Schlossplatz 5, D-48149 Münster, Germany .
    Ahnlund, Lena
    Rehabilitation Medicine, 75185 Uppsala, Sweden.
    Gransberg, Lennart
    Uppsala University, Department of Neuroscience, Clinical Neurophysiology, Ing 85 3 tr., 751 85 Uppsala, Sweden.
    Linke, Wolfgang A
    University of Münster, Physiology and Biophysics Unit, Schlossplatz 5, D-48149 Münster, Germany.
    Larsson, Lars
    Uppsala University, Department of Neuroscience, Clinical Neurophysiology, Ing 85 3 tr., 751 85 Uppsala, Sweden.
    Fibre type-specific increase in passive muscle tension in spinal cord-injured subjects with spasticity2006Inngår i: Journal of Physiology, ISSN 0022-3751, E-ISSN 1469-7793, Vol. 577, nr 1, s. 339-352Artikkel i tidsskrift (Fagfellevurdert)
  • 28.
    Olsson, M Charlotte
    et al.
    Department of Integrative Physiology, University of Colorado, Boulder, CO, United States.
    Palmer, B M
    Department of Integrative Physiology, University of Colorado, Boulder, CO, United States.
    Stauffer, B L
    Dept. Molec., Cell.,/Devmtl. Biol., University of Colorado, Boulder, CO, United States.
    Leinwand, L A
    Dept. Molec., Cell.,/Devmtl. Biol., University of Colorado, Boulder, CO, United States.
    Moore, R L
    Department of Integrative Physiology, University of Colorado, Boulder, CO, United States.
    Morphological and functional alterations in ventricular myocytes from male transgenic mice with hypertrophic cardiomyopathy2004Inngår i: Circulation Research, ISSN 0009-7330, E-ISSN 1524-4571, Vol. 94, nr 2, s. 201-207Artikkel i tidsskrift (Fagfellevurdert)
  • 29.
    Olsson, M Charlotte
    et al.
    Department of Physiology, Univ. Wisconsin Cardiovasc. Res. C., Univ. of Wisconsin Medical School, Madison, WI 53706, United States.
    Patel, J R
    Department of Physiology, Univ. Wisconsin Cardiovasc. Res. C., Univ. of Wisconsin Medical School, Madison, WI 53706, United States.
    Fitzsimons, D P
    Department of Physiology, Univ. Wisconsin Cardiovasc. Res. C., Univ. of Wisconsin Medical School, Madison, WI 53706, United States.
    Walker, J W
    Department of Physiology, Univ. Wisconsin Cardiovasc. Res. C., Univ. of Wisconsin Medical School, Madison, WI 53706, United States.
    Moss, R L
    Department of Physiology, Univ. Wisconsin Cardiovasc. Res. C., Univ. of Wisconsin Medical School, Madison, WI 53706, United States.
    Basal myosin light chain phosphorylation is a determinant of Ca2+ sensitivity of force and activation dependence of the kinetics of myocardial force development2004Inngår i: American Journal of Physiology. Heart and Circulatory Physiology, ISSN 0363-6135, E-ISSN 1522-1539, Vol. 287, nr 6, s. H2712-H2718Artikkel i tidsskrift (Fagfellevurdert)
  • 30.
    Parker, James
    et al.
    Högskolan i Halmstad, Akademin för ekonomi, teknik och naturvetenskap, Rydberglaboratoriet för tillämpad naturvetenskap (RLAS). Scandinavian College of Sport, Gothenburg, Sweden.
    Hellström, John
    Högskolan i Halmstad, Akademin för ekonomi, teknik och naturvetenskap. Swedish Golf Federation, Stockholm, Sweden.
    Ivarsson, Andreas
    Högskolan i Halmstad, Akademin för hälsa och välfärd, Centrum för forskning om välfärd, hälsa och idrott (CVHI).
    Johnson, Urban
    Högskolan i Halmstad, Akademin för hälsa och välfärd, Centrum för forskning om välfärd, hälsa och idrott (CVHI).
    Olsson, Charlotte
    Högskolan i Halmstad, Akademin för ekonomi, teknik och naturvetenskap, Rydberglaboratoriet för tillämpad naturvetenskap (RLAS).
    The Variability in Kinematics and Carry in a Longitudinal Intra-individual Study of Elite Golfers2016Inngår i: Abstracts: July 18-22, 2016, 2016, s. 47-48Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Purpose: To hit further and with high accuracy is important for success in the long game in golf. Even for very accomplished golfers a certain degree of between shot variance is evident even when trying to consistently repeat a successful shot. The consistency is determined by the biomechanics of the golfer, which influences club head speed (CHS) and position, and initial ball launch conditions, which in combination with environmental factors determine shot outcome. Previous research has identified several biomechanical variables associated with variance in CHS, including thorax rotation speed  and lead arm speed (LAS). Pilot data from our laboratory have indicated moderate non-significant relationship between CHS and carry in elite male golfers when studied over time. Thus, the aim of this study was to explore the relationship between peak speed of the pelvis, thorax, and lead upper arm and carry over time, investigating both within and between session variability in elite male golfers.

    Methods: Six elite male golfers (handicap range -3 to +0.5) (age range 21-23 years) were included in this study. The golfers were studied on four separate occasions over a year.  Each test occasion included a golf specific warm-up of the golfers’ choice, then subjects were instructed to hit five balls with their driver and use the swing that was as ‘normal ‘as possible. Data on swing kinematics was collected using a four sensor electromagnetic motion capture system at 120Hz (Polhemus Inc. USA). Nine landmarks were digitized to define segment lengths, orientations and joint axes. CHS and carry were collected using a launch monitor (Trackman3e, v.3.2, Trackman, Denmark). The swing events were determined from sensors on the club; top of backswing was determined when the club changes direction from backswing to downswing. Impact was determined when the clubhead reaches the horizontal position equivalent to where it was at address. Angular velocities and displacements of the pelvis, thorax, and lead arm were calculated using standard biomechanics principles in conjunction with advanced motion measurement software (AMM 3D, USA). No data smoothing techniques were used before data analysis. IBM SPSS v.22 was used to analyse the data through hierarchical multilevel modelling (MLM). First a baseline model without predictors was run, then MLM was repeated with predictors where the first level of the data contained carry and kinematic data from each shot (within session level). At the second level, the carry scores were nested within sessions and analysed between sessions. Lastly, at the third level, the sessions were nested within players (between players). Carry was used as outcome variable and kinematics as predictor variables with a probability level of 0.05.

    Results: Initially MLM baseline model for carry only, was tested) without predictors. The results showed a statistical significant intercept (Estimate = 226.24, p<.001). Intraclass correlations (ICC) suggested that 32.5% of the variance in carry were present within sessions (level 1), whilst 38.0% were attributed to differences in carry between sessions (level 2). Results from the second MLM generated an improved model fit (-2 LL & BIC) where peak speeds of the pelvis, thorax, and lead upper arm were included as fixed effect covariates on level 1. The result showed that peak LAS was a statistically significant predictor of carry (β=.17, p=.001) whereas peek speed of neither thorax (β=-.04, p=.364) nor pelvis (β=.02, p=.673) had any statistically significant relationship with carry.

    Discussion: The present study found that 32.5% of variation in shot consistency can be explained at the within session level (influenced by for example variance in centeredness of impact), and 38% of variation in shot consistency can be explained at the between session level (influenced by for example environmental factors). Furthermore, LAS was the only significant predictor of within session variance in carry. Our results indicated peak LAS speed as a predictor of within session variance in carry and this is partly supported by previous research who found golfers with higher arm speed had higher ball velocity than golfers with lower arm speed(Healy et al., 2011). However, results from our pilot study differ from previous research which reports a relationship between peak thorax speed and driver performance. The difference could be due to our results being based on longitudinal data at intra-individual level, whereas previous studies have used a cross-sectional study design, different analysis methods and reported at an inter-individual level. In conclusion, our preliminary data show that within session LAS is a predictor of carry distance when the objective is shot consistency. Practitioners may consider training strategies to optimize arm speed when improve driving consistency among elite golfers. 

    References

    Healy, A., Moran, K. A., Dickson, J., Hurley, C., Smeaton, A. F., O'Connor, N. E., . . . Chockalingam, N. (2011). Analysis of the 5 iron golf swing when hitting for maximum distance. Journal of sports sciences, 29(10), 1079-1088. 

  • 31.
    Parker, James
    et al.
    Högskolan i Halmstad, Akademin för hälsa och välfärd, Centrum för forskning om välfärd, hälsa och idrott (CVHI). Scandinavian College of Sport, Gothenburg, Sweden.
    Hellström, John
    Swedish Golf Federation, Stockholm, Sweden.
    Olsson, M. Charlotte
    Högskolan i Halmstad, Akademin för ekonomi, teknik och naturvetenskap, Rydberglaboratoriet för tillämpad naturvetenskap (RLAS).
    Differences in kinematics and driver performance in elite female and male golfers2019Inngår i: Sports Biomechanics, ISSN 1476-3141, E-ISSN 1752-6116Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The aim of this study was to compare swing kinematic differences between women and men and investigate which variables predict clubhead speed (CHS) and carry distance (CD) whilst accounting for individual variation. Methods: Swing kinematics and driver performance data were collected on 20 (10 women) elite golfers (HCP 0.7 ± 1.4). We used Bayesian T-test for between sex comparison of swing kinematics and Bayesian Analysis of covariance (ANCOVA) to produce general linear models for CHS and carry distance for elite female and male golfers separately. Results: There was strong evidence that the driver performance variables CHS and CD were decreased in women compared to men, and two kinematic variables; time to arm peak speed downswing and angular wrist peak speed were slower in women. The ANCOVAs identified very strong to overwhelming evidence that participant as a fixed factor was a determinant of CHS for both women and men but was not a determinant of CD. Conclusion: when looking to enhance driver performance among high-level golfers, coaches should be aware that variables that determine CHS and CD differ among women and men and if the aim is to improve CHS coaches should not forget the importance of individual swing characteristics. © 2019 Parker, Hellström & Olsson. Published by Informa UK Limited, trading as Taylor & Francis Group.

  • 32.
    Parker, James
    et al.
    Högskolan i Halmstad, Akademin för ekonomi, teknik och naturvetenskap, Rydberglaboratoriet för tillämpad naturvetenskap (RLAS).
    Hellström, John
    Högskolan i Halmstad, Akademin för ekonomi, teknik och naturvetenskap, Rydberglaboratoriet för tillämpad naturvetenskap (RLAS). Swedish Golf Federation, Stockholm, Sweden.
    Olsson, M. Charlotte
    Högskolan i Halmstad, Akademin för ekonomi, teknik och naturvetenskap, Rydberglaboratoriet för tillämpad naturvetenskap (RLAS).
    Relationships between golf swing kinematics and driver performance in elite golfersManuskript (preprint) (Annet vitenskapelig)
    Abstract [en]

    Swing kinematics and driver performance are considered important factors in golf performance. In golf research clubhead speed (CHS) is commonly used as the driver performance measure, whereas carry distance (CD) is less investigated and together with final ball position determine the success of a drive. The aim of this study was to investigate which kinematic factors of the pelvis, thorax, and lead arm explain CHS and/or CD. Swing kinematics data on 15 elite golfers were collected using an electromagnetic 3-D system and a doppler-radar launch monitor system. Variables that emerged as important for both CHS and CD were: reduced pelvis rotation top of backswing (TOB); reduced X-factor TOB; and more thorax lateral bend TOB, along with greater thorax peak speed during the downswing. Variables that were distinctive for the CHS model were mainly during the downswing: greater X-factor stretch; and higher pelvis peak speed. Finally, factors distinctive to the regression model for CD were: reduced thorax rotation; and greater thorax lateral bend. Implications from the results suggest whilst greater peak pelvis speed and x-factor stretch effect CHS they do not significantly influence CD. Likewise, the variables unique to CD do not significantly influence CHS but may be a technical attributes which allow for more optimal clubhead delivery leading to improved CD.

  • 33.
    Parker, James
    et al.
    Högskolan i Halmstad, Akademin för ekonomi, teknik och naturvetenskap, Bio- och miljösystemforskning (BLESS). 2Scandinavian School of Golf, Gothenburg, Sweden.
    Hellström, John
    Swedish Golf Federation, Stockholm, Sweden.
    Olsson, M. Charlotte
    Högskolan i Halmstad, Akademin för ekonomi, teknik och naturvetenskap, Bio- och miljösystemforskning (BLESS).
    The Relationship of the Lead Arm, Upper Torso, and Pelvis with Driver Club Head Speed Among Elite Golf Players2015Inngår i: International Journal of Golf Science, ISSN 2168-7595, Vol. 4, nr Suppl., s. S73-S75Artikkel i tidsskrift (Fagfellevurdert)
  • 34.
    Parker, James
    et al.
    Högskolan i Halmstad, Akademin för ekonomi, teknik och naturvetenskap, Rydberglaboratoriet för tillämpad naturvetenskap (RLAS). Scandinavian College of Sport, Gothenburg, Sweden.
    Lagerhem, Charlie
    Högskolan i Halmstad, Akademin för ekonomi, teknik och naturvetenskap.
    Hellström, John
    Högskolan i Halmstad, Akademin för ekonomi, teknik och naturvetenskap. Swedish Golf Federation, Stockholm, Sweden.
    Olsson, Charlotte M.
    Högskolan i Halmstad, Akademin för ekonomi, teknik och naturvetenskap, Rydberglaboratoriet för tillämpad naturvetenskap (RLAS).
    Effects of nine weeks isokinetic training on power, golf kinematics, and driver performance in pre-elite golfers2017Inngår i: BMC Sports Science, Medicine and Rehabilitation, ISSN 2052-1847, Vol. 9, artikkel-id 21Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Background

    It has previously been shown that isotonic strength training can improve driver performance among golfers, though few studies have investigated effects of strength training on swing kinematics together with driver performance. In this study we investigated whether isokinetic rotational training could improve driver performance and swing kinematic variables amongst elite golfers.

    Methods

    Twenty competitive pre-elite golfers (handicap better than −3.0), 13 men and 7 women, were split into two groups, one group received the isokinetic power training (IK) alongside their normal isotonic pre-season strength-training and the other group continued with their normal isotonic pre-season strength-training regime (IT). The IK group completed 12 sessions of isokinetic power training on a standing rotation exercise (10% body weight at 1 m/s) and barbell squat (25 kg plus 10% body weight at 0.5 m/s). The IT group continued with their normal isotonic pre-season strength-training regime. Participants were tested for rotational power, lower body power, golf swing kinematics, and driver performance before and after a nine-week training period.

    Results

    After the nine-week training period both the IK and the IT groups increased their dominant side rotational force and power (effect sizes between 0.50–0.96) and magnitude based inference indicated that IK had a likely (> 80%) more beneficial increase in dominant side rotational force and power. For swing kinematics, IK had a likely (> 80%) more beneficial improvement in lead arm speed and acceleration compared to the IT group. For driver performance, IK had a possible (65%) beneficial effect on ball speed and likely (78%) beneficial effect on carry distance when compared to IT, whereas neither of the groups improved club head speed.

    Conclusion

    In the present study on pre-elite golfers we found that 9 weeks of isokinetic training increased seated rotational force and power, peak arm speed and arm acceleration, ball speed, and carry distance more compared to isotonic training. Even though isokinetic training did not increase CHS, it did result in greater carry distance. © The Author(s). 2017

  • 35.
    Parker, James
    et al.
    Högskolan i Halmstad, Akademin för ekonomi, teknik och naturvetenskap, Bio- och miljösystemforskning (BLESS). Scandinavian School of Golf, Gothenburg, Sweden.
    Lagerhem, Charlie
    Högskolan i Halmstad, Akademin för ekonomi, teknik och naturvetenskap.
    Olsson, M Charlotte
    Högskolan i Halmstad, Akademin för ekonomi, teknik och naturvetenskap, Bio- och miljösystemforskning (BLESS), Biomekanik och biomedicin.
    Effects of 8 Weeks of Isokinetic Training on Power, Golf Kinematics, and Club Head Speed In Elite Golfers2015Konferansepaper (Annet vitenskapelig)
    Abstract [en]

    Introduction: Elite competitive golfers commonly use physical conditioning as a way of improving playing results. Multiple studies have investigated the use of different training methods for improving performance but few studies have investigated the use of isokinetic power training as a way of improving swing kinematics and/or club head speed (CHS). The specific objective of the study was to investigate if eight weeks of isokinetic power training was more effective than traditional power training in improving swing kinematics and CHS.

    Methods: 20 competitive elite golfers (handicap better than -3.1), 13 men and 7 women, (age 22±2 years) were tested for lower body power (countermovement jump and loaded vertical squat jump 20,40 & 60kg), rotational power (seated upper body rotational power at 10% of body weight; bw) and golf swing kinematics (pelvis, thorax and lead arm peak rotational velocities using electromagnetic motion capture system; Polhemus Inc. USA ) and club head speed (doppler-radar launch monitor system; Flightscope, South Africa), Participants were split into a control (CTL) group (n=10) who continued with the regular strength and power training and an intervention (IK) group (n=10) performing isokinetic power training in the isokinetic 1080Quantum system (1080Motion, Sweden) during 8 weeks. The intervention focused on barbell squat (22kg at 0.5 ms-1) and standing rotation (10% body weight at 1 ms-1).

    Statistical analysis: a 2 (between; groups) x 2 (within; time) ANOVA assessed any differences in power, club and swing kinematics.

    Results: Statistically significant improvements were observed in both the IK and CTL group for rotational power (p<0.001), CHS (p=0.025), and peak arm speed (p=0.001). There were no significant differences in countermovement jump height, peak power during squats, peak pelvis speed, or peak thorax speed following the intervention period.

    Discussion: After 8 weeks of power training, both rotational power and peak arm speed improved as did the performance measure of CHS in both the IK and CTL group. However no significant changes were found between the two groups. In conclusion, there was no evidence suggesting that isokinetic training, as performed in this study, is neither detrimental, nor more effective, than traditional strength training when it comes to increasing CHS in golf performance.

  • 36.
    Parker, James
    et al.
    Högskolan i Halmstad, Sektionen för ekonomi och teknik (SET), Bio- och miljösystemforskning (BLESS), Biomekanik och biomedicin.
    Olsson, Charlotte
    Högskolan i Halmstad, Sektionen för ekonomi och teknik (SET), Bio- och miljösystemforskning (BLESS), Biomekanik och biomedicin.
    Brorsson, Sofia
    Högskolan i Halmstad, Sektionen för ekonomi och teknik (SET), Bio- och miljösystemforskning (BLESS), Biomekanik och biomedicin.
    A One Year Study on Changes in Flexibility and Stability Characteristics in Elite Golfers2011Annet (Annet vitenskapelig)
    Abstract [en]

    The results from this study show that training strategies can lead to improved flexibility and stability in golfers during the off season, however maintaining these improvements, particularly flexibility, during the in-season is not as easy. Decreased flexibility on the left side leads to reduced ROM to manage deceleration of  forces produced in the golf swing that probably lead to an increased risk of injury. Significant improvements can be made after no more than 3 months of  training, including flexibility and stability training. Technique training may be more successful if it follows a period of concentrated physical training.  During the in-season, emphasis ought to be on maintaining ROM by effective implementation of stretching programs.

  • 37.
    Parker, James
    et al.
    Högskolan i Halmstad, Akademin för ekonomi, teknik och naturvetenskap, Bio- och miljösystemforskning (BLESS).
    Olsson, Charlotte
    Högskolan i Halmstad, Akademin för ekonomi, teknik och naturvetenskap, Bio- och miljösystemforskning (BLESS).
    Brorsson, Sofia
    Högskolan i Halmstad, Akademin för ekonomi, teknik och naturvetenskap, Bio- och miljösystemforskning (BLESS).
    Grip force and muscle activity are associated with kinematics in the golf swing2012Inngår i: Medicine & Science in Sports & Exercise, ISSN 0195-9131, E-ISSN 1530-0315, Vol. 44, nr Suppl. 2, s. 474-474Artikkel i tidsskrift (Fagfellevurdert)
  • 38.
    Parker, James
    et al.
    Högskolan i Halmstad, Akademin för ekonomi, teknik och naturvetenskap, Bio- och miljösystemforskning (BLESS), Biomekanik och biomedicin.
    Olsson, M Charlotte
    Högskolan i Halmstad, Akademin för ekonomi, teknik och naturvetenskap, Bio- och miljösystemforskning (BLESS), Biomekanik och biomedicin.
    Are There Stretch Shortening Cycle like Actions in the Shoulder and Torso in Upper Body Striking Actions2013Konferansepaper (Annet vitenskapelig)
  • 39.
    Petersson, Johan
    et al.
    Högskolan i Halmstad, Akademin för ekonomi, teknik och naturvetenskap.
    Riggberger, Kenneth
    Stadionkontoret, Malmö Sports Academy, Malmö, Sweden.
    Brorsson, Sofia
    Högskolan i Halmstad, Akademin för ekonomi, teknik och naturvetenskap, Rydberglaboratoriet för tillämpad naturvetenskap (RLAS).
    Olsson, Charlotte M.
    Högskolan i Halmstad, Akademin för ekonomi, teknik och naturvetenskap, Rydberglaboratoriet för tillämpad naturvetenskap (RLAS).
    Unilateral Strength Training With Maximal Velocity Improves Lower Body Power Outcome And Movement Velocity2012Inngår i: Medicine & Science in Sports & Exercise, ISSN 0195-9131, E-ISSN 1530-0315, Vol. 44, nr Suppl. 2, s. 671-671Artikkel i tidsskrift (Annet vitenskapelig)
  • 40.
    Razanskas, Petras
    et al.
    Kaunas University of Technology, Kaunas, Lithuania.
    Verikas, Antanas
    Högskolan i Halmstad, Akademin för informationsteknologi, Halmstad Embedded and Intelligent Systems Research (EIS), CAISR Centrum för tillämpade intelligenta system (IS-lab).
    Olsson, Charlotte
    Högskolan i Halmstad, Akademin för ekonomi, teknik och naturvetenskap, Bio- och miljösystemforskning (BLESS).
    Wiberg, Per-Arne
    Högskolan i Halmstad, Akademin för informationsteknologi, Halmstad Embedded and Intelligent Systems Research (EIS), CAISR Centrum för tillämpade intelligenta system (IS-lab).
    Time Domain Features of Multi-channel EMG Applied to Prediction of Physiological Parameters in Fatiguing Bicycling Exercises2015Inngår i: Frontiers in Artificial Intelligence and Applications, ISSN 0922-6389, E-ISSN 1879-8314, Vol. 278, s. 118-127Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    A set of novel time-domain features characterizing multi-channel surface EMG (sEMG) signals of six muscles (rectus femoris, vastus lateralis, and semitendinosus of each leg) is proposed for prediction of physiological parameters considered important in cycling: blood lactate concentration and oxygen uptake. Fifty one different features, including phase shifts between muscles, active time percentages, sEMG amplitudes, as well as symmetry measures between both legs, were defined from sEMG data and used to train linear and random forest models. The random forests models achieved the coefficient of determination R2 = 0:962 (lactate) and R2 = 0:980 (oxygen). The linear models were less accurate. Feature pruning applied enabled creating accurate random forest models (R2 >0:9) using as few as 7 (lactate) or 4 (oxygen) time-domain features. sEMG amplitude was important for both types of models. Models to predict lactate also relied on measurements describing interaction between front and back muscles, while models to predict oxygen uptake relied on front muscles only, but also included interactions between the two legs. © 2015 The authors and IOS Press. All rights reserved.

  • 41.
    Ražanskas, Petras
    et al.
    Kaunas University of Technology, Kaunas, Lithuania.
    Verikas, Antanas
    Högskolan i Halmstad, Akademin för informationsteknologi, Halmstad Embedded and Intelligent Systems Research (EIS), CAISR Centrum för tillämpade intelligenta system (IS-lab). Kaunas University of Technology, Kaunas, Lithuania.
    Olsson, Charlotte
    Högskolan i Halmstad, Akademin för ekonomi, teknik och naturvetenskap, Bio- och miljösystemforskning (BLESS).
    Wiberg, Per-Arne
    Swedish Adrenaline, Halmstad, Sweden.
    Predicting Blood Lactate Concentration and Oxygen Uptake from sEMG Data during Fatiguing Cycling Exercise2015Inngår i: Sensors, ISSN 1424-8220, E-ISSN 1424-8220, Vol. 15, nr 8, s. 20480-20500Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    This article presents a study of the relationship between electromyographic (EMG) signals from vastus lateralis, rectus femoris, biceps femoris and semitendinosus muscles, collected during fatiguing cycling exercises, and other physiological measurements, such as blood lactate concentration and oxygen consumption. In contrast to the usual practice of picking one particular characteristic of the signal, e.g., the median or mean frequency, multiple variables were used to obtain a thorough characterization of EMG signals in the spectral domain. Based on these variables, linear and non-linear (random forest) models were built to predict blood lactate concentration and oxygen consumption. The results showed that mean and median frequencies are sub-optimal choices for predicting these physiological quantities in dynamic exercises, as they did not exhibit significant changes over the course of our protocol and only weakly correlated with blood lactate concentration or oxygen uptake. Instead, the root mean square of the original signal and backward difference, as well as parameters describing the tails of the EMG power distribution were the most important variables for these models. Coefficients of determination ranging from R2 = 0:77 to R2 = 0:98 (for blood lactate) and from R2 = 0:81 to R2 = 0:97 (for oxygen uptake) were obtained when using random forest regressors.

  • 42.
    Ražanskas, Petras
    et al.
    Department of Electric Power Systems, Kaunas University of Technology, Kaunas, Lithuania.
    Verikas, Antanas
    Högskolan i Halmstad, Akademin för informationsteknologi, Halmstad Embedded and Intelligent Systems Research (EIS), CAISR Centrum för tillämpade intelligenta system (IS-lab). Department of Electrical Power Systems, Kaunas University of Technology, Lithuania.
    Viberg, Per-Arne
    Swedish Adrenaline, Halmstad, Sweden.
    Olsson, Charlotte M.
    Högskolan i Halmstad, Akademin för ekonomi, teknik och naturvetenskap, Rydberglaboratoriet för tillämpad naturvetenskap (RLAS).
    Predicting physiological parameters in fatiguing bicycling exercises using muscle activation timing2017Inngår i: Biomedical Signal Processing and Control, ISSN 1746-8094, E-ISSN 1746-8108, Vol. 35, s. 19-29Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    This article is concerned with a novel technique for prediction of blood lactate concentration level and oxygen uptake rate from multi-channel surface electromyography (sEMG) signals. The approach is built on predictive models exploiting a set of novel time-domain variables computed from sEMG signals. Signals from three muscles of each leg, namely, vastus lateralis, rectus femoris, and semitendinosus were used in this study. The feature set includes parameters reflecting asymmetry between legs, phase shifts between activation of different muscles, active time percentages, and sEMG amplitude. Prediction ability of both linear and non-linear (random forests-based) models was explored. The random forests models showed very good prediction accuracy and attained the coefficient of determination R2 = 0.962 for lactate concentration level and R2 = 0.980 for oxygen uptake rate. The linear models showed lower prediction accuracy. Comparable results were obtained also when sEMG amplitude data were removed from the training sets. A feature elimination algorithm allowed to build accurate random forests (R2 > 0.9) using just six (lactate concentration level) or four (oxygen uptake rate) time-domain variables. Models created to predict blood lactate concentration rate relied on variables reflecting interaction between front and back leg muscles, while parameters computed from front muscles and interactions between two legs were the most important variables for models created to predict oxygen uptake rate.© 2017 Elsevier Ltd.

  • 43.
    Rögnvaldsson, Thorsteinn
    et al.
    Högskolan i Halmstad, Akademin för informationsteknologi, Halmstad Embedded and Intelligent Systems Research (EIS).
    Brink, Joachim
    Högskolan i Halmstad.
    Florén, Henrik
    Högskolan i Halmstad, Akademin för ekonomi, teknik och naturvetenskap, Centrum för innovations-, entreprenörskaps- och lärandeforskning (CIEL).
    Gaspes, Veronica
    Högskolan i Halmstad, Akademin för informationsteknologi, Halmstad Embedded and Intelligent Systems Research (EIS).
    Holmgren, Noél
    University of Skövde, Skövde, Sweden.
    Lutz, Mareike
    Högskolan i Halmstad.
    Nilsson, Pernilla
    Högskolan i Halmstad, Akademin för lärande, humaniora och samhälle, Forskning om utbildning och lärande inom lärarutbildningen (FULL).
    Olsfelt, Jonas
    Högskolan i Halmstad.
    Svensson, Bertil
    Högskolan i Halmstad, Akademin för informationsteknologi, Halmstad Embedded and Intelligent Systems Research (EIS).
    Ericsson, Claes
    Högskolan i Halmstad, Akademin för lärande, humaniora och samhälle, Forskning om utbildning och lärande inom lärarutbildningen (FULL).
    Gustafsson, Linnea
    Högskolan i Halmstad, Akademin för lärande, humaniora och samhälle, Kontext & kulturgränser (KK).
    Hoveskog, Maya
    Högskolan i Halmstad, Akademin för ekonomi, teknik och naturvetenskap, Centrum för innovations-, entreprenörskaps- och lärandeforskning (CIEL).
    Hylander, Jonny
    Högskolan i Halmstad, Akademin för ekonomi, teknik och naturvetenskap, Bio- och miljösystemforskning (BLESS).
    Jonsson, Magnus
    Högskolan i Halmstad, Akademin för informationsteknologi, Halmstad Embedded and Intelligent Systems Research (EIS).
    Nygren, Jens
    Högskolan i Halmstad, Akademin för hälsa och välfärd, Centrum för forskning om välfärd, hälsa och idrott (CVHI).
    Rosén, Bengt-Göran
    Högskolan i Halmstad, Akademin för ekonomi, teknik och naturvetenskap, Maskinteknisk produktframtagning (MTEK).
    Sandberg, Mikael
    Högskolan i Halmstad, Akademin för lärande, humaniora och samhälle, Centrum för samhällsanalys (CESAM).
    Benner, Mats
    Lund University, Lund, Sweden.
    Berg, Martin
    Högskolan i Halmstad, Akademin för lärande, humaniora och samhälle, Centrum för samhällsanalys (CESAM).
    Bergvall, Patrik
    Högskolan i Halmstad.
    Carlborg, Anna
    Högskolan i Halmstad.
    Fleischer, Siegfried
    Högskolan i Halmstad, Akademin för ekonomi, teknik och naturvetenskap, Bio- och miljösystemforskning (BLESS).
    Hållander, Magnus
    Högskolan i Halmstad, Akademin för informationsteknologi, Halmstad Embedded and Intelligent Systems Research (EIS).
    Mattsson, Marie
    Högskolan i Halmstad, Akademin för ekonomi, teknik och naturvetenskap, Bio- och miljösystemforskning (BLESS).
    Olsson, Charlotte
    Högskolan i Halmstad, Akademin för ekonomi, teknik och naturvetenskap, Bio- och miljösystemforskning (BLESS).
    Pettersson, Håkan
    Högskolan i Halmstad, Akademin för informationsteknologi, Halmstad Embedded and Intelligent Systems Research (EIS).
    Rundquist, Jonas
    Högskolan i Halmstad, Akademin för ekonomi, teknik och naturvetenskap, Centrum för innovations-, entreprenörskaps- och lärandeforskning (CIEL).
    Sahlén, Göran
    Högskolan i Halmstad, Akademin för ekonomi, teknik och naturvetenskap, Bio- och miljösystemforskning (BLESS).
    Waara, Sylvia
    Högskolan i Halmstad, Akademin för ekonomi, teknik och naturvetenskap, Bio- och miljösystemforskning (BLESS).
    Weisner, Stefan
    Högskolan i Halmstad, Akademin för ekonomi, teknik och naturvetenskap, Bio- och miljösystemforskning (BLESS).
    Werner, Sven
    Högskolan i Halmstad, Akademin för ekonomi, teknik och naturvetenskap, Bio- och miljösystemforskning (BLESS).
    ARC13 – Assessment of Research and Coproduction: Reports from the assessment of all research at Halmstad University 20132014Rapport (Annet (populærvitenskap, debatt, mm))
    Abstract [en]

    During 2013, an evaluation of all the research conducted at Halmstad University was carried out. The purpose was to assess the quality of the research, coproduction, and collaboration in research, as well as the impact of the research. The evaluation was dubbed the Assessment of Research and Coproduction 2013, or ARC13. (Extract from Executive Summary)

  • 44.
    Stelzer, J E
    et al.
    Department of Physiology, Univ. of Wisconsin Medical School, Madison, WI 53706, United States.
    Patel, J R
    Department of Physiology, Univ. of Wisconsin Medical School, Madison, WI 53706, United States.
    Olsson, M Charlotte
    Department of Physiology, Univ. of Wisconsin Medical School, Madison, WI 53706, United States.
    Fitzsimons, D P
    Department of Physiology, Univ. of Wisconsin Medical School, Madison, WI 53706, United States.
    Leinwand, L A
    Dept. Molec., Cell., Devmtl. Biol., University of Colorado, Boulder, CO 80309, United States.
    Moss, R L
    Department of Physiology, Univ. of Wisconsin Medical School, Madison, WI 53706, United States.
    Expression of cardiac troponin T with COOH-terminal truncation accelerates cross-bridge interaction kinetics in mouse myocardium2004Inngår i: American Journal of Physiology. Heart and Circulatory Physiology, ISSN 0363-6135, E-ISSN 1522-1539, Vol. 287, nr 4, s. H1756-H1761Artikkel i tidsskrift (Fagfellevurdert)
  • 45.
    Sundström, Tomas
    et al.
    Högskolan i Halmstad, Akademin för ekonomi, teknik och naturvetenskap.
    Ronkainen, Fanny
    Högskolan i Halmstad, Akademin för ekonomi, teknik och naturvetenskap.
    Brorsson, Sofia
    Högskolan i Halmstad, Akademin för ekonomi, teknik och naturvetenskap, Bio- och miljösystemforskning (BLESS).
    Olsson, M. Charlotte
    Högskolan i Halmstad, Akademin för ekonomi, teknik och naturvetenskap, Bio- och miljösystemforskning (BLESS), Biomekanik och biomedicin.
    Five Weeks of Plyometric Training Improve Vertical Jump Height in Female Handball Players During In-Season2010Inngår i: Nordic Conference 2010: Abstracts / [ed] Karen Søgaard, Karsten Froberg & Mette Krogh Christensen, Odense: University of Southern Denmark , 2010, s. 112-113Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Introduction: Handball is a sport requiring many different physical qualities in order to perform well, one of which is good jumping ability. For handball players available time to enhance power during in-season is often restricted due to an already high training load emphasizing other aspects of the sport than jumping ability. Therefore, one aim of this study was to examine if a small amount of additional plyometric training during in-season, combining drop jumps and box jumps, could give significant improvements in vertical jump height in female handball players after five weeks of training. Generally, vertical jump height is evaluated with two-legged tests, however, the question arises if the tests are relevant in sports that predominantly use several steps and one-leg jumps such as handball. A second aim of this study was thus to develop, evaluate and validate a handball-specific test performed on one leg.

    Methods: Two Swedish female handball-teams playing in the third division were recruited. Players from one team made up the intervention-group (n = 9) and players from the other team functioned as the control-group (n = 4). Plyometric training was added to the regular handball training session twice per week during five weeks, lasting approximately 15 minutes per session, consisting of two sets of eight repetitions of drop jumps and box jumps respectively, while the control-group continued their training as normal. Jumping performance was evaluated through the squat jump test (SJ), countermovement jump test (CMJ) and the handball-specific one leg jump test (OLJ) developed for this study in order to offer a more sport-specific evaluation tool when testing sports that predominantely jump on one leg.

    Results: The intervention-group improved their jumping height significantly with 2,7 cm in the SJ, 3,6cm in the CMJ and 3,6 cm in the OLJ (p < 0,01 for all). The control-group had an opposite trend with diminishing results in all three jumps, -1,5 cm in the SJ (p < 0,05), -1,7 cm in the CMJ (p < 0,05) and -0,9 cm in the OLJ (not significant). The one-legged jump test (OLJ) correlated well with both SJ (r= 0,79, p <0,01 ), and CMJ (r=0,75, p < 0,01).

    Discussion: The present study found significant improvements in jumping height after only five weeks of plyometric training for female handball players. Interestingly, the intervention-group improved to the same extent in both the one and the two-leg jumps test, which might be explained by the accumulation of handball specific training drills performed on one-leg, together with the two-legged plyometric exercises. The same assumption could also explain why the control-group showed no change in the one-leg jump test between the pre and post-tests, but displayed significant lower scores in the two-legged jumping tests after 5 weeks with only regular handball training.

    Conclusion: The improvements seen in this study with a small amount of additional plyometric training is relevant for coaches that need to provide gains in jumping performance during in-season when there is not a lot of time for additional training. Moreover, an evaluation test needs to be as specific as possible to the performance in the sport. The one-leg vertical jump test, developed in this study, could be a first step to a future handball-test that better resembles the jumping performance in handball than already established two-leg jumping tests.

  • 46.
    Verikas, Antanas
    et al.
    Högskolan i Halmstad, Akademin för informationsteknologi, Halmstad Embedded and Intelligent Systems Research (EIS), CAISR Centrum för tillämpade intelligenta system (IS-lab). Kaunas University of Technology, Kaunas, Lithuania.
    Parker, James
    Högskolan i Halmstad, Akademin för ekonomi, teknik och naturvetenskap, Rydberglaboratoriet för tillämpad naturvetenskap (RLAS).
    Bacauskiene, Marija
    Kaunas University of Technology, Kaunas, Lithuania.
    Olsson, M. Charlotte
    Högskolan i Halmstad, Akademin för ekonomi, teknik och naturvetenskap, Rydberglaboratoriet för tillämpad naturvetenskap (RLAS).
    Exploring relations between EMG and biomechanical data recorded during a golf swing2017Inngår i: Expert systems with applications, ISSN 0957-4174, E-ISSN 1873-6793, Vol. 88, s. 109-117Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Exploring relations between patterns of peak rotational speed of thorax, pelvis and arm, and patterns of EMG signals recorded from eight muscle regions of forearms and shoulders during the golf swing is the main objective of this article. The linear canonical correlation analysis, allowing studying relations between sets of variables, was the main technique applied. To get deeper insights, linear and nonlinear random forests-based prediction models relating a single output variable, e.g. a thorax peak rotational speed, with a set of input variables, e.g. an average intensity of EMG signals were used. The experimental investigations using data from 16 golfers revealed statistically significant relations between sets of input and output variables. A strong direct linear relation was observed between lin- ear combinations of EMG averages and peak rotational speeds. The coefficient of determination values R2 = 0 . 958 and R2 = 0 . 943 obtained on unseen data by the random forest models designed to predict peak rotational speed of thorax and pelvis , indicate high modelling accuracy. However, predictions of peak rotational speed of arm were less accurate. This was expected, since peak rotational speed of arm played a minor role in the linear combination of peak speeds. The most important muscles to predict peak rotational speed of the body parts were identified. The investigations have shown that the canon- ical correlation analysis is a promising tool for studying relations between sets of biomechanical and EMG data. Better understanding of these relations will lead to guidelines concerning muscle engagement and coordination of thorax, pelvis and arms during a golf swing and will help golf coaches in providing substantiated advices. ©2017 Elsevier Ltd. All rights reserved.

  • 47.
    Verikas, Antanas
    et al.
    Högskolan i Halmstad, Akademin för informationsteknologi, Halmstad Embedded and Intelligent Systems Research (EIS), CAISR Centrum för tillämpade intelligenta system (IS-lab). Kaunas University of Technology, Kaunas, Lithuania.
    Vaiciukynas, Evaldas
    Kaunas University of Technology, Kaunas, Lithuania.
    Gelzinis, Adas
    Kaunas University of Technology, Kaunas, Lithuania.
    Parker, James
    Högskolan i Halmstad, Akademin för ekonomi, teknik och naturvetenskap, Bio- och miljösystemforskning (BLESS).
    Olsson, M. Charlotte
    Högskolan i Halmstad, Akademin för ekonomi, teknik och naturvetenskap, Bio- och miljösystemforskning (BLESS).
    Electromyographic Patterns during Golf Swing: Activation Sequence Profiling and Prediction of Shot Effectiveness2016Inngår i: Sensors, ISSN 1424-8220, E-ISSN 1424-8220, Vol. 16, nr 4, artikkel-id 592Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    This study analyzes muscle activity, recorded in an eight-channel electromyographic (EMG) signal stream, during the golf swing using a 7-iron club and exploits information extracted from EMG dynamics to predict the success of the resulting shot. Muscles of the arm and shoulder on both the left and right sides, namely flexor carpi radialis, extensor digitorum communis, rhomboideus and trapezius, are considered for 15 golf players (∼5 shots each). The method using Gaussian filtering is outlined for EMG onset time estimation in each channel and activation sequence profiling. Shots of each player revealed a persistent pattern of muscle activation. Profiles were plotted and insights with respect to player effectiveness were provided. Inspection of EMG dynamics revealed a pair of highest peaks in each channel as the hallmark of golf swing, and a custom application of peak detection for automatic extraction of swing segment was introduced. Various EMG features, encompassing 22 feature sets, were constructed. Feature sets were used individually and also in decision-level fusion for the prediction of shot effectiveness. The prediction of the target attribute, such as club head speed or ball carry distance, was investigated using random forest as the learner in detection and regression tasks. Detection evaluates the personal effectiveness of a shot with respect to the player-specific average, whereas regression estimates the value of target attribute, using EMG features as predictors. Fusion after decision optimization provided the best results: the equal error rate in detection was 24.3% for the speed and 31.7% for the distance; the mean absolute percentage error in regression was 3.2% for the speed and 6.4% for the distance. Proposed EMG feature sets were found to be useful, especially when used in combination. Rankings of feature sets indicated statistics for muscle activity in both the left and right body sides, correlation-based analysis of EMG dynamics and features derived from the properties of two highest peaks as important predictors of personal shot effectiveness. Activation sequence profiles helped in analyzing muscle orchestration during golf shot, exposing a specific avalanche pattern, but data from more players are needed for stronger conclusions. Results demonstrate that information arising from an EMG signal stream is useful for predicting golf shot success, in terms of club head speed and ball carry distance, with acceptable accuracy. Surface EMG data, collected with a goal to automatically evaluate golf player’s performance, enables wearable computing in the field of ambient intelligence and has potential to enhance exercising of a long carry distance drive.

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