Explosive rotational movements are parts of many sports such as golf, tennis and baseball. Rotational strength and power tests exist, but valid and reliable tests to measure standing rotational strength and standing rotational power are lacking. 1080 Quantum is a machine wich can measure, speed, force and power and has several different resistance modes was used for testing rotational power and strength in this study. Aim: The aim was to investigate the validity and reliability of two new standing Quantum rotational tests; one measuring maximal rotational strength (1RM) and one measuring rotational power. Methods: Fifteen subjects, 8 men and 7 women, with at least one year of experience of resistance training participated in the study. The two new tests were: the Quantum power rotational test (PRT) and the Quantum 1RM rotational test (1RMRT). Testing occured during two sessions and during the first session construct validity of the two new rotational tests was assessed with a standing medicine ball throw (MB) and a sitting rotational power test (SRT). During the second session PRT and 1RMRT were tested for test-retest reliability. To study construct validity á priori hypothesis were stated and data were analyzed with Spearman´s correlation coefficent (r_s). Intra correaltion coefficient (ICC) was used for test-retest reliability for PRT and 1RMRT. Results: Priori hypotheses were all fullfilled. Correlations found were considered good between PRT and MB (r_s=0.80), moderate between PRT and SRT (r_s=0.52), excellent between 1RMRT and MB (r_s=0.90), moderate between 1RMRT and SRT (r_s=0.73) and good between PRT and 1RMRT (r_s=0.81). Excellent test-retest reliability was found for PRT (ICC=0.94, 95% CI (0.80-0.99)) and 1RMRT (ICC=0.98, 95% CI (0.92-0.99)) Conclusion: The two new rotational tests performed in 1080 Quantum both assessed construct validity and test-retest reliability. PRT can be used to measure standing rotational power and 1RMRT can be used to measure standing rotational maximum strength.

Abstract

Background: The ability to produce a high power output can be the deciding factor in determining which athlete wins or loses in a sporting event. Power output can be measured in an exercise like the squat or bench press. The use of a force plate, or a force plate paired with a linear position transducer is considered the gold standard when measuring power output in an exercise like the squat or bench press. Linear position transducers or linear encoders have also been considered valid methods. Power output can also be measured by accelerometers.

Purpose: The purpose of this study was to test the concurrent validity of the accelerometer Beast Sensor by measuring average power in explosive squatting and bench pressing at 40 % and 80 % of one repetition maximum (1RM). The linear encoder MuscleLab was used as criterion.

Methods: 17 test subjects, five women and 12 men (average age 28 years) were recruited. Fifteen of the subjects completed two test sessions. The first session determined their 1RM. The second session took place 7-14 days later and measured average power output during two sets of three repetitions at 40 % and 80 % of the subjects 1RM in explosive squats and bench presses. The average power output of the repetitions was measured simultaneously by Beast Sensor and MuscleLab. For the Beast Sensor to be considered valid, a correlation coefficient of 0.9 or higher needed to be reached.

Results: Beast Sensor demonstrated high or very high correlations with MuscleLab for average power output of explosive squats at 40 % of 1RM (r_s = 0.91), and for explosive bench presses at 40 % (r_s = 0.86) and 80 % of 1RM (r_s = 0.74). However, for explosive squats at 80 % of 1RM, the correlation was low (r_s = 0.42). All correlations were statistically significant with p-values of < 0.01. Beast Sensor was considered valid for squats at 40 % of 1RM, but neither at 80 % of 1RM in squats, nor at 40 % or 80 % of 1RM in bench presses.

Conclusion: Beast Sensor showed high or very high correlations with the criterion MuscleLab in three of the four assessed data variables. Only the correlation for average power output of the explosive squats at 40 % of the subject’s 1RM reached the required correlation coefficient of 0.9 or higher for the Beast Sensor to be considered valid. Except for at 40 % of 1RM in squats, Beast Sensor missed a substantial amount of repetitions. Further studies examining the reliability of the Beast Sensor are therefore needed. 

För att kunna prestera bra under fysiskt krävande ishockeymatcher krävs det att spelarna harhög maximal benstyrka och en hög explosiv förmåga. Bilaterala knäböj är en erkänd och välspridd övning för att förbättra power och muskelstyrka i benen. Unilaterala knäböj är än mersportspecifika för ishockeyn. Vid en isokinetisk rörelse är hastigheten förutbestämd ochdärmed konstant medan kraften kan förändras under rörelsen. De flesta isokinetiska systemhar varit designade för unilaterala isolerade övningar, men gällande isokinetiskaflerledsövningar så som knäböj tycks det inte finnas någon forskning om i nuläget.Studiens syfte var att undersöka effekten av sex veckors unilateral styrketräning (knäböj),antingen genom traditionell eller genom isokinetisk träning, på power i unilaterala ochbilaterala jump squats och 17.3 m sprinttid på is hos manliga juniorishockeyspelare.20 manliga ishockeyspelare på elitnivå, 18-19 år gamla, delades slumpmässigt in i två olikaträningsgrupper. Den ena gruppen (QG) utförde isokinetiska unilaterala knäböj i 1080Quantum med 110o vinkel i knäleden, medan den andra gruppen (SG) utförde traditionellaunilaterala knäböj i Smithmaskin med 110o vinkel i knäleden. Träningsperioden varade undersex veckor. Båda grupperna genomförde för- och eftertester bestående av sprinttest på is ochpeak power för unilaterala och bilaterala jump squats.QG visar en signifikant förbättring i peak power utfört på två ben (p=0,004). SG visar ensignifikant förbättring i unilaterala knäböj utfört på höger ben (p=0,018). QG hade en tendenstill signifikant förbättring i issprint (p=0,059).Isokinetiska unilaterala knäböj i Smithmaskin med en koncentrisk hastighet på 0,2meter/sekund och en excentrisk hastighet på maximalt 4,0 meter/sekund och en maximalkraftinsats är ett effektivt sätt att förbättra power på två ben och eventuellt också för attförbättra sprinthastigheten vid issprint för ishockeyspelare. Om isokinetiska unilaterala knäböjär en effektivare metod för att förbättra power jämfört med traditionella unilaterala knäböj iSmithmaskin med maximal hastighet är det svårt att dra slutsatser om från denna studiesresultat.

Background. Parkour is a sport which has developed its own landing technique, precision landing (PL), which has shown to reduce vertical ground reaction forces (vGRF) in comparison to a more traditional landing (TL). However previous studies lacks control for intra group knee flexion between the TL and PL techniques. Aim. The aim of this study was to analyse the biomechanical differences between a parkour precision landing with a traditional landing in four knee flexion groups (Stiff landing (SL), 25-50o, 50-75o and 75-100o), comparing vGRF, time to peak force and average rate of force development (avgRFD) between both landing techniques within each group as well as between the groups. Method. 42 participants were recruited to participate in a single session of a randomized, experimental study. Participants were randomly placed into one of four groups and performed a practice session of the two different landing techniques at the knee flexion angle given. All participants performed 5 approved landings with a TL technique and thereafter 5 approved landing using PL. Results. A significant increase of vGRF was found with TL compared to PL within all groups (p ≤ 0.05). Reduced time to peak force and increased avgRFD was found in TL compared to PL across all groups (p = 0.01) with the exception of 25-50o (p = 0.27 for time to peak force and p = 0.73 for avgRFD). Conclusion. The results of current study shows that PL reduces vGRF, time to peak force and avgRFD compared to TL in recreationally trained individuals. The results varied when compared between knee flexion groups, however results shows that 50-75o seems to be the more optimal range of knee flexion in terms of reducing ground reaction forces.

Background: A squat is a common exercise that is used in many areas of strength training and for different purposes and the literature is inconclusive when it comes to whether the weight lifting belt (WB) affects performance and/or is injury-preventing. The use of breathing techniques is common during heavy lifting and therefore the practice of the breathing teqnice; valsalva maneuver (VM) may be of interest to study and if this along with the WB can provide some advantages in power output and velocity. Aim: The specific aim of the study was to evaluate whether the velocity in the eccentric and the concentric phase of the squat, and the peak velocity in the concentric phases are affected in power output through the use of the VM when the subjects use or did not use a WB. Method: Fifteen subjects (10 men and 5 women) volunteered freely to participate and did a total of 12 squats divided in four different sets with three repetitions each on 75% of their self-reported one repetition maximum (1RM). The first two sets were either with or without WB and the third and fourth sets were either with or without the practice of the VM. The three conditions (with WB, with WB + VM and VA only) were compared to each other and to the control group (without any instructions and no WB) in terms of power output and velocity in the eccentric, concentric and peak velocity in the concentric phase of the squat. Result: There was no significant difference in power output when comparing the four different test conditions. The velocity in the eccentric, concentric and peak velocity in the concentric phase did not have a significant difference between the different test conditions. Conclusions: This study shows a different output compared to previous literature. The WB and the practice of VM did not affect the power output and velocity in a squat, alone or together. 

Background: To learn how to swim with proper technique takes fairly large amount of time and practice to learn and anelite swimmer spends 6-7 days training for improving aerobic capacity, anaerobic capacity and strength training for energy saving technique. Freestyle is the fastest swimming style and is performed in many different distances, 50m is classified as a sprint and the 400m as a middle-distance. The research is inconclusive if there is a correlation in the lower body and the time in 50m and 400m and mostly in the middle distance which gives this study the importance reducing these uncertainties. Aim: The aim of this study was to determine the strength of the correlation between the upper- and lower body muscle strengthwith time in 50m and 400m freestyle and to analyze which of the variables of height, sex, upper- and lower body strength contribute to velocity in sprint and middle distance in competitive swimmers. Method:A total of 14 participants (3 men and 11 women) participated in the study. The participants were tested at three occasions. The first was to determine their three-repetition maximum (3RM) in the squat and lat-pulldown. The second occasion was the collection the time in 50m freestyle and the third was to collect the time in 400m freestyle. Relative strength (kg/kg BW; %) and absolute strength (kg) in 1RM was calculated and correlated with the time in 50m and 400m freestyle. Analysis was done to see which variables of height, sex, relative strength in the squat and lat-pulldown contribute the most to the time in freestyle. Result: The result show that there was a high correlation between the absolute strength in the squat and the time in 50m (r=-0.769) a moderate correlation in the absolute strength in lat-pulldown and the 50m freestyle sprint (r=-0.513). There was also a moderate correlation for the relative strength in the lat-pulldown and 50m freestyle (r=-0.599). The 400m correlate with the relative strength in both lat-pulldown(r=-0.563) and the squat (r=-0.555). The lat-pulldown contributed most to the time in 50m freestyle as well as the male sex. Conclusions: The absolute strength in the squat had a high correlation to the time in 50m freestyle swim. The 400m there was a moderate correlation to the relative strength in the squat and lat-pulldown showing that for the overall performance in middle-distance the relative strength has the advantage over absolute strength. The relative and absolute strength in upper body correlated to both 50m and 400m freestyle and could therefore strengthen the importance of upper body strength in sprint and middle distance as previous researchers has stated. The upper body strength is the best predictor of time in 50m.

Myocellular stress with high-frequency blood flow restricted resistance exercise (BFRRE) was investigated by measures of heat shock protein (HSP) responses, glycogen content and inflammatory markers. Thirteen participants (24±2 years [mean±SD], 9 males) completed two 5-day-blocks of 7 BFRRE sessions, separated by 10 days. Four sets of unilateral knee extensions to failure at 20% of 1RM were performed. Muscle samples obtained before, 1h after the first session in the first and second block ("Acute1" and "Acute2"), after 3 sessions ("Day4"), during the "Rest Week", and at 3 ("Post3") and 10 days post-intervention ("Post10"), were analyzed for HSP70, αB-crystallin, glycogen (PAS staining), mRNAs, miRNAs, and CD68+ (macrophages) and CD66b+ (neutrophils) cell numbers. αB-crystallin translocated from the cytosolic to the cytoskeletal fraction after Acute1 and Acute2 (p<0.05), and immunostaining revealed larger responses in type I than type II fibers (Acute1, 225±184% vs. 92±81%, respectively, p=0.001). HSP70 was increased in the cytoskeletal fraction at Day4 and Post3, and immunostaining intensities were more elevated in type I than in type II fibers at Day4, (206±84% vs. 72±112%, respectively, p<0.001), during the Rest Week (98±66% vs. 42±79%, p<0.001) and at Post3 (115±82% vs. 28±78%, p=0.003). Glycogen content was reduced in both fiber types; but most pronounced in type I, which did not recover until the Rest Week (-15-29%, p≤0.001). Intramuscular macrophage numbers were increased by ~65% post-intervention, but no changes were observed in muscle neutrophils. We conclude that high-frequency BFRRE with sets performed till failure stresses both fiber types, with type I fibers being most affected. © 2021 the American Physiological Society

The effects of long‐term physical inactivity on the expression of microRNAs involved in the regulation of skeletal muscle mass in humans are largely unknown. MicroRNAs are short, noncoding RNAs that fine‐tune target expression through mRNA degradation or by inhibiting protein translation. Intronic to the slow, type I, muscle fiber type genes MYH7 and MYH7b, microRNA‐208b and microRNA‐499‐5p are thought to fine‐tune the expression of genes important for muscle growth, such as myostatin. Spinal cord injured humans are characterized by both skeletal muscle atrophy and transformation toward fast‐twitch, type II fibers. We determined the expression of microRNA‐208b, microRNA‐499‐5p, and myostatin in human skeletal muscle after complete cervical spinal cord injury. We also determined whether these microRNAs altered myostatin expression in rodent skeletal muscle. A progressive decline in skeletal muscle microRNA‐208b and microRNA‐499‐5p expression occurred in humans during the first year after spinal cord injury and with long‐standing spinal cord injury. Expression of myostatin was inversely correlated with microRNA‐208b and microRNA‐499‐5p in human skeletal muscle after spinal cord injury. Overexpression of microRNA‐208b in intact mouse skeletal muscle decreased myostatin expression, whereas microRNA‐499‐5p was without effect. In conclusion, we provide evidence for an inverse relationship between expression of microRNA‐208b and its previously validated target myostatin in humans with severe skeletal muscle atrophy. Moreover, we provide direct evidence that microRNA‐208b overexpression decreases myostatin gene expression in intact rodent muscle. Our results implicate that microRNA‐208b modulates myostatin expression and this may play a role in the regulation of skeletal muscle mass following spinal cord injury. © 2015 The Authors

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 (R_p= -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 (R_p=-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.

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 (r_p = 0,33 ; p = 0,23) or grip strength and submaximal strength test (r_p = 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.

Background: Physiologic functional capacity through maximal oxygen uptake (V̇O_2max) can be measured in many different ways depending on sport and qualities needed to be assessed.In handball a demanding 3000 meter (m) running test is used to evaluate V̇O_2max. If this test is sport specific or if it could be replaced by a less strenuous test is unknown. Aim: The aim ofthis study was to compare performance on 3000-meter running with predicted V̇O_2max from a submaximal treadmill jogging test (SMTJ) and performance of the Yo-Yo intermittentrecovery test 1 (IR1). Methods: Male handball players (n = 12) performed the 3000 m running test, the Submaximal Treadmill Jogging test and the Yo-Yo Intermittent Recovery test level 1. Measurements in seconds (s), ml ∙ kg^-1 ∙ min^-1 and meters where collected and correlated using Pearson r, interclass correlation. Results: A strong significant linear correlation (p < 0.01) was found between performance in 3000 m running (s) and Yo-Yo IR1 performance (m), r = - 0.724 (r2 = 0.524). A weak, not significant linear correlation (p > 0.05)was found between performance in 3000 m running (s) and predicted V̇O_2max from submaximal treadmill test (ml ∙ kg^-1 ∙ min^-1), r = - 0.309 (r2 = 0.095). Conclusion: According to this study the 3000 m running test could be replaced by the Yo-Yo IR1 test or vice versa in adolescent male handball players. The submaximal treadmill test used in this study had several potential errors in estimating V̇O_2max, this is probably the reason why only a weak correlation was found between the SMTJ and the 3000 m running test.

The relationship between birth quarter distribution and physiological characteristics related to athletic skills, in adolescent sport academy students has not been fully investigated. In a cross-sectional study, we recruited 86 boys and 52 girls aged 12-14 years during their first term at a sport academy school. We measured body size, cardiac size, pulmonary function, body composition, lower body power, cardiorespiratory fitness parameters, and running endurance by standard methods and analyzed these estimates in relation to birth quarter by ANOVA. Birth quarter distribution in our cohort was compared with birth quarter distribution in the same ages in the whole of Sweden and analyzed by logistic regression. The academy had an overrepresentation of students born in the first quartile of the year compared to those born in the last quartile (odds ratio 2.3 (95% CI: 1.1-4.7)). When comparing the physiological characteristics between birth quarters, uniformity is prominent since out of 26 performed physiological and anthropometric tests only four showed statistically significant group differences. We thus believe that the selection process to the sport academy favours athletes with higher chronological age, i.e., a so-called relative age effect is present. © 2020 MDPI (Basel, Switzerland).

Background: Working within the military as a ground combat solider is very physically demanding. Soldiers are required to handle situations ranging from peacekeeping to counterinsurgency and combat, while faced with the task of load carriage either in form of the military gear or other additional loads. Therefore, a good aerobic and anaerobic fitness is necessary. The aerobic and anaerobic fitness can be assessed with a wide range is methods such as measuring the peak oxygen uptake (VO2peak), ventilator threshold, blood lactate concentration and heart rate. However research is rather spares regarding the effects of load carriage on the aerobic capacity.

Aim: The aim of the current study was to investigate if military gear affects VO2peak, ventilatory threshold, blood lactate concentration and heart rate in ground combat soldiers.

Methods: A total of eight soldiers (seven men and one woman) participated in the current study. All participants completed two biological calibrations and VO2max tests (one without and one with military gear) using a modified Bruce protocol, where VO2 (L/min), absolute and relative VO2peck (L/min and ml/kg/min respectively), heart rate (beats/min) and blood lactate concentration (mM/L) were assessed. After the completion of the tests, the soldier’s individual ventilatory threshold (VT) was visually located using the V-slope method. The Wilcoxon test was used for the not normally distributed variables (blood lactate concentration and stage when VT occurred) and the paired sample t-test for the others. The significance level was set to 0.05.

Results: The results showed that the soldier had 10.6 % lower absolute VO2peak and 23.7 % lower relative VO2peak while wearing military gear compared to without (p=0.002 and p=0.001 respectively). The soldiers also had 11.8 % higher VO2 at VT with military gear (p=0.003) and reached a higher percentage of the VO2peak (p=0.023) at VT. The blood lactate concentration was significantly higher when marching at 5.4 km/h and a trend of a higher blood lactate concentration while standing was observed without military gear compared to with military gear.

Conclusion: The findings from the present study shows that performing load carriage in form of the military gear significantly decreased the VO2peak. Wearing a military gear also increased the VO2 at the individual VT and made the soldier reach a higher percentage of the VO2peak at VT. These results can act as guidance when recruiting and training soldiers, along with providing important information to other professions and sports that involve load carriage. 

Abstract

Background: Using a weight lifting belt when performing a variety of resistance exercises is becoming more and more common. The purpose of using a weight lifting belt is its supposed ability to reduce compressive forces on the lumbar spine and enhancement of athletic performance. Although the weight lifting belt has been proven to increase the intra abdominal pressure that helps reduces the shear forces during a squat, little is known about the weight lifting belts effect on the performance.

Studies have suggested that wearing a weight lifting belt during a squat can increase the vertical velocity and range of motion. Few studies have focused on the power output, but improvements have been seen while wearing a weight lifting belt when performing a deadlift. Variables such as power, velocity and range of motion are of importance for an athlete when making individual training plans as well as measuring the progress. Therefore more research is needed to identify the actual influence of the weight lifting belt on the performance.

Aim: The purpose of this study was to examine if weight lifting belts have an impact on an athletes ability to develop power, velocity or improve range of motion in a squat.

Methods: Fifteen healthy men and women familiar with the squat exercise participated in the study. During the study they performed six repetitions of the squat divided into two sets, one set without a weight lifting belt and one with a weight lifting belt. Power and velocity were measured during every squat with a linear encoder and videotapes were made to later calculate the angles in the hip- and knee joints at the lowest position of the exercise.

Results: No significant differences were found in power (p = 0.25) or concentric and eccentric velocity (p = 0.61, p = 0.16) with or without a weight lifting belt. Range of motion in the knee joint was greater when not wearing a weight lifting belt (p = 0.03), but no differences in the hip angles were found (p = 0.70).

Conclusion: The result from the current study shows that when performing a squat the weight lifting belt has little to no effect on power, velocity or range of motion. Although a noticeable change in range of motion of the knee joint were observed, further studies on larger populations are needed to determine if it is of clinical value. 

Sammanfattning

Bakgrund: Dagens stillasittande livsstil med ökat intag av energigivande ämnen resulterar i ett konstant anabolt hormonellt påslag. Detta leder till ökad övervikt och andra välfärdssjukdomar. Det rekommenderas att individer håller sig till en hög måltidsfrekvens med jämna mellanrum under dagen. Detta har börjat ifrågasättas med konkurrerande alternativ som involverar en tidigare samhällslivsstil så långt som 10 000 år sedan, då måltidsfrekvensen inte kunde planeras på samma sätt som idag.

Syfte: Syftet är att under sju veckor undersöka effekten av två stycken veckovisa 24-timmars periodiska förbud mot intag av energigivande ämnen, med implementering av fysisk styrketräning och dess effekt på lean body mass (LBM) och fettvikt hos yngre individer.

Metod: Två separata 24-timmars perioder av fasta i samband med tre separata styrketräningstillfällen genomfördes per vecka under sju veckor. Kroppsmått gällande kroppsfett i procent, fettvikt i kilogram (kg), kroppsdimensioner i centimeter (cm), LBM och total kroppsvikt i kg togs innan och efter studiens genomförande. Sju deltagare (två män och fem kvinnor) slutförde sitt deltagande i studien.

Resultat: Samtliga deltagare ökade i LBM, med en medelökningen på 1,3 kg. Den största ökningen var 2,6 kg, och återfanns hos två deltagare. Samtliga deltagare minskade sitt procentuella kroppsfett. Den högsta minskningen var 4,8 %, den lägsta minskningen var 1 %. Medelminskningen i fettvikt var 2 kg hos individerna. Den största minskningen av fettvikt var 4,2 kg, och den lägsta minskningen var 0,64 kg.

Slutsats: Periodisk fasta under två stycken 24-timmarsperioder per vecka kan fungera som ett verktyg för att minska fettprocent/fettvikt och samtidigt öka muskelmassan om det görs i kombination med tre stycken styrketräningstillfällen under samma vecka. Denna slutsats ifrågasätter äldre forskning och påståenden om vikten vid att hålla en hög och jämn måltidsfrekvens.

Background: Chronic pain is defined as pain for at least 3 months and is highly prevalent in society (10-30%). Individuals with chronic pain are more sensitive to pressure pain and have a disturbed pain perception. Physical activity (PA) has been shown to be a helpful method to treat and decrease disability in these individuals, but the knowledge about the relationship between chronic pain, PA and aerobic capacity is less understood. The aim of this study was to investigate if pain experience is associated with aerobic capacity and physical activity in a population with chronic pain in comparison to a pain free reference group.

Method: 146 men and women between 40 and 70 years old participated. Pressure pain sensitivity was measured with an Algometer on eight points and aerobic capacity was measured with Ekblom-Bak submaximal test on a bicycle ergometer. A questionnaire was used to gather information about self-reported PA, pain regions and fear-avoidance.

Result: Individuals with chronic pain had significantly lower pain thresholds (p=0.028) and higher fear-avoidance score (p=0.001), but no difference in aerobic capacity compared to pain-free individuals (p=0.344). Women had lower thresholds compared to men in both chronic pain and pain-free group (p<0.001 and p=0.008). There were no association between aerobic capacity and self-reported moderate PA (r=0.001) or in vigorous PA (r=0.173). Low VO_2max has more pain regions (p=0.017) and lower pain thresholds (p=0.001) compared with high VO_2max, but no difference in fear-avoidance score (p=0.234).

Conclusion: Individuals with chronic pain had a higher sensitivity to pressure pain and a higher fear-avoidance compared to pain-free individuals, but no difference in aerobic capacity. There were no associations between self-reported PA and aerobic capacity, and individuals with low VO_2max had more pain regions and lower pain thresholds compared with individuals with high VO_2max, but no differences in fear-avoidance was found.

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

Background Compression garments have gained interest over the past ten years, especially when investigating the recovery from a strenuous strength session. Since compression garments have increased in popularity over the past years, scientific results regarding possible benefits are still lacking. 

Aim The aim of the current study was to investigate the recovery from an eccentric exercise session with regards to physiological performance and perceived feelings of muscle soreness, fatigue and recovery in recreational athletes after wearing customized compression garments for 24-hours.

Method Thirteen recreational athletes (age 24.7±4.0 years (mean ± SD), length 171.3±7.0 cm, weight 70.8±9.4 kg), participated in this randomized crossover designed study. After a familiarization trial, participants completed two rounds of testing and exercise in both a control (CON) and a compression condition (CG). Garments were worn for 24-hours post exercise in the compression condition whereas regular clothing were used in the control condition. Performance variables of Wingate Anaerobic cycle Test, agility t-test and broad jump were assessed as well as subjective feelings of muscle soreness, both at baseline and 24-hours post a lower body eccentric exercise session.

Results Muscle soreness was significantly higher 24 hours post recovery (p=0.02) compared to baseline but no difference was seen between groups (p>0.05). There was a significant difference in perceived recovery (increased in CG, p=0.012) and fatigue (increased in CON, p=0.04) between conditions 24-hours post recovery. Physiological performance measured with Wingate, agility t-test and broad jumps were not different among either group or time (p>0.05). Perceived sleep quality was not different from pre-workout or between groups (p>0.05).

Conclusion Based on our findings in the current study, there seems to be no physiological benefit in performance 24-hours after wearing customized compression garments compared to a control condition. However, there seems to be a psychological benefit from wearing the garments with a reduced feeling of fatigue and an improved recovery

Fotboll är en intressant idrott att utforska ur skadeperspektiv då det är en av de mest skadedrabbade idrotterna. Fotbollsskador uppkommer antingen akut eller över tid och åtskiljs beroende om de inträffar under träning eller match. Tidigare studier av elitspelare visar att skador främst inträffar under match i form av akuta skador. De visar också att överbelastningsskador är mer träningsrelaterade och att flertalet av dem inträffar under försäsongen. Skadeincidensen beskrivs i antalet skador per 1000 tränings- respektive matchtimmar. Elitnivå har högre incidens än amatörnivå, framförallt under match. Sextio till nittio procent av alla skador drabbar nedre extremitet. Studier visar att de mest skadedrabbade kroppsdelarna är knän, lår och fotleder men även att ljumsk- och vadskador ofta förekommer.

Syftet med studien var att jämföra olika divisioner inom den manliga amatörfotbollen, för att se hur spelnivån kan inverka på skadebilden. Undersökningen avsåg säsongen 2009 och genomfördes i Halland med spelare från division två, tre och fyra involverade. En enkät användes för att samla in information om spelarnas skadehistorik. Totalt inkluderades 79 spelare i undersökningen och av dessa var 39 skadade och tillsammans hade de 49 skador. Vid beräkning av konfidensintervall för samtliga enkätsvar framkom inga signifikanta skillnader mellan divisionerna. Sextioen procent av skadorna var akuta och 39 % överbelastningsskador. De akuta skadorna var vanligast i division två och tre medan överbelastningsskador var vanligast i division fyra. Den totala skadeincidensen var 7,92 per 1000 matchtimmar och 2,92 per 1000 träningstimmar. Division tre hade högst skadeincidens för match med 10,63 skador och division fyra hade högst skadeincidens för träning med 4,09 skador. Av alla skador resulterade 30,6 % i en frånvaro mellan 1-7 dagar, 32,7 % mellan 8-28 dagar och 36,7 % mer än 28 dagar. Skadorna var främst lokaliserade till knä, lår och fot. Mittfältare var mest skadedrabbade följt av försvarare, anfallare och målvakter. I division två och fyra inträffade skadorna främst under för- och vårsäsongen medan det i division tre var vanligast med skador under höstsäsongen.

Decreased estrogen production is associated with changes in the skeletal, cardiovascular and muscular systems. At the level of skeletal muscles, it has been shown that a reduction in force production occurs at menopause but the underlying mechanisms are still unknown. The aim of the study was to investigate the effects of ovariectomy on myosin heavy chain (MyHC) composition. Additionally, we studied the effects of physical activity and the combined effects of physical activity and estrogen treatment on MyHC content in ovariectomised (OX) animals. Twenty-five rats were randomly assigned to five different groups: controls, runners, OX, ovariectomised runners and ovariectomised runners receiving estrogen. Exercise consisted of voluntary running for 5 weeks. Two muscles were analysed: m. extensor digitorum longus, EDL, (fast muscle) and m. soleus (slow muscle). MyHC content was analysed on 8% gel electrophoresis. The level of running activity is reduced in OX animals and estrogen administration is associated with the normalisation of the level of physical activity. Ovariectomy induces a shift from fast to slow MyHC isoforms in both the soleus and EDL. When OX animals are allowed to run, alterations in MyHC isoforms are still observed in the EDL but not in the soleus. When physical activity is combined with estrogen treatment no alterations are observed in both muscles. In conclusion, this study shows that ovariectomy induces alterations in the contractile properties of skeletal muscles and that physical activity in combination with estrogen treatment are associated with the maintenance of slow and fast muscle characteristics.

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.

Aims: Simultaneous measurement of right (RV) and left ventricle (LV) myocardial blood flow (MBF), oxygen extraction fraction (OEF), and oxygen consumption (MVO2) non-invasively in humans would provide new possibilities to understand cardiac physiology and different patho-physiological states. Methods: We developed and tested an optimized novel method to measure MBF, OEF, and MVO2 simultaneously both in the RV and LV free wall (FW) using positron emission tomography in healthy young men at rest and during supine bicycle exercise. Results: Resting MBF was not significantly different between the three myocardial regions. Exercise increased MBF in the LVFW and septum, but MBF was lower in the RV compared to septum and LVFW during exercise. Resting OEF was similar between the three different myocardial regions (similar to 70%) and increased in response to exercise similarly in all regions. MVO2 increased approximately two to three times from rest to exercise in all myocardial regions, but was significantly lower in the RV during exercise as compared to septum LVFW. Conclusion: MBF, OEF, and MVO2 can be assessed simultaneously in the RV and LV myocardia at rest and during exercise. Although there are no major differences in the MBF and OEF between LV and RV myocardial regions in the resting myocardium, MVO2 per gram of myocardium appears to be lower the RV in the exercising healthy human heart due to lower mean blood flow. The presented method may provide valuable insights for the assessment of MBF, OEF and MVO2 in hearts in different pathophysiological states.

Purpose: Rac1 and its downstream target PAK1 are novel regulators of insulin and exercise-induced glucose uptake in skeletal muscle. However, it is not yet understood how different training intensities affect the expression of these proteins. Therefore, we studied the effects of high-intensity interval training (HIIT) and moderate-intensity continuous training (MICT) on Rac1 and PAK1 expression in fast-type (gastrocnemius, GC) and slow-type (soleus, SOL) muscles in rats after HIIT and MICT swimming exercises.

Methods: The mRNA expression was determined using qPCR and protein expression levels with reverse-phase protein microarray (RPPA).

Results: HIIT significantly decreased Rac1 mRNA expression in GC compared to MICT (p = 0.003) and to the control group (CON) (p = 0.001). At the protein level Rac1 was increased in GC in both training groups, but only the difference between HIIT and CON was significant (p = 0.02). HIIT caused significant decrease of PAK1 mRNA expression in GC compared to MICT (p = 0.007) and to CON (p = 0.001). At the protein level, HIIT increased PAK1 expression in GC compared to MICT and CON (by ∼17%), but the difference was not statistically significant (p = 0.3, p = 0.2, respectively). There were no significant differences in the Rac1 or PAK1 expression in SOL between the groups.

Conclusion: Our results indicate that HIIT, but not MICT, decreases Rac1 and PAK1 mRNA expression and increases the protein expression of especially Rac1 but only in fast-type muscle. These exercise training findings may reveal new therapeutic targets to treat patients with metabolic diseases.

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. 

INTRODUCTION: Military tasks place considerable physiological demands on the soldier. It is therefore important to know the energy expenditure of soldiers while solving tasks in different environments. The purpose of this study was to describe the cardiorespiratory demands of certain movements and activities on ground combat soldiers during military field operations using body sensors and simulated combat.

MATERIALS AND METHODS: Movement characteristics and cardiorespiratory responses were assessed in 42 soldiers (three women) in the Swedish Army. The different posts assessed were commander, combat engineer, driver, and gunner. The military field exercises examined were urban operations and retrograde operations in rough terrain. Measurements included (1) body mass, (2) heart rate (HR) including maximal (HR_max), (3) velocity, (4) accelerations/decelerations, and (5) distance moved. Maximal aerobic capacity (V̇O_2peak, mL·kg^-1·min^-1) was tested in a laboratory setting when wearing combat gear and body armor.

RESULTS: There was a weak positive correlation (r = 0.41 and 0.28, both P < .05) between VO_2peak and percentage of time over 40% and 50% of maximal aerobic capacity during simulated combat. No differences were found for the different posts in time spent over 40% or 50% of maximal aerobic capacity and 76% of their HR_max (P > .05). Wearing combat gear and additional load while solving tasks resulted in mean HR varying between 98 and 111 beats·min^-1, corresponding with 50-57% of the soldiers HR_max. Studying all exercises, mean HR was 105 ± 11 beats min^-1, 54 ± 5% of HRmax corresponding to light work intensity. Soldiers performed between 2.8 and 4.9 accelerations/min in the different exercises. A significant correlation between V̇O_2peak (mL kg^-1 min^-1) and acceleration and m/min were found, implying that soldiers with good aerobic capacity were able to cope better with tasks requiring quick movements.

CONCLUSION: Conducting military operations in urban terrain and retrograde operations in rough terrain strains ground combat soldiers' cardiorespiratory system, with work intensities close to 40% of maximal aerobic capacity in 15-33% of mission time. Tasks with external load carriage include change of direction, accelerations, bounds, and jumping over obstacles, and physical fitness tests should replicate this. Findings in this study also add objective data to the physiological demands of work performed by combat soldiers while conducting urban operations and retrograde operations in rough terrain. These findings could be used to develop a model for classifying work demands for ground combat forces. © The Association of Military Surgeons of the United States 2022.

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.

We examined the influence of graded cold-water immersion (CWI) on global and regional quadriceps muscle perfusion with positron emission tomography (PET) and [15O]H2O. In 30 healthy men [33 ± 8 yr; 81 ± 10 kg; 184 ± 5 cm; percentage body fat: 13 ± 5%; peak oxygen uptake (VO2peak): 47 ± 8 mL·kg-1·min-1] quadriceps perfusion, thigh and calf cutaneous vascular conductance (CVC), intestinal, muscle, and local skin temperatures, thermal comfort, mean arterial pressure, and heart rate were assessed before and after 10 min of CWI at 8°C, 15°C, or 22°C. Global quadriceps perfusion did not change beyond a clinically relevant threshold (0.75 mL·100 g·min-1) in any condition and was similar between conditions {range of differences [95% confidence interval (CI)]: 0.1 mL·100 g·min-1 (-0.9 to 1.2 mL·100 g·min-1) to 0.9 mL·100 g·min-1 (-0.2 to 1.9 mL·100 g·min-1)}. Muscle perfusion was greater in vastus intermedius (VI) compared with vastus lateralis (VL) (2.2 mL·100 g·min-1; 95% CI 1.5 to 3.0 mL·100 g·min-1) and rectus femoris (RF) (2.2 mL·100 g·min-1; 1.4 to 2.9 mL·100 g·min-1). A clinically relevant increase in VI muscle perfusion after immersion at 8°C and a decrease in RF muscle perfusion at 15°C were observed. A clinically relevant increase in perfusion was observed in VI in 8°C compared with 22°C water (2.3 mL·100 g·min-1; 1.1 to 3.5 mL·100 g·min-1). There were no clinically relevant between-condition differences in thigh CVC. Our findings suggest that CWI (8-22°C) does not reduce global quadriceps muscle perfusion to a clinically relevant extent; however, colder water increases (8°C) deep muscle perfusion and reduces (15°C) superficial muscle (RF) perfusion in the quadriceps muscle. NEW & NOTEWORTHY Using positron emission tomography, we report for the first time muscle perfusion heterogeneity in the quadriceps femoris in response to different degrees of cold-water immersion (CWI). Noxious CWI temperatures (8°C) increase perfusion in the deep quadriceps muscle, whereas superficial quadriceps muscle perfusion is reduced in cooler (15°C) water. Therefore, these data have important implications for the selection of CWI approaches used in the treatment of soft tissue injury, while also increasing our understanding of the potential mechanisms underpinning CWI. Copyright © 2020 the American Physiological Society.

Bakgrund: I många idrotter såsom innebandy används vanligen statisk stretching (SS) som en del av uppvärmningen i tron om att öka prestation trots att statisk stretching har visat sig ha negativ inverkan på aktiviteter som involverar styrka, power, sprint och agility.

Syfte: Syftet med föreliggande studie var att undersöka om olika stretchmetoder SS, dynamisk stretching (DS) och ingen stretching (IS) som en del av uppvärmningen påverkade agility och/eller rörelseomfång (ROM) i hamstring hos manliga innebandyspelare i superelitligan och om en eventuell effekt varade upp till 10 min in i testtillfället.

Metod: Vid tre testtillfällen testades de olika stretchmetoderna (SS, DS och IS) efter avslutad uppvärmning. Alla tre stretchmetoderna utfördes vid varje testtillfälle efter randomiserad ordning på tre olika grupper. Agility och rörlighet testades med T-test (s) och passive straight leg raise test (^o) vid 0 min, 5 min och 10 min efter avslutad stretching. Totalt 9 testpersoner slutförde studien.

Resultat: Vid både 0 min och 5 min efter avslutad stretching noterades bäst tid på T-test (s) efter DS (10,20 ± 0,98 samt 9,92 ± 0,49). Vid 10 min noterades bäst tid efter IS (9,68 ± 0,16). Ingen statistisk signifikant skillnad fanns mellan de olika stretchmetoderna och T-test vid varken 0 min (p = 0,93), 5 min (p = 0,90) eller 10 min (p = 0,29). Vid både 0 min och 5 min efter avslutad stretching gav SS det högsta medelvärdet (^o) för ROM (73,56 ± 5,79 samt 71,67 ± 7,12). Vid 10 min gav DS det högsta medelvärdet (73,44 ± 8,75). Ingen statistisk signifikant skillnad fanns heller mellan de olika stretchmetoderna och ROM vid varken 0 min (p = 0,92), 5 min (p = 0,94) eller 10 min (p = 0,71).

Slutsats: Resultaten i denna studie saknar statistisk signifikans men visar på en svag trend att SS skulle kunna försämra agility samtidigt som den ökar ROM i hamstring och att prestationsförsämringarna gradvis stagnerar. Emellertid gav både DS och IS likvärdiga eller bättre resultat på T-test i förhållande till SS och med det i åtanke rekommenderas för utförande av SS att förlägga den vid separata tillfällen eller i anslutning med avslutad aktivitet.

Sammanfattning

Effekten av styrketräning och energiunderskott på viktminskning hos nybörjarmotionärer.

Till dagens datum råder ingen strategi för hur fettförlusten kan maximeras och muskelförlusten minimeras (Katzeff et al, 1995). Lockwood (2008) visar att 50 % av individer som endast använder kostrestriktioner återfår sin ursprungliga vikt igen. Kraemer & Ratamess (2008) visar att regelbunden träning som involverar stora som små muskelgrupper i samma pass frigör mest anabola hormoner. Muskler offras av kroppen eftersom de tar energi och de kan ge energi via glukoneogenes för att ex. jaga byten. I dagens samhälle signalerar stressen ett konstant frigörande av kortisol vilket har en negativ påverkan på bl.a. muskler. Detta hormonpåslag har förstärkts i samband med energiunderskott.

Är det möjligt att öka styrka med energiunderskott hos nybörjarmotionärer om protein tillförs för optimal kompenseringseffekt efter träningspass?

 4 av 6 överviktiga nybörjarmotionärer genomgick 8 veckor lång träningsperiod med betoning på hypertrofi, energiunderskott och mattiming i denna pilotstudie. 1RM tester har utförts på benpress i maskin, bröstmaskin samt sittande rodd med smalt grepp. Vilopuls har även tagits manuellt på morgonen av varje deltagare vid två tillfällen, före och efter träningsperioden. Testledare har tagit kroppsmått över byst, midja, rumpa samt vardera låren som utvärdering från energiunderskottet. Energiunderskottet har uppskattats till 500 kcal mindre än bibehållandet av ursprunglig vikt.

Alla deltagare har ökat sina styrkeresultat och minskat alla kroppsmått. En person har någon extra centimeter kring låren, men kan tyda på hypertrofi. Inga signifikans test har utförts.

BMI har minskat på alla deltagare medan kcalvärde har ökat för varje deltagare enligt BIA våg.

Ett mål har varit att öka den basala metabolismen i vila via större muskler. Det är främst en ökad fettförbränning som är fördelaktigt för målgruppen, vilket kan uppnås genom en ökad muskelmassa och kolhydratrestriktioner. Trots att pilotstudien har behandlat fysiskt inaktiva nybörjarmotionärer har hypertrofi uppnåtts även efter 4 veckors teknikträning för ökat antal aktiva motorenheter. Inga konkreta slutsatser kan ringas in på en pilotstudie, men positiva resultat har framkommit.

Purpose: Whiplash associated disorders remain a major health problem in terms of impact on health care and on societal costs. Aetiology remains controversial including the old supposition that the cervical muscles do not play a significant role. This study examined the muscle activity from relevant muscles during rear-end impacts in an effort to gauge their influence on the aetiology of whiplash associated disorders.

Methods: Volunteers were subjected to a sub-injury level of rear impact. Surface electromyography (EMG) was used to record cervical muscle activity before, during and after impact. Muscle response time and EMG signal amplitude were analysed. Head, pelvis, and T1 acceleration data were recorded. Results: The activities of the cervical muscles were found to be significant. The sternocleidomastoideus, trapezius and erector spinae were activated on average 59 ms, 73 ms and 84 ms after the impact stimulus, respectively, prior to peak head acceleration (113 ms).

Conclusion: The cervical muscles reacted prior to peak head acceleration, thus in time to influence whiplash biomechanics and possibly injury mechanisms. It is recommended therefore, that muscular influences be incorporated into the development of the new rear-impact crash test dummy in order to make the dummy as biofidelic as possible. ©2019 Chinese Medical Association. Production and hosting by Elsevier B.V

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.

Every year, approximately 8% of women and 1.5% of men in Sweden are subjected to sexual crimes, a trend that has dramatically increased over the past decade. A deeper analysis shows that about 1.5% of the total annually experience sexual crimes involving coercion or exploitation of a defenseless position, which equates to approximately 157,500 individuals, the majority of whom are women.

Individuals subjected to assault and serious assault has remained steady over the past 10 years, at about 3% and 0.6%, respectively. In numbers, this corresponds to approximately 315,000 and 63,000 people, with the majority being men. All statistics pertain to individuals aged 16-84 years.

The commonality between these offenses is that they are physical, involve a perpetrator, and create both physical and psychological stress for the victim, leading to traumatic consequences.

The project group's objective has been to develop a concept that enables a person in an emergency situation to automatically summon help without user interaction. There is not always time or the opportunity to call for help when one is being attacked.

The result is Friend In Need, an application designed for commercial smartwatches. Friend In Need detects when your body reacts with the fight or flight response. When the alarm is activated, a notification is sent to preset emergency contacts with a location guide to the user and a live update of the user's health parameters. By activating multiple functions when the alarm starts, Friend In Need collects evidence that helps law enforcement secure convictions against perpetrators.

Vasoneuroactive substances were applied through intradermal microdialysis membranes and characterized as itch- or pain-inducing in psychophysical experiments. Histamine always provoked itching and rarely pain, capsaicin always pain but never itching. Prostaglandin E[2] (PGE[2]) led preferentially to moderate itching. Serotonin, acetylcholine, and bradykinin induced pain more often than itching. Subsequently the same substances were used in microneurography experiments to characterize the sensitivity profile of human cutaneous C-nociceptors. The responses of 89 mechanoresponsive (CMH, polymodal nociceptors), 52 mechanoinsensitive, histamine-negative (CMi[H][i][s][-]), and 24 mechanoinsensitive, histamine-positive (CMi[H][i][s][+]) units were compared. CMi[H][i][s][+] units were most responsive to histamine and to PGE[2] and less to serotonin, ACh, bradykinin, and capsaicin. CMH units (polymodal nociceptors) and CMi[H][i][s] units showed significantly weaker responses to histamine, PGE[2], and acetylcholine. Capsaicin and bradykinin responses were not significantly different in the two classes of mechano-insensitive units. We conclude that CMi[H][i][s][+]units are "selective," but not "specific" for pruritogenic substances and that the pruritic potency of a mediator increases with its ability to activate CMi[H][i][s][+] units but decreases with activation of CMH and CMi[H][i][s] units.

The aim of this study was to examine the associations of cardiometabolic health markers with device-measured sedentary behavior (SB) duration and different intensities of physical activity (PA) among overweight working-aged adults with low self-reported PA levels. This cross-sectional analysis included 144 subjects (42 men) with mean age of 57 (SD 6.5) years and mean BMI of 31.7 (SD 4) kg/m². SB and standing time, breaks in sedentary time, light PA (LPA) and moderate-to-vigorous PA (MVPA) were measured for 4 consecutive weeks (mean 25 days, SD 4) with hip-worn accelerometers. Fasting plasma glucose, insulin, HbA_1c, triglycerides and total cholesterol, HDL and LDL were measured from venous blood samples. HOMA-IR index was calculated as a surrogate of insulin resistance. The associations were examined using linear models. LPA, MVPA, and daily steps associated with better insulin sensitivity and favorable plasma lipid profile, when adjusted for age, sex and BMI, whereas greater proportion of SB associated with insulin resistance and unfavorable lipid profile. As all PA intensities associated with better cardiometabolic health, the total daily duration of PA may be more relevant than intensity in maintaining metabolic health in overweight adults, if the current guidelines for PA are not met.Trial Registration: ClinicalTrials.gov NCT03101228, registered 05/04/2017, https://clinicaltrials.gov/show/NCT03101228 .

Accelerometry is a commonly used method to determine physical activity in clinical studies, but the duration and timing of measurement have seldom been addressed. We aimed to evaluate possible changes in the measured outcomes and associations with insulin resistance during four weeks of accelerometry data collection. This study included 143 participants (median age of 59 (IQR9) years; mean BMI of 30.7 (SD4) kg/m²; 41 men). Sedentary and standing time, breaks in sedentary time, and different intensities of physical activity were measured with hip-worn accelerometers. Differences in the accelerometer-based results between weeks 1, 2, 3 and 4 were analyzed by mixed models, differences during winter and summer by two-way ANOVA, and the associations between insulin resistance and cumulative means of accelerometer results during weeks 1 to 4 by linear models. Mean accelerometry duration was 24 (SD3) days. Sedentary time decreased after three weeks of measurement. More physical activity was measured during summer compared to winter. The associations between insulin resistance and sedentary behavior and light physical activity were non-significant after the first week of measurement, but the associations turned significant in two to three weeks. If the purpose of data collection is to reveal associations between accelerometer-measured outcomes and tenuous health outcomes, such as insulin sensitivity, data collection for at least three weeks may be needed © 2021 by the author. Licensee MDPI, Basel, Switzerland.

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.

Background: Retirement is associated with an increase in self-reported daily sedentary time, but no longitudinal evidence exists on how objectively measured sedentary time changes during retirement transition. The aim of this study was to compare objectively measured daily and hourly sedentary time before and after retirement and examine whether these changes differ by gender and occupational status.

Methods: The study population consisted of 478 participants (mean age 63.2 years, standard deviation 1.7, 85% women) from the Finnish Retirement and Aging Study. Sedentary time was measured using a wrist-worn triaxial ActiGraph accelerometer before and after transition to retirement with 1 year interval. Preretirement occupational status was categorized as manual and non-manual.

Results: Daily sedentary time was 8 hours 10 minutes in women and 9 hours 49 minutes in men before retirement. Considering all measurement days before and after retirement, daily sedentary time increased in women by 29 minutes (95% confidence interval [CI]: 20 to 38). Especially women retiring from manual occupations showed marked increase in sedentary time (63 minutes, 95% CI: 50 to 77). When only non-working days before retirement were considered, increase in daily sedentary time among women was less marked (16 minutes, 95% CI: 7 to 25). Among men, daily sedentary time did not change in retirement transition (−7 minutes, 95% CI: −26 to 12).

Conclusions: Objectively measured sedentary time increases among women and remains at high level among men during the retirement transition. Attention should be paid to reduce daily sedentary time in retiring women and men.

Many everyday tasks and also many sports require good grip and forearm strength. Everything from carrying boxes and lifting a child to grab the arms and legs in various martial arts, or holding a tennis racket involving the hand and forearm muscles in various ways. It is therefore important to train these muscles to prevent injuries and congestion and to perform well in sport. A well known way to train functional strength in the hand and forearm muscles is weight training with thick handles. The purpose of this study was to investigate the differences in muscle activity in the upper arm and forearm muscles as well as the deltoids between two bars of different diameter (28mm and 57mm) in two different weight training exercises using electromyography (EMG). The weight training exercises consisted of a pulling exercise in the form of a bench row and a pressing exercise in the form of close-grip bench press. The study also examines whether there is a connection between hand strength and muscle activity, and if there is any connection between hand size and muscle activity. Results show that muscle activity between the thick bars remained unchanged in the close-grip bench press. In the bench row exercise, however, significant increases were seen in the forearm flexors and m. biceps brachii while lifting the thicker bar. The forearm extensors showed an indication of muscle activity increases while lifting the thicker bar. However, there was no connection between hand strength and muscle activity and no correlation between hand size and muscle activity. The conclusion is that the pulling exercise with the thicker bar results in higher muscle activity in comparison to a standard Olympic bar in several muscles involved, not just those directly affected by the thicker bar.

Background: Altitude training stimulates erythropoietin hormone (EPO) release and increases blood hemoglobin (Hb) mass, which may result in improved oxygen (O-2) transport capacity. It was hypothesized in the present study that periodic inhalation of carbon monoxide (CO) might elicit similar physiological adaptations compared to altitude training.

Methods: Twelve male college student athletes, who were well-trained soccer players, participated. They performed a 4-week treadmill-training program, five times a week. Participants were randomly assigned into an experimental group with inhaling CO (INCO) (1 mL/kg body weight for 2 min) in O-2 (4 L) before all training sessions and a control group without inhaling CO (NOCO). CO and EPO concentrations in venous blood were first measured acutely at the 1st, 2nd, 4th, 6th, and 8th hour after INCO, and total hemoglobin mass (tHb), running economy and VO(2)max were measured before and after the 4 weeks training intervention.

Results: HbCO% increased from 0.7 to 4.4% (P < 0.05) after 1 h of CO inhalation and EPO increased from 1.9 to 2.7 mIU/mL after 4 h post CO inhalation (P < 0.05) acutely before the intervention. After the training, the tHb and VO(2)max in the INCO group increased significantly by 3.7 and 2.7%, respectively, while no significant differences were observed in the NOCO condition. O-2 uptake at given submaximal speeds declined by approximately 4% in the INCO group.

Conclusion: Acutely, EPO increased sharply post CO inhalation, peaking at 4 h post inhalation. 4-weeks of training with CO inhalation before exercise sessions improved tHb and VO(2)max as well as running economy, suggesting that moderate CO inhalation could be a new method to improve the endurance performance in athletes. © 2019 Frontiers Media S.A. All Rights Reserved.

Introduction: A complex interaction between muscles, tendons, bones, joints and nerves are required for optimal function of the human hand. It is known that an individual’s grip strength is vital for performance of physical demanding tasks such as strength training with free weights. Strength training including 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 investigation was to examine the difference in performance in multiple repetitions in two strength training exercises using two different sizes on the bar, to look for correlations between grip strength of the subjects hand and the amount of repetitions executed with two different size of the bar and finally the correlation of hand size and the amount of repetitions executed with two different size of the bar.

Method: 15 strength training men (23,9 ± 4,1 years), underwent measurements of hand size, maximum grip strength, 1 repetition maximum (1RM), a 80 % of 1RM weight strength test with two different  bar sizes.

Results: The results from the present investigation indicates a 21,1 % reduction of 80 % of 1 RM weight performance in repetitions executed in the bench press with the thicker diameter of the bar and a 66,2 % reduction in repetitions executed with a 80 % of 1 RM weight in the lying bench row with the thicker diameter of the bar. The size of the hand or the maximum grip strength does not influences the performance in the 80 % of 1 RM strength test.

Conclusion: With support of the results from this present investigation the size of the bar diameter significant influences the performance in maximum repetitions executed in a set in strength training with free weights, in a rowing exercise the repetitions executed reduced with 66,2 % and in the bench press the reduction of executed repetitions were 21,1 % with the thicker diameter of the bar. The size of the hand do not influences the performance of maximal executed repetitions with the thicker bar diameter. Maximal grip strength has no influence of the performance according to the findings of this investigation.

Preventing declines in cerebral blood flow is important for maintaining optimal brain health with aging. We compared the effects of a morning bout of moderate-intensity exercise, with and without subsequent light-intensity walking breaks from sitting, on cerebral blood velocity over 8 h in older adults. In a randomized crossover trial, overweight/obese older adults (n = 12, 70 +/- 7 yr; 30.4 +/- 4.3 kg/m²), completed three acute conditions (6-day washout); SIT: prolonged sitting (8 h, control); EX + SIT: sitting (1 h), moderate-intensity walking (30 min), followed by uninterrupted sitting (6.5 h); and EX + BR: sitting (1 h), moderate-intensity walking (30 min), followed by sitting (6.5 h) interrupted with 3 min of light-intensity walking every 30 min. Bilateral middle cerebral artery velocities (MCAv) were determined using transcranial Doppler at 13 time points across the day. The temporal pattern and average MCAv over 8 h was determined. The pattern of MCAv over 8 h was a negative linear trend in SIT (P < 0.001), but a positive quadratic trend in EX + SIT (P < 0.001) and EX + BR (P < 0.01). Afternoon time points in SIT were lower than baseline within condition (P <= 0.001 for all). A morning dip in MCAv was observed in EX + SIT and EX + BR (P < 0.05 relative to baseline), but afternoon time points were not significantly lower than baseline. The average MCAv over 8 h was higher in EX + SIT than SIT (P = 0.007) or EX + BR (P = 0.024). Uninterrupted sitting should be avoided, and moderate-intensity exercise should be encouraged for the daily maintenance of cerebral blood flow in older adults. The clinical implications of maintaining adequate cerebral blood flow include the delivery of vital oxygen and nutrients to the brain.

NEW & NOTEWORTHY: This is the first study to measure the combined effects of an exercise bout with breaks in sitting on cerebral blood velocity in older adults. Using frequent recordings over an 8-h period, we have performed a novel analysis of the pattern of cerebral blood velocity, adjusting for concurrent measures of mean arterial pressure and other potential confounders in a linear mixed effects regression. 

Copyright © 2019 the American Physiological Society.