Background: Ageing affects human body with decreased muscle mass, decreased range of motion (ROM) and decreases flexibility in lower extremity. Previous research has found differences in the relationship between age and shod running kinematics such as decreased step length, decreased ROM in the knee and ankle, changes in knee angles and decreased muscle strength in plantar flexors with age. Barefoot running is a current subject in the training world and many people today converts to barefoot running. This study aims to evaluate if barefoot running kinematics in an older group of runners are different compared to a younger group.

Aim: The aim of this study was to determine whether there are any differences in lower extremity kinematics; foot strike pattern, step length, and angles in knee and ankle at foot strike, midstance and toe-off between two age groups running without shoes.

Method:!The method used were a 2D-video analysis with a cross-sectional study design. Twelve participants in the older group, mean age 26.6 years (48-58) and thirteen in the younger group, mean age 52.3 years (23-31) fulfilled the study. The participants ran five minutes barefoot on a treadmill whilst video recording in sagittal and lateral plane of motion. Foot strike pattern (heel/mid-forefoot strike), step length (meters) and angles (degrees) were analyzed in the Dartfish software. Independent t-tests, Mann Whitney u-tests and chi-square tests were used to study significant differences between the two groups. 

Results: No significant differences were seen in foot strike pattern (p=0.54), step length (p=0.90) or in the angles of the knee, though a slight trend of increased flexion for the older runners could be seen in the phase of toe-off (p=0.13). No significant difference was seen in the angles of the ankle in frontal and sagittal plane.

Conclusion: No significant differences were seen in foot strike pattern, step length or angles in knee and ankle between the older and the younger group while running barefoot for a short period of time. A slight trend of increased flexion at toe-off for the older runners in barefoot running has been observed. The results of the study could indicate that an older group of well-trained runners could keep their running style whilst running barefoot for a short period of time, but further research in the area is needed, with a broader age- range and extended running interval to make any further conclusions.