A comparison of coordination and its variability in lower extremity segments during treadmill and overground running at different speeds

BACKGROUND: Recently, the use of treadmills for walking and running has increased due to lifestyle changes. However, biomechanical differences in coordination between running on a treadmill or overground have not been adequately addressed.

RESEARCH QUESTION: The purpose of this study was to compare coordination and its variability in lower limb segments during treadmill and overground running at different speeds.

METHODS: Twenty physically active university undergraduate students participated in this study. Each participant ran trials for both overground and treadmill running at slow and fast speeds. Three-dimensional kinematic data of the lower limb segments were captured. The continuous relative phase (CRP) was used to compute coordination and its variability (VCRP) for foot, shank, and thigh segments of the dominant side of the participants.

RESULTS: A vector analysis using statistical parametric mapping (SPM) revealed that there were statistically significant differences in the calculated CRPs for treadmill and overground running in the stance phase of running and for different running speeds in the late stance and swing phases. However, the VCRPs calculated for the two locations and speeds did not exhibit any statistically significant differences.

CONCLUSION: The findings of this study suggest differences in segment coupling between treadmill and overground running may affect lower extremity biomechanics. In addition, changes in the coupling patterns for different running speeds suggest that segment coordination is not stable in the range of training speeds used by runners. Finally, the lack of differences in the variability of segment couplings during treadmill and overground conditions at different speeds potentially demonstrates similar dynamic neuromuscular control and degrees of freedom at these different running locations and speeds.