Scaling of Limb Coordination Patterns in Maximal Velocity Running

Phase relationships and stability are tools employed from Dynamic Systems Theory (DST) to study pathology, aging, mechanics, and skill acquisition in human movement. Few investigations into human performance have utilized DST and maximum velocity running has received near no attention. We aimed to fill the gap by examining how the degree and stability of limb coordination patterns scale with running velocity. Assuming sprinting presents as an issue of optimality, we expect limb patterns to become increasingly antiphase (approaching 180°) and stable (lower STDev) as maximum velocity increases. METHODS: Twenty subjects (ranging from an Olympic sprinter to recreationally acvitve students) sprinted 50m at maximum velocity and motion capture was used to record kinematics on a 10m interval from the 30-40m point. Center of mass and limb angular positions were computed using a 12-marker model. Relative phase relationships (CRP) between the thighs (T-T), shanks (S-S), and unilateral relationships between the thigh and shank (T-S) were calculated from the Hilbert transform of the segment angles. We used Pearson correlations (α = .001) to assess the relationship between limb coordination and velocity. RESULTS: R2 values demonstrate that, as relative velocity increased, the mean CRP pattern became increasingly antiphase in the T-T (0.643) and S-S patterns (0.630). This was not evident in T-S (Left: 0.345; Right: 0.423). There was a strong and persistent inverse relationship between variability and relative velocity for T-T (-0.788), S-S (-0.695), and T-S (Left: -0.683; Right: -0.785) patterns. CONCLUSION: These preliminary data support our hypothesis that limb coordination is increasingly stable and antiphase with greater max velocity