Fig. 1.
Thigh angular position versus time for two representative subjects, with dashed regions of the graph indicating the ground contact phase. (A,C) Male recreationally trained athlete at sub-maximal and maximal speeds. (B,D) Male sprinter at sub-maximal and maximal speeds. Faster running speeds were achieved with higher frequencies and greater total amplitudes of thigh angular motion, resulting in greater thigh angular velocities. At top speed, the slope of the angular position versus time curve during ground contact was steeper for the sprinter (D) than for the recreationally trained athlete (C), indicating a greater absolute value of the average angular velocity of the stance thigh during ground contact (ωc). Per Eqn 6, greater ωc was a direct determinant of the faster top running speed attained by the sprinter.