Abstract
The influence of counter movement speed on vertical force, power, take-off velocity and EMG activity in vertical jump was investigated. Three male subjects performed counter movement jump (CMJ) and static jump (SJ) on a force platform. Stretching speed of the femoral muscles was controlled by changing the counter movement speed (y_-) of CMJ. Vertical force, knee angle, ankle angle and EMG of M. vastus lateralis were simultaneously recorded. The take-off phase was divided into two phases; i.e., the descending phase (-) and ascending phase (+) of the center of gravity. The counter movement speed shows significant correlation with take- off velocity (y(t_3)), EMG activity of the descending phase (mEMG_), the averaged force (f_+), and the averaged power (P_+), of the ascending phase. These results indicate that the counter movement speed influences the jumping performance in vertical jump.
