Abstract
Jump distance per step in bounding exercises from the standing position increases
with increasing number of steps. We examined the hypothesis that the joint kinetic
variables of the stance leg would also increase accordingly. Eleven male athletes
(sprinters and jumpers) performed bounding exercise, starting from the double-leg
standing posture, and covered the longest distance possible by performing a series
of seven forward alternating single-leg jumps. Kinematic and kinetic data were calculated
using the data by a motion capture system and force platforms. Hip extension joint
work were decreased at third step (1st: 1.07±0.22, 3rd: 0.45±0.15, 5th: 0.47±0.14 J•kg−1; partial η2: 0.86), and hip abduction joint power were increased (1st: 7.53±3.29, 3rd: 13.50±4.44, 5th: 21.37±9.93 W•kg−1; partial η2: 0.58); the knee extension joint power were increased until the third step (1st: 14.43±4.94, 3rd: 17.13±3.59, 5th: 14.28±2.86 W•kg−1; partial η2: 0.29), and ankle plantar flexion joint power increased (1st: 34.14±5.33, 3rd: 37.46±4.45, 5th: 40.11±5.66 W•kg−1; partial η2: 0.53). These results contrast with our hypothesis, and indicate that increasing
the jump distance during bounding exercises is not necessarily accompanied by increases
in joint kinetics of stance leg. Moreover, changes in joint kinetics vary at different
joints and anatomical axes.
Key words
plyometric training - single-leg - horizontal direction - 3-dimensional motion analysis
