The purpose of this study was to quantify the effect of plyometric training (PT) in changes of jump abilities and ankle joint motions on repeated-rebound-jumps exercise without buffer function of lower limb joints. Seven female collegiate runners executed 10-repeated rebound jumps training (10 RJ) on a switch mat with maximum effort. Each subject executed the training program twice a week for 5 consecutive weeks. Parameters of repeated-rebound jumps training involved jump height (m), the contact time (s), flight time (s), and rebound jumps index (=RJ-index). Three-dimensional ankle joint kinematics of each subject were captured using ten motion capture systems (250 Hz). As a result, RJ-index, jump height, and flight time were increased significantly between pre-and post-test (p<0.001). But, the contact time decreased significantly. The relationships between rebound jumps index and jump height and between rebound jumps index and the durations of contact phase were highly correlated (r=0.858, r=-0.739; p<0.001). In addition, the time (%) between start and finish phase in the dorsiflexion angle of ankle joint was reduced significantly between pre-and post-test (p<0.001). The repeated-rebound-jumps exercise was shown to have an effect on improvement in stretch-shortening cycle (SSC) performance of lower limb joints in distance runners. The RJ-index and the time between start and finish phase in the dorsiflexion angle of ankle joint was shown to be a valid evaluation index of SSC performance. Therefore, repeated-rebound-jumps exercise is a significant training protocol where ankle behavior improves and where the performance of stretch-shortening cycle is enhanced.
Animals ; Ankle ; Ankle Joint ; Biomechanics ; Female ; Humans ; Joints ; Lower Extremity ; Plyometric Exercise

PURPOSE: This study is to investigate influence of tDCS on lower limb muscle activity and balance ability in soccer player. METHODS: Sessions were conducted with 15 subjects in tDCS group and 15 in action observation training group for 20 minutes, 5 sessions a week, for 8 weeks. All soccer players underwent 30 minutes of plyometric training before main exercise. To evaluate lower limb muscle activation, rectus femoris and biceps femoris were taken measure using surface electromyogram system and to evaluate balance ability, surface area, whole path length, limited of stability were measured using biorescue. RESULTS: Regarding balance shown in surface area, whole path length, limited of stability and muscle activation in rectus femoris and biceps femoris, tDCS group showed more significant change than action bservation training group. CONCLUSION: Therefore, intervention using tDCS is more effective in improving lower limb muscle activation and balance ability than action observation training.
Lower Extremity* ; Plyometric Exercise ; Quadriceps Muscle ; Soccer* ; Transcranial Direct Current Stimulation*