Effect of Additional Load on Power Output during Drop Jump Training

Plyometrics can be an effective way of improving power performance in many sports. The purpose of this study was to examine the effects of additional loading on power during drop jump training. Forty-two untrained physical education students with plyometric training background participated in a six-week training 3 times a week. Subjects were randomized to one of three training groups: without (FREE) and with a weight vest (VEST; 5% body weight), and a control group (CON). Pretraining and post-training measures of concentric peak power (PP), force (F(PP)) and velocity (v(PP)) at peak power and, in addition, time between eccentric and concentric peak power (t(PPEC)) were analyzed in a countermovement jump (CMJ) and a drop jump (DJ) from a height of 0.3 m. The FREE and VEST groups considerably improved PP in CMJ (p < 0.05), but v(PP) significantly increased (p < 0.05) and t(PPEC) significantly decreased (p < 0.05) only in the FREE group. The enhancement of PP and v(PP) was only demonstrated by the FREE group in DJ. The FREE group significantly decreased (p < 0.05) and the VEST group significantly increased (p < 0.05) t(PPEC) in DJ. It can be concluded that using additional load during drop jump training does not produce superior gains in power output when compared to a traditional drop jump training program..