THE EFFECT OF BACK SQUAT RESISTIVE LOADS ON THE BIOMECHANICAL PERFORMANCE OF DROP JUMPS IN MALE RUGBY PLAYERS

Abstract

This study examined the effect of three different resistive loads (65%, 80%, & 93% of 1 RM) for the back squat on the biomechanical performance of the drop jump (DJ) in male rugby players. Twelve elite level rugby players participated in the study. Drop jumps were done prior to and after the back squat lifting at the different loads. All jumps were performed on a specially constructed sledge and force plate apparatus. Time in the air (flight time) and leg spring stiffness were the dependent variables. The results indicated that lifting at all loads significantly (p < 0.01) reduced flight time but lifting the 93% load caused a significant improvement (p < 0.05) in leg spring stiffness. From a practical viewpoint, the results support the use of a heavy back squatting prior to performing a fast SSC activity, such as drop jumping.