BIOMECHANICAL DIFFERENCES BETWEEN LOADED COUNTERMOVEMENT AND STATIC SQUAT JUMPS

Abstract

It was the aim of this study to assess differences between countermovement (CMJ) and static (SJ) unloaded and loaded squat jumps. Eight male national/international level athletes and badminton players performed a series of jumps on two Kistler force plates. Maximum vertical force (Fmax) and rate of force development (RFDmax), net impulse (Impnet) and vertical take-off velocity (VT-O) were calculated and compared using a Two-Way (Jump x Load) ANOVA with two repeated factors. Fmax increased significantly with load and displayed a significant interaction with jump type. RFDmax showed significant jump main and interaction effects. Impnet only changed significantly with load. These results may lend credence to the spinal reflex or elastic energy theory of enhanced CMJ performance.