Acute effect of heavy pre-loading on horizontal and vertical jump performance
Date
2000
Authors
Scott, Stefan Lewis
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Abstract
The purpose of this study was to investigate the acute effect of neural activation via heavy dynamic pre-load, consisting of one set of five repetition maximum (5RM) back squats (to a 90° knee angle), on countermovement vertical jump (VJ) and horizontal standing long jump (HJ) performance. Furthermore, the effects of pre-loading on these two plyometric exercises were examined for learning effects over the course of four separate testing sessions. 19 physically active males (age = 25.0 ± 4.8 yrs; weight= 79.3 ± 6.6 kg) experienced with back squats participated in the study. Each subject took part in eight exercise sessions: four practice and four testing sessions. The four practice sessions were designed to allow learning effects for VJ and HJ to stabilize and to determine 5RM back squat. One practice session consisted of a 10 min standardized warm-up (5 min cycling, 5 min stretching), two sets of VJ and HJ (each VJ and HJ set consisted of four jump repetitions) with a 5 min rest between sets (RBS), progressive 5RM back squat testing, and two final sets of VJ and HJ (5 min RBS). Mean SRM value improved significantly over the four practice sessions (164.2 ± 25.1 kg vs. 196.9 ± 23.0 kg). The four testing sessions each consisted of a standardized warm-up, one set of four VJ and four HJ jumps, a 5 min rest, 5RM back squat, a 5 min rest, and the final set of VJ and HJ jumps. Pre- and post-SRM VJ and HJ order was randomly assigned and counter balanced. Results indicated that no significant differences occurred between mean or maximal VJ and HJ sets performed 5 min prior to and 5 min after SRM back squat for the final practice session (control) or any of the four testing sessions. No linear improvement across time was observed over the course of the five sessions for mean or maximal pre- and post-SRM VJ and HJ performance. Thus, heavy dynamic loading with a SRM back squat performed between sets of VJ and HJ jumps did not significantly change mean or maximal height or distance jumped in an individual session. Additionally, no progressive learning effects or changes in performance occurred from repeated exposure to the heavy pre-loading neural activation protocol.