Effects Of Six-weeks Of Weight-lifting And Plyometric Exercises On Muscle Mass And Vertical Jump Performance

Abstract

PURPOSE To determine the effect of 6 six weeks of weight-lifting training combined with plyometric exercises on vertical jump performance and maximal strength. METHODS Thirty-four physical educations students (24.2 ± 0.4 yr, mean ± SEM) were randomly assigned to the training group (TG, n = 15) or non-training control group (CG, n = 19). TG subjects trained 3 times per week during 6 weeks by weight lifting and plyometric exercises. During a countermovement vertical jump (CMJ) height jumped (VJH), rate force development (RFD), mechanical positive impulse (MPI), peak power (PP), mean power (MP), maximal force (MF) were assessed with a force plate. Similarly, 1 RM of incline leg press (ILP), leg extension (LE) and half squat (HS) were calculated. Leg lean mass (LLM) was assessed by DXA. Differences were established using the corresponding statistical Student's t tests (p<0.05). The influence of lean mass changes on performance was assessed using bivariate correlation analysis. RESULTS Significant differences were found in all CMJ related variables except in MF in the TG compared to the CG (table 1). In addition, the TG increased significantly the 1 RM in every exercise and LLM with training (table 1). Furthermore, LLM increased by a third more in TG than in GC (p<0.05). No correlation was found between LLM development and the enhancement of either 1RM performance or CMJ-related variables.Table 1: Changes in 1 RM and CMJ in the training and the control groups (mean ± SEM). *P <0.05 between groups; $P <0.05 intragroup difference before and after training.CONCLUSION 6-weeks strength training combined with plyometric exercises enhances leg muscle mass and improves both, maximal dynamic force (1 RM) and countermovement performance in physical education students. Granted by Gobierno de Canarias Gobierno de Canarias (PI2000/067) and Ministerio de Educación, Cultura y Deportes (AP2000-3652).