An investigation into the effect of varying plyometric volume on reactive strength and leg stiffness in collegiate rugby players

Abstract

The purpose of this study was to identify the role that low and high volume plyometric loads have on the effectiveness of developing stretch shortening cycle capability in collegiate rugby players. The experiment was carried out utilising a between- group, repeated measures design. Thirty six participants (Age 20.3 ±1.6 yrs, mass 91.63 ±10.36kg, height 182.03 ±5.24cm) were randomly assigned to one of three groups, a control group (CG), a low volume plyometric group (LPG) and a high volume plyometric group (HPG). Data were collected from a force plate, and measures of reactive strength index (RSI) and leg stiffness were calculated from jump height, contact time and flight time data. Drop Jumps were used to gather data to measure RSI and double leg hops were used to gather leg stiffness data. The analysis demonstrated an overall significance in the interaction effect between group* time (F =4.01, p <0.05) for RSI. Bonferroni post hoc analysis indicated that both the LPG training group (p = 0.002) and HPG training group (p = 0.009) demonstrated a significance from the control group. No significant interaction effect between time*group or main effect were observed for leg stiffness (F = 1.39, p = .25). The current study has demonstrated that it is possible to improve reactive strength capabilities to a significant level via the use of a low volume plyometric programme. The low volume programme elicited the same performance improvement in RSI values as a high volume programme whilst undertaking only a quarter of the volume. This suggests that strength and conditioning coaches may be able to benefit from the ability to develop more time efficient and effective plyometric programmes