Effects of two plyometric training programmes of different intensity on vertical jump performance in high school athletes

Although plyometric training is a significant component of most conditioning programme designs, little research exists with regards to the design/structure of specific plyometric training interventions and the intensity involved. The aim of this study was to compare the effect of intensity manipulation on a 6-week plyometric training programmes on vertical jump performance. Eighteen healthy adolescent male subjects were randomly allocated to a periodised plyometric intensity (INCR), a constant moderate plyometric intensity (CONS) and a control (CONT) group, for a 6-week plyometric training programme. Pre- and post-training measurements of net impulse, vertical take-off velocity, jump height and peak force were calculated from a countermovement jump. Contact time and flight time, rebound height and reactive strength index were calculated from a drop jump. INCR and CONS groups achieved improved vertical jump performance compared to CONT (P<0.05). Although there were no significant differences (P>0.05) between CONS and INCR for any of the performance variables, there was a trend for greater improvement for the INCR group. In conclusion, manipulation of exercise intensity for short duration plyometric training could be less significant than the intervention itself. Longer training durations and density as well as consideration of specific plyometric exercises merit further investigation.