The purpose of this study was to determine the effects of two drop jump (DJ) training
methods on the strength qualities of the leg extensors and vertical jumping performance.
Thirty-five males were allocated to either a control group or one of two training
groups, required to perform 72 - 90 DJ per week for 6 weeks: DJ for maximum rebound
height (DJ-H) or DJ for maximum height and minimum ground contact time (DJ-H/t). The
subjects were tested before and after the training on leg extensor function for maximum
strength and speed-strength under concentric and stretch-shortening cycle muscular
actions, and on vertical jumps from a standing position and) a run-up. ANOVA with
repeated measures showed that a 20 % gain in reactive strength (RS) for the DJ-H/t
group was significantly greater (p < 0.05) than the other groups, however, this did
not transfer to vertical jumping performance. The DJ-H group did not achieve a significant
training effect. It was concluded that DJ-H/t method was effective for the development
of RS, but training with DJ-H was not intense and/or specific enough to stimulate
gains in strength qualities of the leg extensors or jumping performance.
Key words
Plyometrics - muscular power - training - reactive strength
