Influence Of Training Status On Timing Of Improvements In Jump Performance Throughout 10 Weeks Of Lower Body Power Training.

To examine if underlying differences in the neuromuscular characteristics of stronger versus weaker individuals impact the timing of improvements during a power training phase. Twenty-three men with previous resistance training experience were randomized into one of three groups based on their squat one repetition maximum to body weight ratio (1 RM:BM): stronger group (S, n = 7,1 RM:BM = 1.97), weaker group (W, n = 8,1 RM:BM = 1.32), or control group (C, n = 8,1 RM:BM = 1.37). The S and W groups completed 10 weeks of ballistic training while the control group maintained their normal level of activity. Training involved 2 sessions/week consisting of 7 sets of 6 maximal effort jump squats at 0% 1RM (i.e. body mass only) and 1 session/week consisting of 5 sets of 5 jump squats at 30% 1RM. One week prior to initiating training all subjects underwent a familiarization and testing session involving a squat 1 RM and a series of countermovement jumps (CMJ). Testing was conducted again after week 5 (mid-test) and week 10 (post-test). To examine the time course of adaptations, experimental subjects were assessed with a CMJ test prior to the first training session in weeks 2,3,4,7,8 and 9. Data was collected using a linear position transducer and a force plate sampling at 1000Hz and analyzed using previously validated protocols. S had significantly (p ≤0.05) greater power output in the CMJ than the weaker group at baseline, mid- and post-testing sessions (Table 1). The change in peak power output relative to body mass (PP) from baseline for S was significant (p ≤0.05) in weeks 3,4, mid-test, 7,8,9 and post-test (Table 1). For W, the change in PP from baseline became significant (p ≤0.05) in weeks 7,8,9 and post-test (Table 1). S displayed a non-significant but practically relevant decrease in 1 RM:BM (effect size = 0.91) after the 10 week power training program. No differences in any parameters were observed for C following the 10 week period. These findings suggest it takes less time for stronger individuals to show performance improvements in response to power training than weaker individuals. However, following approximately 4 weeks there were no additional increases in the magnitude of performance improvements for the stronger individuals. In contrast, the plateau in jump performance improvement occurred only at the end of the 10 week program for weaker individuals. It remains unclear whether the addition of strength maintenance sessions within this program would have resulted in further increases in PP beyond week 4 for the stronger individuals. Weaker individuals would benefit from power training more rapidly following an initial increase in strength. For the well trained athlete, power training cycles should last approximately 3-4 weeks in the absence of any strength training/maintenance sessions.Table 1. Change in peak power relative to body mass (PP) from baseline throughout 10 weeks of power training. †Significant (p ≤0.05) difference between groups. ∗Significant (p ≤0.05) change from baseline. [ABSTRACT FROM AUTHOR]