Effects of 6 weeks of periodized squat training with or without whole-body vibration on short-term adaptations in jump performance within recreationally resistance trained men

Lamont, HS, Cramer, JT, Bemben, DA, Shehab, RL, Anderson, MA, Bemben, MG. Effects of 6 weeks of periodized squat training with or without whole-body vibration on short-term adaptations in jump performance within recreationally resistance trained men. J Strength Cond Res 22(6): 1882-1893, 2008-The purpose of this study was to examine the effects of a 6-week, periodized squat training program, with or without whole-body low-frequency vibration (WBLFV), on jump performance. Males ranged in age from 20 to 30 years and were randomized into groups that did squat training with (SQTV, n = 13) or without (SQT, n = 11) vibration, or a control group (CG, n = 6). Measures of jump height (cm), peak power (Pmax), Pmax per kilogram of body mass (Pmax/kg), and mean power were recorded during 30-cm depth jumps and 20-kg squat jumps at weeks 1 (pretraining), 3 (midtraining), and 7 (posttraining). No significant group differences were seen for 30-cm depth jump height between weeks 1 and 7 (p > 0.05). Trial three (W7) measures were greater than those for trial two (W3) and trial one (W1) (p < 0.05). Significant group differences were seen for 20-kg squat jump height, with SQTV > SQT between weeks 1 and 7 (p < 0.05). Significant trial differences were seen, with W7 > W3 > W1 (p < 0.05) as well as for 30-cm depth jump Pmax percent change (W7 > W3 and W1 p < 0.05)). A significant trial effect was seen for 20-kg squat jump Pmax (W7 > W1, p < 0.05) and 20-kg squat jump Pmax/kg percent change (W7 > W3 > W1, p < 0.05). The addition of vibration to SQTV seemed to facilitate Pmax and mean power adaptation for depth jumps and Pmax for squat jumps, although not significantly (p > 0.05). Stretch reflex potentiation and increased motor unit synchronization and firing rates may account for the trends seen. Baseline squat strength, resistance training experience, and amplitude, frequency, and duration of application of WBLFV seem to be important factors that need to be controlled for.