C-27 Free Communication/Poster- Strength Testing and Training: MAY 31, 2007 7:30 AM 12:30 PM ROOM: Hall E
PURPOSE: The purpose of this study was to examine the chronic and acute effects of a 6 wk, periodized Squat training program, with (G2) or without (G3) low frequency vibration upon select force/velocity characteristics during isometric and dynamic tasks. A secondary purpose was to assess both total body, and regional changes in body composition.
METHODS: Participants (G1 n = 6; G2 n = 13; G3 n = 11; ranged in age from 18 to 30 years) were randomized into either a 6 wk periodized Squat training regimen, with or without whole body low frequency vibration or a control group. Measures of dynamic and isometric strength (1RM Squats and Isometric Quarter Squats), dynamic power (Depth Jumps and Squat jumps with a 20 Kg load) and body composition (DXA) were assessed. Subjects where also exposed to an acute vibration stimulus pre training (week 0), mid training (week 3), and post training (week7) to monitor possible adaptations resulting in an increased responsiveness to acute vibration exposure.
RESULTS: Both training groups increased significantly for the Squat 1RM (Kg) from baseline to week 7 compared to the controls. There were significant group differences for Rate of Force Development at 250 ms, initial peak in force (N), and Peak RFD (N/S). There were also significant group differences for Force at 250ms (N), Force at initial peak (N), and MVC (N). There were significant differences in Peak jump power (W) between G2 and G3 from weeks 1 to 3 under both jumping conditions. Both training groups had significant increases in total lean tissue (g), lean trunk tissue (g), and lean leg tissue (g), and significant decreases in percent leg fat (%)(Statistical significance was set at p < 0.05).
CONCLUSIONS: The addition of whole body vibration to a 6 week, periodized resistance training protocol did not significantly improve 1RM measures for the Smith Machine Squat beyond resistance training alone. The vibration frequency and amplitude used appeared to be too intense for most subjects as post activation depression rather than post activation potentiation was seen during jump tests following vibration.No significant chronic adaptation was seen. Trends were seen favouring the addition of vibration to resistance training with regards to increased peak isometric rates of force development. Vibration positively impacted increases in lean leg tissue.