Effect of Whole Body Vibration on Three Maximum Repetition Sets of Push-ups - Pilot Study

Abstract

Whole body vibration (WB V) training is being used as a new method for improving strength and power. Increases in torque and EMG activity have been shown as an acute effect of locally applied vibration in fatiguing isometric contractions. However, it is not known how different magnitudes of WBV will affect dynamic resistive strength in 3 successive maximum repetition sets. PURPOSE: To determine the acute effect of 2 different WBV loads on 3 sets of maximum repetitions (REPS) of push-ups (MPU). METHODS: Seven healthy resistance exercise trained males (28 ± 7 yrs; 76.1 ± 7.7 kg; 173 ± 6 cm) volunteered to participate in this study which consisted of 1 familiarization and 4 testing visits, separated by 1 to 5 days. Familiarization consisted of 1 set of MPU (toes as pivotal point, final position with 90° angle at elbows and shoulders) and 30 s of light-loaded push-ups (approx. 15 REPS with hands on the vibration platform - VP, knees on a step positioned in front of the VP with hips at approx. 90° angle) in each vibratory load: LOW (2-4 mm; 30 Hz) and HIGH (4–6 mm; 50 Hz). Position distances for both push-up exercises were registered and reproduced in all test visits. Testing visits consisted of 3 sets of self-paced MPU performed in a counter-balanced order under the following conditions: (1) HVib - MPU sets were preceded by 30 s of light-loaded push-ups with VP set at HIGH, followed by 30 s rest, and another 2-min rest after each MPU set; (2) LVib - similar to HVib, with VP set at LOW; (3) NVib - similar to HVib with VP turned off; (4) CON - with no light-loaded push-ups, subjects rested before and during 3 min between MPU sets. Predetermined range of motion for all exercises was visually controlled. RESULTS: One-way repeated measures ANOVA showed no differences (p = .393) in total number of REPS in 3 sets of MPU, calculated as percentage of CON (114.7 ± 22.9 REPS), among HVib (81.3 ± 12.1 %), LVib (80.7 ± 8.0 %) andNVib (76.3 ± 8.0 %). CONCLUSIONS: Both LOW and HIGH loads of WBV seem to reduce, although not statistically significant, the detrimental effects in performance observed in the NVib condition. The large in-between subjects variation may be related to different inter-individual responses to WBV, and to different relative loads characteristic of weight-bearing exercises. Further studies are needed to confirm this effect in resistive strength performance.