Effects of Different Magnitudes of Whole-Body Vibration on Dynamic Squatting Performance

Abstract

The purpose of this study was to examine the effects (a) of different whole-body vibration (WBV) accelerations when applied simultaneously during a set of squats on performance and perceived exertion and (b) of different linear increases and decreases of vibrations during the squats. It is a randomized, crossover experimental design. Undergraduate students (3 female; 16 male) participated. Each participant completed 5 laboratory sessions in this study (4 familiarization and 1 test session). The test session then had each participant complete one 20-second set of dynamics quarter-squats for 5 separate conditions followed by 5 minutes of rest. Squatting was performed at maximum speed from full extension knee with plantar-flexion ankle to a knee angle of 70° (0° = anatomic position) with dorsiflexion ankle. All sets were performed on the WBV platform in random order, where the 5 different conditions were (a) no WBV-sham, (b) 30 Hz (30 Hz low amplitude), (c) 50 Hz (50 Hz high amplitude), (d) 30-50 Hz (increasing frequency from 30 to 50 Hz; 1 Hz per second with high amplitude), and (e) 50-30 Hz (decreasing frequency from 50 to 30 Hz; 1 Hz per second). There was a significant decrease in the mean velocity of squatting performed during the 30- to 50-Hz condition compared with all other conditions (p ≤ 0.05). There were a significantly lower amount of repetitions performed during the 30- to 50-Hz exposure compared with the no-WBV and 30-Hz conditions. There was a significantly lower Rating of Perceived Exertion (RPE) during the 30-Hz condition compared with the no-WBV, 50-Hz, 30-50-Hz, and 50-30-Hz conditions.