The Effects of Platform Vibration On Upper Body Muscle Activity During Pushups

Abstract

Whole body vibration (WBV) platform training studies have reported increases in lower body skeletal muscle electromyography (EMG) activity during both static and dynamic squatting postures, but little if any effect on upper body skeletal muscle activity. In contrast to this, studies using vibrating cables or vibrating dumbbells have reported an improvement in upper body muscular performance. These data suggest that proximity to the vibrating stimulus was critical to the activation of selected muscle groups. PURPOSE: To investigate the effects of vibration stimulus from a WBV platform on the upper body EMG muscle activity of recreationally trained males during the pushup exercise. METHODS: To determine changes in muscle activity during dynamic pushups, EMG data was recorded from the pectoralis major (PM), latissimus dorsi (LD), triceps brachii (TB), & biceps brachii (BB) with results expressed as a % of maximum voluntary exertion (MVE). Subjects (n=15) performed pushups at no vibration (NV) or 6 random pairings of frequency (25, 35 & 45 Hz) and amplitude (2 or 4 mm). Ratings of perceived exertion (RPE) were determined using the Borg RPE scale following each condition. RESULTS: With NV, ANOVA of the PM (45.8 ± 3.4%MVE) and TB (42.5 ± 3.4%MVE) showed significantly greater activity (p<.05) than the LD (12.0 ± 3.4%MVE) and BB (7.0 ± 3.4%MVE). There were no statistically significant increases in EMG muscle activity of the PM or LD at any vibration setting over the NV condition. However, the pairing of 45Hz and 4mm resulted in statistically significant increases (p<.05) in the EMG muscle activity of the TB (4.37 ± 1.48 %MVE), and BB (7.64 ± 2.5%MVE) over the NV condition. RPE data confirmed that subjects perceived the WBV stimulus to be statistically more intense than NV. CONCLUSIONS: Our data indicate that performing pushups on a WBV platform is similar to squatting on a WBV platform with the proximal muscles responding significantly to vibration set at 45Hz and 4mm. However, the data also indicate that the pushup position limited the transmissibility of the vibration stimulus to the muscles furthest away from the platform. Though RPE data indicate a perceived increase in effort during vibration training, an effective posture to increase the transfer of the vibration stimulus to the distal muscles in the upper body core remains unknown.