The effects of whole-body vibration on upper- and lower-body EMG during static and dynamic contractions

Abstract

Whole-body vibration (WBV) training uses a vertically oscillating platform and reports suggest that this perturbation elicits reflexive muscle contractions that augment muscle activity and contribute to increased strength. No WBV study has measured both upper- and lower-body muscle activation. The purpose of this study was to determine the optimal WBV stimulus (frequency x amplitude) to increase electromyography (EMG) in upper- and lower-body muscles for three distinctive unloaded actions: isometric semi-squat, dynamic leg squats, and static and dynamic bilateral bicep curls. Surface EMG was measured for the vastus lateralis (VL), biceps femoris (BF), biceps brachii (BB), and triceps brachii (TB) in 10 recreationally active male university students (24.4+/-2.0 years; mean+/-SD) when WBV was administered at 2 and 4 mm and at 25, 30, 35, 40, and 45 Hz. EMG changes are reported as the difference between WBV and no WBV EMG root mean square expressed as a percentage of maximum voluntary exertion (%MVE). In static semi-squat, WBV increased muscle activity 2.9%-6.7% in the VL and 0.8%-1.2% in the BF. During dynamic squatting, WBV increased muscle activity in the VL by 3.7%-8.7% and in the BF by 0.4%-2.0%. In a static biceps curl, WBV had no effect on BB EMG, but did increase TB activity 0.3%-0.7%. During dynamic biceps curls, WBV increased BB EMG activity by 0.6%-0.8% and TB activity by 0.2%-1.0%. The higher WBV amplitude (4 mm) and frequencies (35, 40, 45 Hz) resulted in the greatest increases in EMG activity.

Effects of whole-body vibration on blood flow and neuromuscular activity in spinal cord injury

“…Furthermore, in healthy subjects, greater EMG activity with high-frequency WBV training (40 and 45 Hz) has been reported when compared with lower frequencies (25 and 30 Hz). 8 In our study, the lack of differences in the EMG activity between frequencies could be due to the reduced EMG response of SCI patients in respect to healthy subjects, 21 as well as to the marked difference in the EMG patterns among SCI subjects; 21 therefore, this lack of statistical significance could be due to a type II error.…”

“…6 Therefore, part of the rehabilitation of SCI patients should focus on the activation of muscular and vascular systems. 4 The application of whole-body vibration (WBV) with platforms has been shown to improve muscular 7,8 and vascular [9][10][11] functions. These effects are strongly dependent on the type of platform, protocols and vibration parameters (that is, frequency).…”

“…These effects are strongly dependent on the type of platform, protocols and vibration parameters (that is, frequency). 7 Specifically, greater vibration frequencies induce higher-muscle activity 8 and greater blood flow 11 than lower frequencies. Moreover, the most common protocol used to apply WBV consists of short bouts (30-90 s) with B60 s rest between the sets.…”

Effect of Bone Tissue on Vibration-Induced Electrical Activity of Muscles

“…Vib ra ti ons in the 30-100 Hz fre qu ency range we re re por ted to pro vi de mo re in cre a se in musc le elec trom yog rap hic (EMG) ac ti vity. 10,19,23 The fre qu ency of vib ra ti on was 46 Hz in the study.…”

“…[9][10][11][12][13] Pre vi o us stu di es have shown that vib ra ti on in cre a ses musc le elec tromyog ra hic (EMG) ac ti vity. [14][15][16][17][18][19][20][21][22] But, it has not be en re por ted whet her bo ne has an ef fect on the in crea se in musc le EMG ac ti vity ca u sed by vib ra ti on or not. The aim of this study was to de ter mi ne whether ra di us bo ne ex po sed to cyclic mec ha ni cal lo ading af fects musc le elec tri cal ac ti vity of m. fle xor car pi ra di a lis in he althy adult vo lun te ers.…”