The effect of vertical whole-body vibration on lower limb muscle activation in elderly adults: Influence of vibration frequency, amplitude and exercise. (June 2016)

• Record Type: Journal Article
• Authors: Lam, Freddy M.H.; Liao, L.R.; Kwok, Timothy C.Y.; Pang, Marco Y.C.
• Is Part Of: Maturitas. Volume 88(2016)
• Page Start: 59
• Page End: 64
• Publication Date: 2016-06
• Subjects: Older adults -- Whole body vibration -- Muscle activity; Climacteric -- Periodicals; Menopause -- Periodicals; Climacteric -- Periodicals; Geriatrics -- Periodicals; Menopause -- Periodicals; Middle Aged -- Periodicals; Climatère -- Périodiques; Ménopause -- Périodiques; Climacterium; Climacteric; Menopause; Electronic journals; Periodicals; 612.66
• DOI: 10.1016/j.maturitas.2016.03.011
• Languages: English
• ISSNs: 0378-5122

Abstract

Highlights: Whole-body vibration increased the activity of major leg muscle groups in elderly adults. The muscle activity induced is greatest in erect standing and single-leg standing. Low-intensity whole-body vibration activates leg muscles as effectively as high-intensity whole-body vibration. Low-intensity whole-body vibration may be a useful adjunct intervention for frail elderly adults. Abstract: Objective: This study aimed to investigate how whole-body vibration (WBV) and exercise and their interactions influenced leg muscle activity in elderly adults. Study design: An experimental study with repeated measures design that involved a group of ambulatory, community-dwelling elderly adults (n = 30; 23 women; mean age = 61.4 ± 5.3 years). Main outcome measures: Muscle activity of the vastus lateralis (VL), biceps femoris (BF), tibialis anterior (TA), and gastrocnemius (GS) was measured by surface electromyography (EMG), while participants were performing seven different exercises during 4 WBV conditions (condition 1: frequency = 30 Hz, amplitude = 0.6 mm, intensity = 2.25 units of Earth's gravity ( g ); condition 2: 30 Hz, 0.9 mm, 3.40 g ; condition 3: 40 Hz, 0.6 mm, 3.65 g ; condition 4: 40 Hz, 0.9 mm, 5.50 g ) and a no-WBV condition in a single experimental session. Results: Significantly greater muscle activity was recorded in VL (3%–148%), BF (16%–202%), and GS (19% –164%) when WBV was added to the exercises, compared with the same exercises without WBV (p ≤ 0.015). The effect of vibration intensity on EMG amplitude was exercise-dependent in VL (p = 0.002), and this effect was marginally significant in GS (p = 0.052). The EMG activity induced by the four WBV intensities was largely similar, and was the most pronounced during static erect standing and static single-leg standing. Conclusions: The EMG amplitude of majority of leg muscles tested was significantly greater during WBV exposure compared with the no-WBV condition. Low-intensity WBV can induce muscle activity as effectively as higher-intensity protocols, and may be the preferred choice for frail elderly adults.