Effects of whole body vibration and vocal function exercises in women : phonatory function, perceived vocal condition, and cortisol level

Abstract

Whole body vibration (WBV), the transmission of movement from a mechanical vibration source through the body, was explored as an alternative to vocal function exercises (VFE) to improve vocal function. Forty-five females with healthy voices were randomly assigned to one intervention group: WBV, VFE, or a combined intervention (WBV + VFE). The WBV group phonated /a/ on a vibrating platform. The VFE group performed vocal function exercises. The WBV + VFE group performed vocal function exercises on a vibrating platform. The aim of the study was to investigate the effects of the programmes on phonatory function (maximum frequency range, minimum/maximum frequency, maximum intensity), perceived vocal condition, and salivary cortisol levels. The results showed the VFE group significantly increased their maximum frequency range with increases in the maximum frequency after intervention (p < .05), with the WBV group showing the same trend. There was no statistically significant change in vocal intensity or salivary cortisol. On the self-rating of vocal condition, the WBV group rated it easier to phonate in the low frequency range after intervention compared to the WBV + VFE group (p < .05). The study suggests that WBV may be worth further exploring, as WBV showed similar gains in phonatory function as the well-documented VFE.