The effectiveness of whole-body vibration in preventing vocal fatigue

Abstract

Vocal fatigue is a common concern. Most people have experienced it after intensive vocal use (Solomon, 2008). Individuals with complaints about vocal fatigue usually report a sense of increased speaking effort, discomfort and/or tension in the neck, limited voice use, and other symptoms (Hunter et al., 2020; Welham & Maclagan, 2003).

Researchers have been studying methods to relieve vocal fatigue, such as straw phonation exercises, vocal function exercises, and resonant voice therapy (Imaezue, 2017; Kang et al., 2020; Zadeh et al., 2024). Besides conventional voice exercises, with documented positive effectiveness in improving neuromuscular performance, increasing blood circulation and metabolism, and relieving muscle fatigue and pain, vibrational therapy has aroused researchers’ attention in voice therapy (Alentorn-Geli et al., 2008; Cardinale & Wakeling, 2005; Cochrane & Stannard, 2005; Ritzmann et al., 2014; Tihanyi et al., 2007). In the study by Yiu et al. (2021) and Yiu and Lee (2023), 10-minute machine-generated whole-body vibration has revealed positive effectiveness in relieving vocal fatigue, as demonstrated by the significantly increased highest pitch production and reduced subjective self-rating scores.

There have been few studies on the prevention of vocal fatigue compared to the treatment. However, prevention can protect individuals from unnecessary pain and loss induced by vocal fatigue. Given the positive effectiveness of whole-body vibration, the present study aimed to investigate whether a 10-minute whole-body vibration can be used as an effective method to prevent vocal fatigue.

Thirty-eight vocally healthy adults were recruited in the present study. Participants were randomly assigned to the experiment or control groups to receive either a 10-minute whole-body vibration or vocal resting as a vocal preparation task. After that, participants were asked to perform a vocal loading task to induce vocal fatigue. Outcomes involving scores of the self-perceived level of vocal effort, the highest fundamental frequency production, estimated subglottal air pressure, and the thyrohyoid distances were measured at the pre-prevention phase (the baseline level before vocal preparation tasks), post-prevention phase (immediately after whole-body vibration or vocal resting), and post-reading phase (after vocal loading tasks). The duration of vocal loading tasks in the two groups was also counted.

Results of the present study revealed that the duration of vocal loading tasks in the experimental group was significantly longer than that in the control group. Results also supported that a 10-minute whole-body vibration can be used to prevent vocal fatigue, as demonstrated by no significant decrease or less significant decrease in thyrohyoid distances after vocal loading tasks compared with the control group.

This study was the first attempt to evaluate the effectiveness of whole-body vibration in preventing vocal fatigue and to assess physiological laryngeal muscle changes following vocal fatigue using ultrasound. It provided empirical evidence to support the use of a 10-minute whole-body vibration as a vocal warm-up exercise to relax laryngeal muscle tension before vocally demanding tasks. The results of the present study would benefit the populations susceptible to vocal fatigue, especially those seeking an effective method to prevent it.

Keywords: vocal fatigue, whole-body vibration, laryngeal ultrasound. (495 words)