Effect of Vocalization on Static Handgrip Force Output


Rodolico, C., Oberholzer, R., Smith, S. Drexel University, Health Science Department, Philadelphia, PA

Purpose: This study examined differences in maximal static handgrip force between three conditions: passive breathing, forced exhalation, and vocalized exhalation. We hypothesized that handgrip force would be greater during vocalized exhalation compared to passive breathing and forced exhalation. Methods: Eighteen women and 12 men (24.9+ 5.9 years) performed maximal-effort, two-second static handgrip exercise during a passive breathing, forced exhalation, and vocalized exhalation condition. Three trials were conducted, each with a different condition order. There were twenty-second rest intervals between each condition and ninety-second intervals between each trial. A handgrip dynamometer and chest ventilation strap were used to measure force (N) and relative chest expansion during trials (AD Instruments, Powerlab 26T). A two-way repeated measures ANOVA was used to determine differences across conditions and trials with a 0.05 significance level (mean + SD). Results: The average handgrip force during vocalization (251.2 + 76.0 N) was greater than both passive breathing (201.2 + 118.4 N; pConclusion: Vocalized exhalation increased average static handgrip force by 25% compared to passive breathing and by 11% compared to forced exhalation. We hypothesize that vocalization increases sympathetic drive which may enhance overall motor unit activation increasing muscle force production. Further study investigating the effect of vocalization on muscle potentiation and sympathetic drive is suggested.

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