2018 Volume 2 Issue 1 Pages 15-19
【Introduction】Changes in body position affect the accessory muscles of respiration that are active during vocalization. The purpose of this research is to understand the effects that changes in body position have on the muscular activity of accessory muscles of respiration during vocalization in healthy adults.
【Subjects】The subjects were ７ healthy adult males with no medical history of respiratory, musculoskeletal, or vocal organ issues.
【Methods】Measurements were taken in three positions: supine, seated, and standing. The length of the longest continuous vocalization, and the lengths and starting times of the muscular activity of the rectus abdominis and abdominal external oblique muscles during vocalization were measured.
【Results】The longest continuous vocalization was significantly longer for the sitting and standing positions compared to the supine position （p<0.01）. The rectus abdominis muscular activity was higher for standing compared to sitting （p<0.05） positions. In regard to muscle activity starting times for rectus abdominis and abdominal external oblique muscles, starting times were significantly earlier for the sitting and standing positions compared to the supine position （p<0.05）（p<0.01）.
【Observations / Conclusion】The muscle activity of the accessory muscles of respiration during vocalization differs depending on the body position. This is expected to be of use in deciding on body position when practicing vocalization.
