2019 Volume 3 Issue 1 Pages 21-25
The purpose of this research is to understand the effects that changes in body position have on muscular activity of accessory muscles during vocalization．
Subjects were 14 healthy adults with no medical history of respiratory, musculoskeletal, or vocal organ issues．
Measurements were made at three positions: supine, seated, and standing. Sound pressure level during maximum vocalization and muscular activity of rectus abdominis and abdominal external oblique muscles were measured．
A trend was observed for greater sound pressure level at maximum vocalization when standing compared to when seated （p=0.056）. No significant difference in rectus abdominis muscle activity was observed between the body positions. Significantly higher muscle activity for abdominal external oblique muscles when supine compared to when seated was observed （p<0.05）.
This research suggests that muscular activity of the accessory muscles of respiration during maximum vocalization changes due to differences in body position. This is expected to be of use for deciding on body position when practicing vocalization．
