Activation of trunk muscles during end-inspiration of abdominal breathing: Comparison among four different positions

Abstract

[Purpose] The purpose of this study was to compare the activation of trunk muscles during end-inspiration of abdominal breathing among four different back exercise positions to investigate potential effects on the activation of trunk muscles. [Subjects] Sixty healthy male adults volunteered to participate in the study. [Methods] Each subject was instructed regarding abdominal breathing and the study procedure. While the maximal voluntary contraction and endinspiration of abdominal breathing of individual muscles were being performed, the activity of the muscles was measured using surface electromyography. The activity of the muscles while performing end-inspiration of abdominal breathing was normalized to the percentage of maximal voluntary contraction (% MVC). [Results] Right and left erector spinae and external oblique showed significant differences among the positions between before and after endinspiration of abdominal breathing(EIAB). The prone-on-elbows position demonstrated the greatest increase post-EIAB. [Conclusion] End-inspiration of abdominal breathing appears to be effective in the four different positions for activating the erector spinae and external oblique trunk muscles, but not rectus abdominis.