Purpose: The aim of this study was to determine the effects of lower rib cage lateral expansion limitation on the maximal inspiratory and expiratory pressures and on abdominal muscle activity during maximal respiratory breathing in healthy subjects. Methods: Fifteen healthy male subjects voluntarily participated in this cross-sectional study. During maximal breathing, maximal inspiratory and expiratory pressures were measured, and abdominal muscle activity was determined with using surface

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... romyography. Also, the measurement was repeated with using a non-elastic belt to the lower rib cage for limiting of lateral expansion. A Wilcoxon signed-rank test was performed for obtaining the statistical difference with a significance level of 0.05. Results: The findings of this study are as follows: 1) There were no significant differences in maximal inspiratory and expiratory pressure with and without lower rib cage lateral expansion (p> 0.05), 2) There was no significant difference in abdominal muscle activity during the maximal inspiratory phase (p> 0.05). However, right external oblique muscle activity decreased significantly during maximum exhalation with lower rib expansion limitation (p< 0.05). Conclusion: The results of the current study indicate that a non-elastic belt was effective in decreasing right external oblique muscle activity during forced expiratory breathing in healthy subjects. Key Words: Abdominal muscle activity, Maximal inspiratory and expiratory pressure, Respiratory pressure meter recruitment was required due to the abnormally high position of the diaphragm. 12 Perri and Halford 12 reported a correlation between chronic musculoskeletal pain and abnormal breathing. Abnormal breathing pat-This is an Open Access article distribute under the terms of the Creative Commons Attribution Non-commercial License (https:// creativecommons.org/license/by-nc/4.0.) which permits unrestricted non-commercial use, distribution,and reproduction in any medium, provided the original work is properly cited.