Relations of Asymmetry in the Thickness of the Latissimus Dorsi Muscles to Pelvic Lateral Tilt Angle and Respiratory Function during Forced Expiration in Healthy Young Adult Males

Abstract

Purpose] The purpose of this study was to investigate the presence of asymmetry in the thickness of the latissimus dorsi muscles (LD) and the relations of the asymmetry to pelvic lateral tilt angle and respiratory function during forced expiration. [Participants and Methods] The subjects were 20 healthy males. Measurement items were the thicknesses of the bilateral LDs, pelvic lateral tilt angle and respiratory function.[Results] During resting expiration, the right LD was significantly thicker than the left LD. There was a correlation between the lateral asymmetry of the thicknesses of the LD and %IC. During forced expiration, the thickness of the left LD increased. The asymmetry in the thickness of the LD correlated with the pelvic lateral tilt angle during forced expiration and with %PE max. [Conclusion] These results suggest that asymmetry in the thickness of the LD is involved in %IC, %PE max, and pelvic stabilization in the frontal plane.