Sex-Specific Muscle Size in Climbers: A Novel Cross-Sectional Study of an Ultrasonographic Analysis of Abdominal Wall Muscles

Abstract

Aim: This study aimed to evaluate and compare the thickness of the external oblique (EO), internal oblique (IO), transversus abdominis (TrAb), rectus abdominis (RA), and the interrecti distance (IRD) between male and female climbers, using B-mode ultrasonography to identify potential sex-based morphological differences. Results: Significant sex-based differences were observed in the thickness of several abdominal wall muscles—specifically the right IO, right RA, left EO, left IO, and left RA. No significant differences were found in the remaining muscles. Overall, male climbers exhibited greater muscle thickness than females, except for the left EO, which was thicker in the female group. Regression analysis showed that sex was a relevant factor associated with RA thickness and contributed, to a lesser extent, to the variability observed in both IO and EO muscles. Conclusion: This study highlights sex-related differences in abdominal muscle thickness among trained climbers. While male participants generally showed greater muscle thickness, the left EO was thicker in females. These morphological differences may reflect sex-specific anatomical adaptations, but further research is needed to determine their functional relevance. Current and future findings may contribute to the development of sex-specific training, rehabilitation, and injury prevention strategies in climbing.