Lateral abdominal muscle symmetry in collegiate single-sided rowers

Although side to side symmetry of lateral abdominal muscle thickness has been established in healthy individuals, it is unknown whether abdominal muscle symmetry exists in athletes with asymmetrical physiological demands, such as those of single-sided rowers. The purpose of this study was to examine the oarside versus the non-oarside lateral abdominal musculature thickness in collegiate single-sided rowers, as measured by ultrasound imaging (USI).

The study was a prospective, cross-sectional, observational design. Thirty collegiate crew team members (17 males, 13 females, age 19.8±1.2 years) characterized as single-sided rowers participated. Resting muscle thickness measurements of the transversus abdominis (TrA), internal oblique (IO), and external oblique (EO) muscles were obtained via USI. Comparisons of absolute and relative muscle thickness between oarside and non-oarside were performed using paired t-tests. Potential differences based on gender, rowing experience, and history of low back pain were investigated using mixed model analysis of variance.

There were no clinically significant differences in absolute or relative thickness of the TrA, IO or EO on the oarside versus the non-oarside. There were no significant side to side differences in the relative muscle thickness of the TrA, IO or EO based on gender, rowing experience, or history of low back pain.

In this sample of single-sided rowing athletes, no clinically significant side to side differences in lateral abdominal muscle thickness were observed. Despite the asymmetrical functional demands of single-sided rowers in this study, thickness of the lateral abdominal muscles was symmetric.

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