Upper Extremity Asymmetries in Collegiate Tennis Players Compared to an Athletic Control of Runners

Previous research on limb asymmetries of athletes participating in dominant-sided sports lacks an athletic control group. This study aimed to determine the magnitude of upper limb asymmetries in dominant-sided athletes (tennis players) compared to nondominant-sided athletes (cross-country runners). Men and women university athletes (10 tennis, 11 cross-country) participated. Dual-energy x-ray absorptiometry (DXA) was used to measure bone mineral content (BMC), bone mineral density (BMD), and lean mass (LM) of the whole body, upper extremities, and forearms. Circumference measurements were taken at mid-biceps and widest part of the forearms. Bony breadth of the elbow was measured with sliding calipers placed at the medial and lateral epicondyles. Grip strength was assessed with a dynamometer. Mixed-model ANOVA was used to analyze data between dominant/nondominant sides and between sports. There were no significant differences in age (p = .150), height (p =.783) or body mass (p = .066) between teams. No differences were shown between sports for total body BMC (p = .544), total body BMD (p = .535), or total body LM (p = .843). Sport × side interaction was significant (p < .05) for lower arm circumference, elbow bony breadths, total upper extremity LM, total upper extremity BMC, total upper extremity BMD, forearm BMC, ultra-distal forearm BMC, mid-distal forearm BMC, one-third forearm BMC, and ultra-distal forearm BMD. Morphological differences between sports were localized to the arm. Sport specificity influences mass and volume (circumference, LM, BMC) of the limb, with BMD particularly enhanced in ultra-distal forearm.