Asymmetries In NCAA Division I Tennis Players Compared To Control Group

Some limb asymmetries are an expected adaptation to years of training for athletes participating in dominant-sided sports. However, previous research on this topic lacks an athletic control group. PURPOSE: The aim of the study was to determine the magnitude of contralateral upper limb asymmetries in dominant-sided athletes (tennis players) compared to nondominant-sided athletes (cross-country runners). METHODS: NCAA Division I female athletes (7 tennis, 7 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 and forearms. Circumference measurements were taken at mid-biceps and the widest part of the forearms. Sliding calipers were used to measure bony breadth of the elbow. Grip strength was assessed with a dynamometer. Mixed-model ANOVA was used to analyze data between dominant/nondominant sides and between sports. RESULTS: The tennis players weighed more than the runners (p = .007), but there were no differences between the sports for age (p = .217), height (p = .662), total body LM (p = .282), total body BMC (p = .598), or total body BMD (p = .955). The sport x side interaction was significant for lower arm circumference (p < .001), forearm LM (p = .003), and forearm BMC (p = .026). The runners had 7.4% more LM in the dominant forearm compared to the nondominant side, but there was an asymmetry of 16.8% for the tennis players. The asymmetries for forearm circumference and forearm BMC were 5.0% and 8.1%, respectively, for tennis players but negligible (< 1%) for runners. The interaction for upper arm circumference, elbow breadth, forearm BMD, and grip strength were not significant (p > .05). CONCLUSION: In general, the differences between tennis players and cross-country runners were localized to the forearm. Sports specificity appears to influence mass and volume (circumference, LM, BMC) more than BMD.