Bilateral Comparison of Passive Shoulder Horizontal Adduction Range of Motion in Elite Tennis Players.

Background: Elite level tennis players subject their dominant extremity to high levels of repetitive eccentric deceleration as the shoulder undergoes extensive internal rotation and cross arm adduction, placing large demands on posterior shoulder structures. While the associated loss of dominant (D) arm internal rotation range of motion (ROM) relative to the non-dominant (ND) arm has been extensively studied and quantified among overhead athletes, horizontal adduction (HADD) loss has been far less explored in current literature. The purpose of this study was to objectively measure passive D and ND HADD ROM and examine differences in D-ND HADD ROM in elite tennis players. The authors hypothesized that significantly lower D shoulder HADD ROM compared to the ND upper extremity would be observed in both male and female elite tennis players at all ages. Study Design: Cross-sectional observational study. Methods: A total of 317 uninjured, elite-level tennis players were assessed for differences between D-ND HADD passive ROM using a digital inclinometer. Subjects volunteered to participate and were currently training and competing. Subjects were divided into two groups by age (12 to 17, and 18 and over). Subjects were positioned supine while a single physiotherapist stabilized the ipsilateral scapula and performed all measurements without applied overpressure. A descriptive analysis was performed, with paired-samples t-tests examining D-ND differences within each group and independent-samples t-tests comparing the deficit between age groups. Results: There were (178 males and 139 females) measured in this investigation. Significantly less D arm HADD was measured compared to the ND arm in male (7.58±6.97°) (p<0.001) and female players (3.80±6.01°) (p<.0001). Additionally, the D-ND deficit was significantly larger in 18-30-year-old male players (8.2°) than in junior males (4.7°) (p = 0.005), whereas the deficit in female players was not statistically different across age groups (p = 0.71). Conclusion: The results of this descriptive study demonstrate a significant decrease in D arm HADD ROM in elite tennis players compared to the ND arm. Larger differences were measured in older male players, likely associated with the increased number of years played with this population. Decreased HADD likely represents the chronic adaptations that develop in the posterior shoulder structures with extensive repetitions required for skill development and training. Level of Evidence: 3.