Side differences in upper quarter mobility/stability are not related to serve velocity in tennis players with different levels of training experience.

Abstract

Objective: Tennis is characterised by repetitive serves and strokes predominately performed with one arm. This can lead to differences in upper quarter mobility/stability between the stroke and non-stroke arm, which could even enlarge with increasing training experience and negatively affect serve velocity. Thus, we determined side differences (i.e., limb symmetry index) in upper quarter mobility/stability and their association with flat and slice serve velocity in advanced (ITN ≤ 4) female and male tennis players (N = 42, mean age = 23.9 ± 9.3 years) with different levels of training experience (< 2 years: n = 14, 2-5 years: n = 17, 6-8 years: n = 11).

Results: Y Balance Test-Upper Quarter (YBT-UQ) side difference (i.e., composite score) and performances (i.e., medial reach) were largest in players with the lowest level of training experience (i.e., < 2 years). Further, YBT-UQ performances (i.e., medial reach and composite score) but not side differences were significantly correlated with flat and slice serve velocity, particularly in less experienced players. Our results suggest that significant side differences in upper quarter mobility/stability occur in less experienced players (indicative of increased injury risk) but they are not related to tennis-specific performance (i.e., serve velocity).