Inter-limb differences in upper quarter mobility/stability are not associated with performance in competitive swimmers.

Background: The Y Balance Test-Upper Quarter (YBT-UQ) is a cost-effective, well-established, closed kinetic chain test to assess inter-limb asymmetries in the upper quarter that could negatively affect swimming performance. Thus, the aim of the present study was to determine YBT-UQ performances and inter-limb differences as well as its association with swimming performance in athletes with diverging levels of expertise.

Methods: Forty female and male competitive swimmers (age range: 10-22 years) with different expertise levels (A-squad: = 9, B-squad: = 12, C-squad: = 19) were tested (reach distances for the YBT-UQ) and swimming performance was calculated using the ratio of individual to world best time.

Results: YBT-UQ performances (i.e., inferolateral reach direction for the dominant arm: = .027, = .12 and the non-dominant arm: = .031, = .17) but not YBT-UQ inter-limb differences significantly differed between groups and were largest in swimmers with the lowest expertise level (i.e., C-squad). Further, YBT-UQ performances (i.e., inferolateral reach direction [= -.68 to -.70, both < .05] and composite score [= -.65 to -.67, both < .05] for both arms and medial reach direction for the non-dominant arm [= -.64, < .05]) but not inter-limb differences were significantly and negatively correlated with swimming performance among B-squad swimmers.

Conclusions: Our results suggest that inter-limb differences in upper quarter mobility/stability are not influenced by the level of expertise and have no significant associations with swimming performance. However, greater reach distances were correlated with lower swimming performance for the B-squad swimmers indicating that a training-related increase in upper quarter mobility/stability could worsen swimming performance in those athletes.