AUTHOR=Borgmann Katharina , Panzer Stefan , Limpach Sam , Muehlbauer Thomas 

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

JOURNAL=Frontiers in Sports and Active Living

VOLUME=6

YEAR=2024

URL=https://www.frontiersin.org/journals/sports-and-active-living/articles/10.3389/fspor.2024.1382779

DOI=10.3389/fspor.2024.1382779

ISSN=2624-9367

ABSTRACT=<sec><title>Background</title><p>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.</p></sec><sec><title>Methods</title><p>Forty female and male competitive swimmers (age range: 10–22 years) with different expertise levels (A-squad: <italic>n </italic>= 9, B-squad: <italic>n </italic>= 12, C-squad: <italic>n </italic>= 19) were tested (reach distances for the YBT–UQ) and swimming performance was calculated using the ratio of individual to world best time.</p></sec><sec><title>Results</title><p>YBT–UQ performances (i.e., inferolateral reach direction for the dominant arm: <italic>p </italic>= .027, <italic>η<sub>p</sub></italic><sup>2 </sup>= .12 and the non-dominant arm: <italic>p </italic>= .031, <italic>η<sub>p</sub></italic><sup>2 </sup>= .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 [<italic>r </italic>= −.68 to −.70, both <italic>p </italic>&lt; .05] and composite score [<italic>r </italic>= −.65 to −.67, both <italic>p </italic>&lt; .05] for both arms and medial reach direction for the non-dominant arm [<italic>r </italic>= −.64, <italic>p </italic>&lt; .05]) but not inter-limb differences were significantly and negatively correlated with swimming performance among B-squad swimmers.</p></sec><sec><title>Conclusions</title><p>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.</p></sec>