Interlimb Asymmetries in Swimming and Their Impact on Performance: Evidence From a Scoping Review

ABSTRACT The objectives of this review were to (a) map the studies analyzing bilateral asymmetries in specific (in-water tests) and nonspecific (dry-land tests) swimming contexts and (b) investigate the effects of interlimb asymmetries on swimming performance. Searches were systematically conducted on 4 databases. Of 768 studies examined, 60 were eligible for the final selection (https://osf.io/46gya). Twenty-eight studies analyzed asymmetries during in-water tests, with asymmetry values ranging from 2.7 to 60.0%, and most studies ( n = 18) reported significant between-limb differences ( p < 0.05). Asymmetries were also analyzed during dry-land tests in 24 studies, with asymmetry values ranging from 1.1 to 16.6%. Interestingly, most of these studies ( n = 12) did not verify any significant between-limb differences ( p > 0.05). Eight studies measured asymmetries in both contexts and reported asymmetry values from −24.1–17.4%, with 4 studies finding significant differences between body sides ( p < 0.05). Seven of the 60 studies selected investigated the relationship between asymmetries and swimming performance, with 5 reporting no meaningful associations. In conclusion, significant asymmetries in swimming are more evident during in-water than during dry-land tests. In addition, the few studies investigating asymmetries' influence on swimming performance reported that asymmetries rarely impact swimming performance.