Inter-limb asymmetries in swimming and their impact on performance: evidence from a scoping review

The objectives of the present review were to: (a) map the studies analyzing bilateral asymmetries in specific (in-water tests) and non-specific (dry-land tests) swimming contexts and (b) investigate the effects of inter-limb asymmetries on swimming performance. Searches were systematically conducted on four databases. Out 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 to 17.4%, with four 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 five reporting no meaningful associations with swimming performance. 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.

This is a non-final version of an article published in final form in: Knihs, Débora A.; Bishop, Chris; Zimmermann, Haiko B.; Dal Pupo, Juliano. Interlimb Asymmetries in Swimming and Their Impact on Performance: Evidence From a Scoping Review. Strength and Conditioning Journal 45(6):p 642-662, December 2023. | DOI: 10.1519/SSC.0000000000000769