Quantifying humeral retrotorsion in young swimmers and association with swim volume

Abstract

ObjectivesTo compare the humeral retrotorsion (HRT) among non-athletes, amateur swimmers and competitive swimmers and to analyze the relationship between HRT and swim volume in competitive swimmers. DesignCross-sectional. SettingLaboratory. ParticipantsNinety children and adolescents, both genders (30 non-athletes: 11.50 ± 1.94 years; 30 amateur swimmers: 11.56 ± 1.81 years; and 30 competitive swimmers: 12.63 ± 2.02 years). Main outcome measuresHRT measurement through the bicipital forearm angle (BFA), by palpation, using an inclinometer to obtain the angle. ResultsCompetitive swimmers showed lower BFA (higher HRT) compared to the amateurs (mean difference: 8.3°; p = 0.013; effect size: 0.82) and to the non-athletes (mean difference: 8.5°; p = 0.010; effect size: 0.80). A significant fair negative relationship (r = −0.37; p = 0.04) was found between BFA and volume of swim. ConclusionCompetitive young swimmers present increased HRT and a higher volume of swim is associated with a lower BFA (higher HRT) in these athletes. These results can help to improve the understanding of osseous adaptations in young swimmers.