Age- and sex-specific differences in muscle flexibility and joint laxity in junior competitive swimmers

Abstract

This study assessed age- and sex-specific differences in muscle flexibility and joint laxity in junior competitive swimmers. Of the 452 recruited swimmers aged 10-18 years, 256 were male and 196 were female.Muscle flexibility and joint laxity of the upper and lower extremities were measured using five and seven tests, re spectively. Two-way analysis of variance (age group and sex) was performed. When interaction effects or the main effect by age group was detected, post hoc comparisons were used to test differences between variables by the Tukey-Kramer method. The results showed no significant interaction effects between the tests. Heel Buttock Dis tance (HBD), predominantly reflecting muscle flexibility, and ankle dorsiflexion angle during knee extension indi cated decreased flexibility in older swimmers (p< 0.05). Knee extension angle reflecting joint laxity, indicated in creased laxity in older swimmers (p< 0.05). Shoulder and hip joint internal rotation angles reflecting muscle flexi bility and joint laxity, were decreased in older swimmers (p< 0.05), while toe floor distance (TFD) showed in creased mobility (p< 0.05). Sex differences were observed in shoulder rotation width, distance between middle fin gers, shoulder joint internal and external rotation angles, elbow joint extension angle, hip joint internal rotation an gle, straight leg raising angle, HBD, and TFD (p< 0.05).