Lower-limb joint hypermobility and associations with physical performance in school-aged children: a cross-sectional study.

Lower-limb joint hypermobility has been associated with alterations in physical function; however, its independent relationship with physical performance in asymptomatic school-aged children remains unclear. This study investigated the association between lower-limb joint hypermobility and physical performance and determined whether these associations persisted after adjustment for potential confounding variables. A cross-sectional study was conducted in 165 school-aged children aged 4-13 years. Lower-limb joint hypermobility was assessed using the Lower Limb Assessment Score (LLAS). Participants were classified as non-hypermobile (LLAS < 7; n = 120) or hypermobile (LLAS ≥ 7; n = 45). Physical performance was evaluated using the Youth Fitness International Test (YFIT) battery, including the 20-m sprint, handgrip strength, and standing long jump. Group comparisons were performed using the Mann-Whitney U test, and multivariable linear regression analyses adjusted for age, sex, BMI-for-age standard deviation score (BMI-SDS), and weekly sports participation frequency were conducted. In the unadjusted analyses, children with lower-limb joint hypermobility demonstrated significantly slower 20-m sprint times (median [IQR]: 5.40 [4.90-6.10] vs. 5.00 [4.48-5.47] s; p = 0.005; r = 0.22), lower handgrip strength (9.80 [6.65-14.40] vs. 13.70 [10.40-16.75] kg; p < 0.001; r = 0.28), and shorter standing long jump distances (1.19 [1.00-1.32] vs. 1.30 [1.15-1.46] m; p = 0.002; r = 0.24). However, lower-limb joint hypermobility was not independently associated with any physical performance outcome after adjustment for age, sex, BMI-SDS, and weekly sports participation frequency (20-m sprint: p = 0.861; handgrip strength: p = 0.868; standing long jump: p = 0.389).

conclusionLower-limb joint hypermobility was associated with poorer physical performance in unadjusted analyses but was not an independent determinant of physical performance after accounting for demographic, anthropometric, and lifestyle factors. Longitudinal studies are needed to clarify these associations throughout childhood. WHAT IS KNOWN: • Joint hypermobility is common in children and may be associated with musculoskeletal symptoms and functional limitations. •Previous studies have reported inconsistent findings regarding the relationship between joint hypermobility and physical activity levels. WHAT IS NEW: • Children with lower-limb joint hypermobility demonstrated poorer physical performance in unadjusted analyses. •After adjustment for age, sex, BMI SDS and sports participation frequency, lower-limb joint hypermobility was not independently associated with physical performance. •Demographic and lifestyle factors explained a substantial proportion of the variability in physical performance.