Ankle muscle strength, joint hypermobility, and foot posture in children aged 5-10 years: A cross-sectional study

During childhood, foot posture, joint hypermobility, and foot and ankle strength may influence lower limb function. However, there is limited evidence analysing these variables together in the paediatric population. The study aims to analyse how foot posture, joint hypermobility, ankle mobility, and foot-ankle strength are related in children aged 5 to 10 years. A cross-sectional study was conducted in 196 healthy children aged between 5 and 10 years. Foot posture was assessed using the Foot Posture Index (FPI), general joint hypermobility using the Beighton score, and lower-limb-specific hypermobility using the Lower Limb Assessment Score (LLAS) and the Foot and Ankle Flexibility Index (FAFI). Ankle dorsiflexion was measured with the Lunge test, and isometric ankle strength was assessed using hand-held dynamometry. Descriptive analyses, correlations, and between-group comparisons were performed. No associations were found between foot posture, ankle dorsiflexion range of motion, or generalized joint hypermobility (Beighton score) and ankle muscle strength. In contrast, region-specific lower-limb hypermobility (LLAS and FAFI) showed only weak associations with ankle muscle strength. After adjustment for age, sex, and BMI-for-age z-score, only a limited number of associations remained statistically significant, and the observed effect sizes were small.

In healthy children, ankle muscle strength was not associated with foot posture, ankle dorsiflexion range of motion, or generalized joint hypermobility. Region-specific lower-limb hypermobility showed only weak associations with ankle muscle strength, most of which were attenuated after adjustment for age, sex, and BMI-for-age z-score.

• Foot posture and joint hypermobility are common in childhood and may influence lower limb function. • Previous studies have analysed foot type, hypermobility or strength separately, with heterogenous findings.

• Lower limb specific hypermobility (LLAS), but not Beighton score, was associated with ankle strength. • Hypermobile children showed greater relative ankle strength (BMI-normalised), suggesting threshold effects of joint laxity.