International normative values for the weight-bearing lunge test across age and sex in 899 healthy adults.

BACKGROUND

Ankle dorsiflexion is essential for lower extremity function and limitations in this motion are associated with musculoskeletal injury and decreased performance during functional tasks. The distance-based weight-bearing lunge test (WBLT) is a reliable and valid clinical measure of ankle dorsiflexion, yet normative data across age and sex are lacking.

OBJECTIVES

To establish adult age- and sex-specific normative values for the distance-based WBLT.

DESIGN

Cross-sectional, multi-country observational study.

METHOD: A total of 899 adults from Canada, Spain, and Iran completed demographic and clinical measures including height, Foot Posture Index (FPI-6), supination resistance, and bilateral WBLT performance using a standardized knee-to-wall protocol. Participants were stratified into seven age groups and by sex. Between-limb differences were examined with paired t-tests. Associations between WBLT and height, FPI-6, and supination resistance were assessed using Pearson correlations. Age and sex effects were evaluated using two-way ANOVA with Bonferroni-adjusted comparisons. Percentile-based clinical categories were generated for each age-sex subgroup.

RESULTS/FINDINGS: No meaningful difference was observed between limbs (p = 0.172, d = 0.05). WBLT performance declined progressively with age (p < 0.001, η2 = 0.283), with greater reductions evident beginning in the 60-69 age group. Males demonstrated slightly greater dorsiflexion than females across age groups (p = 0.003, η2 = 0.010). Height, FPI-6, and supination resistance showed small, non-clinically meaningful associations with WBLT scores (R2 ≤ 0.09).

CONCLUSIONS

This study provides robust age- and sex-specific normative values for the distance-based WBLT, improving clinical interpretation of weight-bearing ankle dorsiflexion across the adult lifespan.