Static plantar biomechanics and foot postural adaptations to long-term classical ballet training in collegiate female dancers: a cross-sectional comparative study

Long-term classical ballet training imposes repetitive mechanical demands on the foot–ankle complex, progressively restructuring its morphology and biomechanical function. While dynamic plantar loading has been well characterized, static weight-bearing adaptations arising from prolonged training remain poorly defined. This study evaluated the foot arch index (FAI), plantar pressure distribution (PPD), bilateral static weight-bearing distribution (BSWD), hallux valgus angle (HVA), and rearfoot postural alignment in collegiate ballet dancers relative to non-dancer controls. This cross-sectional study recruited 120 healthy female collegiate participants (60 ballet dancers and 60 non-dancer controls), matched by age and academic level, with body mass index (BMI) recorded as a descriptive covariate rather than used as an active matching variable. Static plantar pressure parameters and the FAI were quantified using the JC Mat optical plantar pressure analyzer, while rearfoot postural angles were derived from standardized posterior-view digital photographs analyzed with Biomech 2019 software. Intergroup comparisons were conducted using independent-samples t -tests and Mann-Whitney U test. The ballet group showed significantly lower bilateral FAI values (left: 0.14 ± 0.05; right: 0.15 ± 0.04) than controls (left: 0.23 ± 0.05; right: 0.24 ± 0.04; p < 0.01). Six-subregional PPD analysis revealed significantly elevated loading at the medial metatarsal and medial heel, with reciprocally reduced loading at the lateral longitudinal arch and lateral heel in dancers ( p < 0.01). Analysis of five composite regions further confirmed greater forefoot and medial loading and lower lateral loading in dancers ( p < 0.01), with no significant differences in the midfoot and rearfoot. BSWD symmetry was preserved in both groups. Although rearfoot angles fell within the neutral alignment range and HVA values were classified within Valgus Class I in both groups, the ballet group exhibited significantly greater values on the left foot for both parameters ( p < 0.05). Collegiate ballet dancers exhibit a biomechanically distinctive static foot profile, characterized by high-arched morphology, forefoot-dominant and medially redistributed plantar loading, preserved BSWD symmetry, and a subtle left-lateralized valgus tendency in rearfoot and hallux alignment, collectively reflecting the musculoskeletal characteristics observed in relation to prolonged classical dance training. These findings provide a quantitative framework to inform dance-specific footwear design, orthotic prescription, and evidence-based injury-prevention protocols for collegiate dancer populations.