Comparison of Foot Structure, Function, Plantar Pressure and Balance Ability According to the Body Mass Index of Young Adults

OBJECTIVES: This study compared foot arch height, plantar fascia thickness, a range of motion assessments of the ankle joint, strength of the ankle joint, plantar pressure, and balance between obese and normal weight young adults. METHODS: Fifty-two participants were required for the present study design to achieve 80% power, 0.8 effect size (η2), and an alpha level of 0.05. The participants were categorized to normal weight or obese groups based on BMI (≤ 24 kg/m(2) and ≥ 25 kg/m(2), respectively). The foot and ankle disability index and Sport survey were completed by the participants before the measurements. Foot arch height was measured using the navicular drop test, and plantar fascia thickness was measured using ultrasound. Plantar pressure and balance tests were also conducted, followed by ankle joint range of motion and strength tests. RESULTS: Foot arch height and plantar fascia thickness was significantly higher in the obese group compared with the normal weight group (p < 0.01). There were significant differences in eversion of ankle strength, plantar pressure in the big toe and heel and anterior-posterior balance between normal and obese weight groups (p < 0.05). CONCLUSION: Obese young adults had more abnormalities in the medial longitudinal arch, plantar fascia, and plantar pressure as well as weakened ankle eversion strength and balance problems compared with the normal weight group.