Kinematic Characteristics of Lower Limb Muscle Activity and Isokinetic Strength During Fundamental Ballet Movements in Dancers with Chronic Ankle Instability

Purpose: This study aimed to investigate the characteristics of lower extremity muscle activity, isokinetic strength, range of motion, and balance in ballet dancers with chronic ankle instability (CAI) to provide fundamental data for injury prevention and rehabilitation strategies.Methods: Female ballet dancers were divided into the CAI (n = 20) and control (n = 10) groups.EMG analysis evaluated muscle activity in the tibialis anterior, peroneus longus, and gastrocnemius during four ballet movements: arabesque relev, pass relev, first position relev, and first position jump.Isokinetic ankle strength was measured at three angular velocities (60/sec, 120/sec, and 180/sec) for inversion, eversion, plantar flexion, and dorsiflexion movements.The ankle range of motion (ROM) was assessed using goniometry. Results:The CAI group showed significantly decreased ankle strength at 60/sec across all motions.Notably, plantar flexion strength was 50.8% lower than that in the control group.ROM analysis revealed increased inversion ROM (9.11) and decreased eversion ROM (10.5) in the CAI group.EMG analysis demonstrated 34% higher peroneus longus activation during arabesque relev in CAI dancers than in the controls.Conclusion: Ballet dancers with CAI demonstrate specific neuromuscular adaptations, including decreased isokinetic strength at low velocities, directional ROM imbalances, and compensatory muscle activation patterns.Rehabilitation programs should focus on low-velocity strength training, correcting frontal plane ROM imbalances, and functional peroneus longus training integrated with ballet-specific movements.