The purpose of this case study was to describe the three-dimensional biomechanics of common ballet exercises in a ballet dancer with ischial tuberosity apophysitis. This was achieved by comparing kinematics between the symptomatic (i.e. ischial apophyseal symptoms) and contralateral lower limbs, as well as via reported pain. Results suggest consistent differences in movement patterns in this dancer. These differences included: 1) decreased external rotation of contralateral hip, hence a decreased hip contribution to 'turn out'; 2) increased contralateral knee adduction and internal rotation; 3) an apparent synchronicity in the contralateral lower limb of the decreased hip external rotation and increased knee adduction; and 4) minimal use of ankle plantar/dorsiflexion movement for symptomatic side. Pain related to the left ischial apophysitis was associated with reduced amplitudes especially in fast ballet movements that required large range of motion in flexion and adduction in the left hip joint. These findings suggest that ischial apophysitis may limit dancer's ballet technique and performance.