Paraspinal muscle activity during symmetrical and asymmetrical weight training in idiopathic scoliosis.

CONTEXT Various studies report decreased muscle activation in the concavity of the curve in patients with scoliosis. Such decreased muscle-performance capacity could lead to sustained postural deficits. OBJECTIVE To investigate whether specific asymmetrical sports therapy exercises rather than symmetrical back strengthening can increase EMG amplitudes of paraspinal muscles in the concavity of the curve. DESIGN Cross-sectional. SETTING Laboratory. PARTICIPANTS 16 patients with idiopathic scoliosis. INTERVENTIONS Patients performed 4 back-strengthening exercises (front press, lat pull-down, roman chair, bent-over barbell row) during 1 test session. Each exercise was performed in a symmetrical and asymmetrical variant and repeated 3 times. MAIN OUTCOME MEASURE EMG amplitudes of the paraspinal muscles were recorded in the thoracic and lumbar apexes of the scoliotic curve during each exercise. Ratios of convex- to concave-side EMG activity were calculated. RESULTS Statistical analysis revealed that the asymmetrical variants of front press at the lumbar level (P=.002) and roman chair and bent-over barbell row at the thoracic level (P<.0001, .001 respectively) were superior in increasing EMG amplitudes in the concavity of the scoliotic curve. CONCLUSIONS Specific asymmetrical exercises increase EMG amplitudes of paraspinal muscles in the concavity. If confirmed in longitudinal studies measuring improvements of postural deficits, these exercises may advance care of patients with scoliosis.