Studies were carried out on the effect of lateral electric surface stimulation used to treat lateral idiopathic spinal curvature in children and youth upon ultrastructural changes in the muscles which take part in spine stabilization. The experiment was carried out for 3 months on 10 rabbits. It was found that this stimulation, performed for 9 hours daily for 3 months, resulted in both progressive and regressive changes. Deviations from a norm suggest that the stimulation process destroys the sensory part of the reflex arc and chronic destructure of motoric neuron. In addition to this, overstraining of the muscle fibres with work was reflected in fibre hypertrophy and changes in the mitochondria.