In order to investigate the effect of unilateral muscle weakening on the stress distribution in the growth-plates (GPs) of an adolescent idiopathic scoliosis (AIS) spine, the equivalent loads (as an alternative to in vivo loading conditions), estimated by our previously-validated trunk musculoskeletal (MS) model of AIS spine [1], were applied on the finite element model of GPs of L1 through L4. Results showed that weakening of the concave-side multifidus lumborum (MFL) and longissimus thoracis pars thoracic (LGPT) muscles rendered a reduction of about 25% in the compressive von Mises stress on the concave side of GPs, which can decelerate the deformity progression during growth.