For children to be able to run and play like normal, they need to develop their gross motor skills. Because of physical characteristics associated with T21, which include hypotonia (low muscle tone), ligamentous laxity (looseness of the ligaments that causes increased joint flexibility) and decreased strength, children with T21 do not develop those motor skills like a normal child does. Due to this, a lot of T21 children find ways to compensate for their physical disabilities which leads to improper muscle development, pain in the lower body and an abnormal walking pattern. Physical therapy helps to develop optimal movement patterns that will allow them to have proper posture, walk efficiently, and be able to exercise and run throughout the course of their life.