A muscle contracture is a permanent shortening of a muscle or tendon in the human body in response to continued hypertonic stress exerted on that muscle or tendon, such as constant spasticity. Contractures are most often seen in the tightest muscles of people with conditions like spastic cerebral palsy. Contractures can't be stretched or exercised away once they occur; they need orthopedic surgical intervention to be corrected. One focus of physical therapy and occupational therapy exercise in people with spasticity is usually to try to prevent contractures from occurring so that all muscles can continue to be voluntarily stretched.