Many studies show decreases in muscle strength around the replaced hip even two years after the operation. With an exercise program, muscle strength improves from before to after the operation. An even better measure is to compare muscle strength from side to side before and after the hip replacement.

The joint implant can come loose when muscles are weak or when they function poorly. Muscle weakness leaves the joint unstable and unprotected. A supervised exercise program is advised for as long as possible even up to two years after the operation. This will protect the joint and improve function.

Doing the same exercises may not be best. A recent study showed exercises given early after hip replacement should be advanced to weight-bearing exercises. The best time to move on to this phase is four months after the operation. The patient must be able to stand on one leg without pain. The leg shouldn't give way or collapse.