Pain in the joints may be caused by genetics, wear and tear or injury. Exercise is often prescribed as a safe and effective method for treating a variety of knee and hip problems.
Strong muscles around a knee or hip take over some of the job performed by the joint. If your quadriceps, gluts, hamstrings and abdominal muscles are stronger, they’ll bear part of your body weight so your hips don’t have to do all the work. And strong quadriceps can relieve stress on the meniscus or knee cartilage by acting as shock-absorbers
How muscles work
Muscles work in opposing pairs—one relaxes while the opposing one contracts. When the pair of muscles is balanced in strength, they’ll hold joints in the optimal, most functional and least painful positions.
If you straighten your knee, the quadriceps on the front of your thigh contract, and the hamstring running down the back of the leg from the gluts relaxes.
Imbalances in the strength and flexibility of these paired muscles can cause joint problems and eventually result in injury. If the hamstrings are tight, your quadriceps may weaken because they aren’t able to contract fully. It’s important to exercise both pairs of opposing muscles equally to avoid joint stress from an imbalance.
Open- and Closed-chain exercising.
The chain refers to a series of body parts—hip, knee, ankle and foot. Open-chain exercises may be more effective for specific therapeutic goals, such as increasing quadriceps strength after anterior collateral ligament (ACL) injury to the knee. Sitting in a chair and extending your leg to strengthen the quadriceps is an open-chain exercise because your body is still as your leg moves.
A squat is a closed-chain exercise because your feet are stationary while the quadriceps do all the work. In general, physical therapists encourage closed-chain exercises because they involve more joints and muscles and help create stability around a joint.
Working with a physical therapist
Your physician may prescribe physical therapy for arthritic or injured joints. A physical therapist carries out specific instructions from your doctor. After evaluating the extent of your pain, ability to function, strength and endurance, the therapist may use ice, heat and massage to help relieve your pain and introduce you to a series of exercises to perform at home between visits.
Gait retraining Joint pain can disrupt your normal walk and restrict the normal range of joint movement and thereby weaken muscles. Additionally, your normal way of standing, walking or running may result in joint problems if muscle weakness, poor coaching advice or bad habits throw off your gait.
Though it may take years of walking with an abnormal gait before injury to the joints becomes apparent, joint injuries from improper running show up more quickly.
A physical therapist will analyze your gait and help you to walk more normally with the aid of a change in shoes or with exercises to strengthen muscles. The corrected gait may feel uncomfortable until you’ve had additional practice and continued instruction.
After knee or hip replacement, the tendency is to lean toward the leg that was operated on. Gait retraining helps you to relearn how to stand up straight and may begin in a pool, where the water’s buoyancy takes weight off the joint and reduces the fear of falling.
from Harvard Medical School Healthbeat, June 12, 2012