Chronic knee pain afflicts millions of people and is the second leading cause of pain in the United States. Whether from injury or regular wear and tear, knee pain can affect your mobility and wreak havoc on your quality of life.
The knee and the hip are two of the most stressed joints in the body, but while hip pain is usually characterized as dull and aching, knee pain is often sharp and piercing.
“Maintaining healthy knees requires two things: flexibility and strength,” Lisa Zaun, a physical therapy assistant and inpatient joint replacement specialist, told The Epoch Times.
The Muscle Groups of the Knee
The knee muscles allow four different movements—flexion, extension, medial rotation, and lateral rotation—which are all critical for walking, running, and climbing, as well as helping to maintain balance.Quadriceps
The four key quadricep muscles are:- Rectus femoris—attaches to the kneecap and helps straighten the knee and bend the hip.
- Vastus medialis—runs along the inside of the thigh and connects the thigh bone to the kneecap, helping straighten the knee while stabilizing the kneecap during movement.
- Vastus intermedius—situated on the front and middle of the thigh, allows extension of the knee.
- Vastus lateralis—the largest and strongest of the quad muscles, located on the outside of the thigh. It attaches to the base of the kneecap and also helps straighten the knee.

Hamstrings
The three hamstring muscles are:- Biceps femoris—attaches to the top of the tibia (shinbone) and is primarily involved with bending the knee, but also enables hip extension.
- Semitendinosus—inserts on the upper part of the tibia and contributes to hip extension, internal rotation, bending of the knee, and stabilization of the pelvis.
- Semimembranosus—inserts on the tibia and is responsible for the extension of the hip, bending of the knee, and internal rotation of the leg.

Common Causes of Chronic Knee Pain
Chronic knee pain is often defined as pain that lasts for more than 12 weeks. Many of the things that cause pain in otherwise healthy knees can be attributed to functional patterns and muscle weakness, Zaun said.Functional patterns
The knee has to endure four pounds of force for each pound of body weight. Even 30 pounds of additional weight can force the knees to contend with 120 pounds of additional force.- Excessive running or jumping can cause considerable compressive forces on the knee.
- Prolonged kneeling, especially if repeated on a daily basis.
- Twisting or rotating over planted feet stresses the knee joint.
Muscle Weakness
Knee pain can also originate from muscle weakness, Zaun said. For example, weak muscles are a leading cause of knee injuries, so by strengthening your quadriceps and hamstrings, you'll help the muscles around your knees work more effectively, providing greater balance and stability.Exercises to Prevent Chronic Knee Pain
Zaun recommends bodyweight exercises for strengthening because they are easy to perform anywhere, requiring little to no equipment. When performed properly, these exercises can be both challenging and highly effective.Standing Hamstring Stretch
The hamstring stretch is an excellent way to decrease hamstring tightness, which will decrease tension in the back and knees.
Standing Quad Stretch
Tight quadriceps muscles can affect how you stand, walk, and sit and can lead to knee pain. This stretch allows you to keep the quadricep muscles stretched and loose.
Wall Squats
Weak quadriceps can allow the kneecap to fall out of alignment during walking, running, and bending. Wall squats strengthen your quadriceps, providing greater control of the kneecap. For best results, place a large exercise ball behind your back to help reduce friction and make this exercise easier.
Wall Squats With Ball Squeeze
This modification of the basic wall squat still works the quadriceps but with a specific focus on your vastus medialis, which plays the most critical role in controlling the kneecap during movement. This exercise is recommended once you’ve mastered the basic wall squat.This exercise can be considerably more fatiguing than basic wall squats, so do what you can at first and increase as possible.
Good Mornings
The hamstrings are often overlooked when exercising, and weak hamstrings can both decrease alignment and increase the negative effects of biomechanical forces on the knee. This exercise is easy and specifically strengthens the hamstrings.
Zaun recommends this simple exercise to build stronger hamstrings and increase knee stability.
A little care goes a long way when it comes to your knees. Performing these simple exercises at least three times per week can help you strengthen the muscles of the upper legs and help to keep your knees pain-free.