Anyone who has knee pain knows exactly which activities they can and can’t do without exacerbating their problem! For some people walking can be a trigger, while for others it might require something more dynamic like running. To help you understand why walking and/or running may cause knee pain, you first need to understand how the parts of the body should move when engaging in these activities.

When you are walking or running, you must transfer weight from side to side as you step forward with alternating feet. Part of this weight transfer is possible because the feet have the capability to roll inward toward each other (i.e., pronate). When the foot pronates, the ankle rolls in with it, which in turn helps rotate the lower leg, knee and thigh toward the midline of the body. Simply put, the mobility of the foot and ankle enables the shin bones to rotate inward. The thigh bone which fits into the pelvis to form the hip socket, should also rotate inward in time with the lower leg.

How Do the Parts Affect the Whole?
So how can hip immobility cause knee pain? As you now know, movement of the foot enables the ankle, lower leg and upper leg to roll inward. If the hip lacks the mobility to turn inward, however, a tug-of-war ensues between the foot — which wants to turn the ankle and lower leg inward — and the upper leg (connected to the hip socket) which is not able to come along for the ride. The joint that bears the brunt of these opposing forces is the knee, since it connects the upper and lower leg and cannot move in two directions at once. This stress to the knee can lead to pain and dysfunction.

A primary cause of hip immobility is extended periods of sitting. Whether at a computer, driving, eating, playing video games and/or watching TV, prolonged sitting affects mobility of the hip and can, over time, lead to movement restrictions in the hip socket. Overdoing athletic movements that require only one or two ranges of motion for the hips, like bike riding or running, can also lead to muscle imbalances and subsequent hip immobility. This immobility of the hips can be a major contributor of knee pain.

Fix the Part to Mend the Whole
Assessing hip mobility, specifically the ability of the hip to rotate inward, is a relatively straightforward process. Lie on the floor and spread your legs about 18 inches to 2 feet apart. Try to turn both of your legs inward so the feet move toward each other (see Picture 1). Look to see if one leg cannot turn as far in as the other leg, or if both feel tight or restricted. Both legs should be able to turn in about 30°. In the example below, the person has almost an acceptable range of motion for her left leg, while her right leg is severely lacking the mobility to rotate inward.

Lying Leg Turn AssessmentLying Hip Mobility Assessment

If you lack mobility in either, or both, of your hips, this may be the cause of your knee pain (as well as other issues). Therefore, the first and most important goal is to release tension from the larger muscles that help control hip movement. There are many corrective exercises you can do to improve hip mobility, but the best strategy is to use a variety of self-massage techniques. Below you will find three simple self-massage exercises that can greatly improve the function and mobility of your hips. Performing these exercises on a regular basis will help your knees (and the rest of your body) feel and function better.

Corrective Exercises
Tennis Ball on Butt
The gluteus maximus muscle helps control rotation of the leg and the hip socket. Using a tennis ball to release and rejuvenate this muscle (and the other smaller muscles of this area) will enable the leg to rotate more freely in the hip socket and take stress and strain off the knees.

TB on butt

Lie on the floor with your knees bent and place a tennis ball under one side of your butt. Move around on the tennis ball to find a sore spot, stay there for 10 to 20 seconds as the tension releases, and then move to a new spot. Perform at least once a day for about 2 to 3 minutes on each side.

Tennis Ball on Hip Flexors
The hip flexor muscles originate on the lumbar spine, cross the pelvis and attach to the top of the leg. They help control rotation of the leg and hip socket. Performing the following self-massage technique with a tennis ball is an effective way to increase hip mobility and reduce knee pain.

TB on hip flexors

Lie face down and place a tennis ball under the front of your hip/leg and find a sore spot. Maintain pressure on the sore spot for 10 to 20 seconds until the sensation lessens, and then move the ball up and onto your lower abdominal region, releasing sore spots along the way from the top of the hip to just beside your bellybutton. (Note: Do not place the tennis ball on the sensitive areas just to the side of the pubic bone where the leg meets the groin.) Perform this exercise once per day for about 1 to 2 minutes each side.

Foam Roller on Side and Front of Leg
There are two other important structures on the upper leg that help control rotation of the hip and leg. The iliotibial band connects the gluteal muscles to the lower leg and the rectus femoris, which is a quadriceps muscle, originates on the pelvis and connects to the kneecap. These structures must be healthy and flexible to enable the hip and knee to work correctly.

FR on leg

Lie over a foam roller placed perpendicular to their upper leg. Roll your body to the side so the front and outside of your upper leg makes contact with the roller. Roll up and down on any sore spots you find. Do each leg for approximately 1 to 2 minutes every day.
Note: If the pressure of the foam roller is too much, you can regress this exercise by placing a tennis ball under the side and front of your leg, instead of the roller, while you are lying down.

Many of the largest and most powerful muscles of the body cross the hips and attach to the leg. Restrictions in these muscles affect the ability of the hips to function correctly and, subsequently, the amount of stress experienced by the knees. The simple hip mobility assessment and effective corrective exercise strategies outlined here can help you experience substantially less knee pain as well as improved performance.