Do your knees bother you with daily tasks such as walking, stairs, bending/squatting or with your daily exercise program? If you live, or have previously lived, an active lifestyle, you may be familiar with knee pain. Or, you may just have been unfortunately blessed with arthritic changes in your knees and have pain without any specific injury. I have some information that your knees could greatly benefit from: Strengthen your hips! Knee pain is one of the most common complaints of pain and discomfort, and it may not be enough to only perform knee strengthening exercises. Yes, it's vital to have strong hamstrings and quadriceps, but it's also important to have strong hip rotators and hip extensors (gluteus maximus). Knee pain could be caused by a number of different pathologies, but regardless of the cause of your knee pain, you should still work on improving the strength and endurance of your hips!
The knee is comprised of 4 main structural ligaments: the MCL, LCL, ACL and PCL. These ligaments are primarily responsible for maintaining stability of the knees but they also have the help of the quadriceps and hamstring muscles, which can decrease the forces the knee has to dissipate. A strong knee is defined as having all major ligaments intact, with the good tone and flexibility in the muscles that cross the knee. A comprehensive program will involve exercises to address each muscle that crosses the knee, i.e., hamstrings, quadriceps, gastronemius(calf), and with this new information, the muscles of the hip. Simple exercises can be performed to challenge both the knees and hips at the same time. Don't think of them as separate muscles requiring many different exercises, but rather think about performing compound movements that will challenge both groups.
The field of treating and preventing injuries has come out with some interesting research in the past decade. Currently, there is good research placing a strong relationship between the knees and hips. A recent article published states that "abnormal motion of the femur can have a direct effect on tibiofemoral [knee] joint mechanics and strain soft tissue restraints that bind the tibia to the distal end of the femur." In a clinical review by Christopher Powers from the University of Southern California titled, “The Influence of Abnormal Hip Mechanics on Knee Injury: A biomechanical perspective”, he reviews the evidence to support that the hip should be strengthened in conjunction with the knees. In the article, he states that: "During load phase of gait, excessive hip adduction and internal rotation can cause knee joint center to move more medially relative to the foot resulting in dynamic knee valgus." This dynamic knee valgus is essentially when you jump and land with your knees knocking or coming together. This has been correlated to serious knee injuries and should be avoided. The hip motions that we perform while we move and exercise, i.e., walking, climbing stairs, jogging, and cycling, etc. are done in a dynamic environment. This means we should consider strengthening our hips in a dynamic fashion as well, or in other words, as we move. Some suggestions for this are resistive band walks with both hip and knee flexion, split squats with a medial knee pull, or standing single leg trunk rotations. If you need assistance in the above exercises, contact a knowledgeable professional.
Some common knee injuries that result from weak hip muscles are: ACL tears during landing, Iliotibial band syndrome, and patellofemoral dysfunction. If you are experiencing knee pain, don't be surprised if the first thing your physical therapist does is instruct you in some hip strengthening exercises. I always include some type of hip strengthening exercises with my knee patients regardless of the reason for needing PT. If you don't have any knee pain, add some hip exercises to your program to reduce the risk of injury. If you need treatment for knee pain, or have any questions about the above, feel free to email me at Mike@jointventurespt.com
Mike Pellegrino DPT, CSCS
Physical Therapist/Performance Trainer