Encountering a knee injury as a runner is almost inevitable. Knee injuries are so common among the running community that there’s an actual condition named for it: Runners Knee (I never said the medical community was clever). Your knee is the meat sandwiched between two pieces of bread: the ankle and hip. At first glance we think of the knee is a simple hinge joint that flexes and extends, but upon some digging you’ll learn that smaller, less obvious movements in the frontal (inwards and outwards) and transverse (rotation) planes do occur. The knee outsources the duties to control these motions, transferring responsibility to the knee and ankle. Our run form also influences how we load our body. Simple changes not only make sense mechanically and anatomically, but the research is beginning to justify the change.
Excessive rotational and inward knee motion may result in knee pain, but the true cause often arises from factors that are independent of the knee itself. Unlike the knee, our hip is a ball and socket joint that allows freedom of movement in multiple planes. Having the most freedom of movement throughout the lower extremity comes with responsibility. Your hip muscles, primarily the glutes, are responsible for controlling your hip range of motion. Poor control results increased motion that equates to downstream motion—primarily at the knee and ankle.
A study published in The Journal of Sports Physical Therapy found that women suffering from Patellofemoral Pain Syndrome (Runner’s Knee), generated 24% less hip external and 26% less hip abductor torque when compared to controls.1 Another study conducted in 2009 found that women with patellofemoral pain syndrome demonstrated lower eccentric hip abduction and adduction peak torque values when compared to that of controls.2 The studies are countless, really. Over and over you’ll find research pointing your knee pain back to hip weakness. Without citing a handful of other articles, some of which are highlighted here, hip strength has been found to not only affect the knee, but also the ankle. It should be fairly obvious that the best jumping off point is a targeted, runner-specific approach to hip strength.
For an encompassed approached to treating knee pain we can also look to our run form. High landing forces paired with the repetitive nature of running can be a drag on your knees, particularly for master runners; however, research has begun to indicate that we may be able to transfer force from our knee to its southern neighbor—the foot and ankle. Kulmala et al found that runners with a natural forefoot strike pattern demonstrated lower patellofemoral stress compared to heel strikers.3 It’s not all good, though. Another study found forefoot strikers to experience greater forces to the Achilles Tendon.3 That force has to go somewhere, right? Another recent research study identified forward lean as a possible change that could reduce stress at the knee. Teng and Powers found that peak stress at the patellofemoral joint was significantly lower when incorporating forward lean.4 Both of these studies make sense anatomically.
A good forward lean shifts our center of mass forward, decreasing the bending force at the knee. With decreased bending force comes less requirement from the quad to control said force. The result? Less compression force between your knee cap and the thigh bone (femur).
You don’t have to look far to find a fellow runner with knee pain. Our knees are often the voice for impairments at other areas. Unfortunately, that voice is pain. Knee pain is an epidemic of sorts in the running community; however, there are advantages of an injury with widespread influence. Our medical and scientific has responded with countless research studies and articles that help us better understand how we can prevent and manage pain.
1. Bolgla L. Malone T. Umberger B. Uhl T. Hip Strength and Hip and Knee Kinematics During Stair Descent in Females With and Without Patellofemoral Pain Syndrome. J Orthop Sports Phys Ther. 2008;38(1):12-18
2. Boling Michelle, Padua Darin , Creighton Alexander. Concentric and eccentric torque of the hip musculature in individuals with and without patellofemoral pain. J Athl Train. 2009 Jan-Feb; 44(1): 7–13.
3. Juha-Pekka Kulmala, Janne Avela, Kati Pasanen, Jari Parkkari. Effects of striking strategy on lower extremity loading during running. Br J Sports Med 2013;47:10.
4. Teng Hsiang-Ling, Powers Christopher. Sagittal Plane Trunk Posture Influences Patellofemoral Joint Stress During Running. JOSPT 2014;44:10.