When a new client comes in with a knee pain, eight out of ten times I’ll start my exam at the hip. Seven out of those eight times, my client looks at me like I’m crazy. I think it’s time I reveal the method to my madness. Running is all about angles. What is the best angle for each joint to decrease injury? What is the best angle of your posture to produce the most efficient gait? Knee pain or patellofemoral pain is dependent on how knee and hip angles effect each other.
A recent study looked at knee angles and how they can change depending on hip abductor strength. The study looked at the strength differences and the knee mechanics of 15 symptomatic subjects versus 10 asymptomatic subjects. They found that the symptomatic subjects had weaker hip abduction. In addition, the subjects with knee pain had more angle variability within their stride at the knee. The symptomatic subjects performed ONLY two exercises every day for 3 weeks.
After the 3 weeks the symptoms improved, and so did the stability of the knee angle. Hip abduction strength is responsible for keeping your limbs aligned directly under your hip. If there is a weakness here, the knee joint will become less stable. This study found that the more variability there is in the angle, the weaker the hip abduction is, meaning you are more likely to have knee pain. So what does this mean for you? Think more about how much your knee is moving laterally through your stride and less about the angle you see on the photo your friend posted from this weekend’s run.
Changes in Knee Biomechanics After a Hip-Abductor Strengthening Protocol for Runners with Patellofemoral Pain Syndrome. Journal of Athletic Training. 2011;46(2)142-149.
Dr. Kathleen Leninger, PT