Why Does Your Knee Hurt More Running Downhill?
Knee pain while running, unfortunately, isn’t unusual, but increased pain, specifically when running downhill, tells us more details about how your knee is being loaded. The short answer is that running downhill requires more work from everything on the front half of your leg to help slow you down and prevent you from falling forward. This includes your quadriceps and patellar tendon (right below your knee cap). The change in force often leads to altered movement patterns and more stress on structures that may not be ready to handle the load.
Downhill Running Changes the Forces at the Knee
When you run downhill, your body needs to move forward while also controlling the descent. Your muscles and joints act like breaks, but we want them to be smooth and controlled breaks, not quick and jerky.
Running downhill requires eccentric muscle contraction (muscle lengthening under load) of your quadriceps to help slow you down. This is combined with increased compressive forces at the knee joint and increased load at the patellar tendon, which connects your tibia (lower leg) to your kneecap and helps with knee extension (straightening).
Controlled eccentric work is much more fatiguing than concentric work (muscle shortening). Increased eccentric demand means more force is transmitted through the knee itself.
Common Knee Conditions Running Downhill
Patellofemoral Pain Syndrome (PFPS)
This is often known as runner’s knee or jumper’s knee and is associated with pain just below the knee cap at the patellar tendon. It is linked with an overuse of the patellar tendon, impaired tracking of the patella (knee cap), and a lack of eccentric control during running.
Iliotibial Band Syndrome (ITB)
IT Band Syndrome is associated with pain at the outer side of the knee and is aggravated with repetitive hip flexion and downhill running. It is also associated with a cross-over pattern in gait, meaning people who run with an extremely narrow base of support, almost like they are running on a balance beam. This causes the gluteal muscles to not do their job and causes an overutilization of the hip flexors, which translates to the IT Band.
Quadriceps Tendinopathy
This is very similar to patellofemoral pain syndrome in terms of causes. The pain is right above the knee cap where the quadriceps muscles become tendons. These tendons can become overworked and irritated just like the patellar tendon.
Running Techniques that Can Make Things Worse
The goal is never to make you run like a textbook. We all have different anatomy, and sometimes someone's running gait can create problems that didn’t exist prior. However, there are a few key running form corrections that I will make, because the research shows they increase the likelihood of injury.
Narrow Base of Support - this can be lumped together with hip drop, because they usually occur together. If you are running like you’re running on a balance beam, it can be challenging to have your glutes do their job to help you. This can be where we also see a hip drop, which can indicate your glutes need more strength to support your running. Typically, these go together and are correctable with some running drills and glute strength!
Cadence and Overstriding- the research shows a cadence of <165 steps per minute leads to an increased likelihood of injury. This is because with a cadence that low, you are likely overstriding, or landing with your foot too far ahead of your center of mass. This impairs your braking forces, which we talked about earlier at the knee. Again, this overactivates your hip flexors and impairs your glutes’ ability to do their job - to help you drive. Ideally, your cadence is >165 steps per minute, and your foot is landing underneath your hip.
What Can You Do About It
Work on ensuring your running cadence is >165 steps per minute, and your foot is landing underneath your hip, not in front of you. Think about shorter steps and more of them.
Work on not crossing over midline when running. Imagine a rope on the ground, and your feet need to stay on either side of it without touching the rope.
Work on eccentric knee strength: slow step-downs and slow split squats.
Work on glute stabilizing strength; single-leg strength, side steps, and lateral lunges.
Conclusion
Knee pain during downhill running has a lot to do with the change in the force required at the knee when running downhill compared to uphill or on flat ground. However, this doesn’t mean you should live with the pain. There are simple strength exercises and running drills that help put you in a better position for success.
