Written by: Leda McDaniel
Knee pain is quite common in runners and endurance athletes. In fact, by some estimates more than 70% of endurance athletes will have a bout of knee pain at some point! Knowing some common risk factors and underlying causes in endurance training and how to address them can go a long way in getting back on the roads, on your bike, or in the pool.
In Episode #6 of the More Than Miles Podcast, Physical Therapists Dr. Kate Mihevc Edwards and Dr. Kacy Seynders discuss common causes of knee pain, risk factors for knee pain, and most importantly, how to best treat knee pain based on your individual “kneeds,” as an endurance athlete.
As the common adage goes, “An ounce of prevention is worth a pound of cure.” This rings true regarding knee pain in endurance athletes! Because the incidence of knee pain is so high in endurance athletes, and there are some common patterns specific to knee pain in this population; knowing how to reduce injury risk at the knee could save you from putting your training or racing on hold.
One of the factors to consider when an endurance athlete has knee pain is a term called “interregional dependence,” or more simply, the knee is at the mercy of the hip and ankle. What this means is that deficits in strength or mobility at the hip or ankle (or low back and rib cage!) could place abnormal forces on the knee and lead to injury. Because of the common presentation of issues at the hip, ankle, or foot leading to knee pain, endurance athletes need to be aware that the knee joint itself is often not the “culprit” of knee pain but is more often the “victim” of a problem somewhere above or below it. Or, you could say that the knee is “at the mercy” of what goes on at the hip and ankle.
Let’s break down some of the common causes of knee pain.
Common causes of knee pain in endurance athletes include:
Lack of strength in hip muscles (quite common if hip abductors are weak)
Lack of mobility at the ankle (may place more force on the knee)
Poor footwear choices (shoe does not fit well or a runner is not replacing their shoes frequently enough)
Lack of mobility at the hip, lumbar spine, or ribs that could include poor breathing mechanics (could lead to poor biomechanics at the knee)
Runner is over or under pronating or the timing of pronation is abnormal in the running cycle
Poor biomechanics in running gait, swimming stroke, or biking form
Poor fit of bike in cyclist or triathlete
Poor training choices (i.e., “training errors”), such as increasing volume of training too quickly, changing terrain like adding a lot of hills training for running
Common Knee Pain Diagnoses:
One issue with diagnoses of knee pain is that (as Kacy discusses in the podcast episode), the terms that are used may tell you what tissue or area is hurting, but they do not necessarily tell you the exact cause of pain or how to fix it. With that said, most diagnoses of knee pain in endurance athletes are due to repetitive “overuse” or microtrauma vs. one specific traumatic event.
Common Diagnoses of Knee Pain in Endurance Athletes include:
IT Band Syndrome
Patellofemoral Pain Syndrome
“Anterior Knee Pain”
Patellar tendinopathy (or tendinitis)
Knee Pain that is “referred pain” or caused by issues at the hip or lumbar spine (low back)
How to treat knee pain:
As you can see, knee pain diagnoses are pretty broad and do not necessarily provide targeted information on what to do about that pain! Treatments for knee pain in runners and endurance athletes will depend more on what caused the issue in the first place vs. what specific “diagnosis” has been assigned to the athlete. As mentioned above, causes of knee pain often follow patterns based on areas above and/or below the knee that may be contributing to the problem. We might describe four broad categories of common patterns in endurance athletes. These are: 1- A Mobililty issue, 2- A stability (strength) issue, 3- A Form (biomechanics) issue, or 4- A external factor (“Training Error”: such as shoes, terrain, training volume etc.). Let’s take a look at each of these issues in a bit more detail.
What if an athlete is…
1. Lacking Mobility:
The knee is classified as a hinge joint and so primarily is designed to flex and extend (i.e., bend and straighten) with a small bit of rotation. So, if the ankle or hip are lacking mobility, the knee may become the “victim” of forces it is not designed to take because it is sandwiched in the middle. This may create some abnormal and problematic forces such as if the knee is forced to bend in (i.e., valgus force) or out (i.e., varus force). Common mobility issues that may contribute to knee pain are reduced dorsiflexion or pronation at the ankle, reduced hip internal or external rotation, or reduced upper back or ribcage mobility.
2. Lacking Strength:
As Dr. Kate says in the podcast episode, “Just because you run does not mean you have the leg strength that you need to avoid running injury!” In endurance sports, a little bit of lower body and core strength training can go a long way to reducing injury risk as well as helping an athlete address some of the causes of knee pain mentioned above. Common areas of lower body weakness in runners are hip abductor muscles, quadriceps muscles, and calf muscles.
3. Using Poor Biomechanics:
Running, biking, or swimming with poor biomechanics (i.e., poor “form”) could also contribute to knee pain. There are many ways that poor form, or poor biomechanics could impact endurance athletes and the ultimate way to address these form issues is to have a trained professional, like a physical therapist, watch the athlete do the specific movement (e.g., run, bike, or swim) to assess movement quality. One example of a biomechanical fault would be if a runner has poor timing of pronation, which could impact how much force is felt at the knee. In ideal running gait, pronation is part of what helps the body accept load and acts as a shock absorber from the forces transmitted from the ground to the foot and ankle, up to the knee, and further on up the body chain. If an athlete has poor timing of pronation or pronates too much or too little, shock absorption can be altered, and the added force felt at the foot and ankle, transmitted to the knee could increase injury risk at any of these areas.
4. Making “Training Errors”:
Just like in strength training or improving cardiovascular endurance, our body takes time to adapt to any given stimulus. If a runner increases mileage too quickly or suddenly increases the amount of hill training they are doing, this could increase injury risk because the body tissues will be experiencing increased forces in ways that don’t let them adapt! Also, if factors like footwear or terrain are changed too fast, this can increase injury risk as well. One point to note here is that running research tends to support the idea that the best shoe to run in is the one that is most comfortable for the athlete (not necessarily one that is matched to their “running mechanics”)!
How do physical therapists address knee pain in endurance athletes?
As already mentioned, treatment for knee pain will be individualized based on findings from a comprehensive, full body assessment of an athlete’s mobility, strength, mechanics, and training factors. The good news, as Dr. Kacy points out on the podcast episode, is that this does not necessarily mean an endurance athlete will have to stop training or stop running altogether! If working with a trained physical therapist (ideally one versed in endurance sports), an endurance athlete could likely keep training in some capacity as they work on the factors that may need some attention.
Hopefully, some of the information above has been helpful as you think about reducing your risk of knee injuries and what may be some potential causes if you are experiencing knee pain as an endurance athlete. As always, please take this blog post as general information, but this is NOT INTENDED AS MEDICAL ADVICE. If you are having knee pain that is severe or that does not resolve with some general “self-treatment,” strategies it may be best to seek out the help of a trained medical provider like a physical therapist or orthopedic doctor.
Check out the podcast episode for the full, in-depth discussion of knee pain in endurance athletes: