If you have ever seen a doctor for knee pain, chances are you were told to stop doing two things: running and squatting.
Both are nonsense, but I will focus on running for now.
Allow me to explain why I encourage my patients to run, with or without knee pain — even in the presence of arthritis.
Running helps cartilage
The common myth surrounding running and knee pain is the repetitive impact will wear away your cartilage, leaving you arthritic and destined for a knee replacement. Yet, research shows the exact opposite.
A recent systematic review asked the question, “what are the effects of running on the knee joint cartilage?” After closely evaluating 15 studies, the authors concluded running was beneficial for cartilage. They also tackled a common misconception about thinning cartilage.
When you provide compression to cartilage, it shrinks in size. The pressure from gravity squeezes many metabolic substances out, including water. This happens to our spines too, which is why your MRI will look different if you get it in the morning compared to the afternoon (MRIs are largely useless for musculoskeletal pain anyways). When you sleep, your joints decompress and the disc height returns.
Back to running.
If you look at knee joint cartilage 30 minutes after running, the cartilage will be thinner. However, if you wait 1–2 hours post-exercise, the thickness returns to pre-run levels. When comparing overall cartilage thickness between runners who run more than 30 minutes and those who run less than 30 minutes, there is no difference. There is no difference between people greater or less than 30 years old either.
But we still have evidence that cartilage thinning occurs during running. Since one of the primary roles of cartilage is shock absorption, wouldn’t thinning be an issue? Wouldn’t that expedite the development of arthritis? Not so much.
The compression during activity is beneficial.
More stress is not a bad thing
“If we could give every individual the right amount of nourishment and exercise, not too little and not too much, we would have found the safest way to health.” — Hippocrates
One of the greatest health myths is posture is a driver of pain. The body of research to date does not support this belief. Images of “proper” lifting technique and text neck are plastered on office breakrooms and shared by millions of people on social media. These are health misinformation.
The large misconception is increased stress on the body is by default damaging. Yes, bending your head forward or rounding your back does increase the strain on the muscles and ligaments surrounding the spine, but the level of strain is not a problem.
Your body can handle it.
Our bodies are remarkably adaptive and resilient. When exposed to stressors gradually, we benefit from them (i.e. exercise). It is no different with adopting various postures. It is also no different with running.
The impact forces experienced during running are greater than during walking. Research shows running creates forces up to eight times your body weight. These numbers are often used as scare tactics to ward people away from running.
Again, this is nonsense.
Like bone and muscle, cartilage responds and adapts to stress. When cartilage is compressed, it triggers adaptations that improve tissue strength and integrity. In early-onset arthritis, frequent compression can even stimulate limited self-repair.
The key is managing appropriate loads and intensity.
Take an individualized approach
We must keep in mind, most of these studies pertain to healthy individuals. Those with severe osteoarthritis lack any cartilage to protect bone. People with metabolic diseases, such as diabetes, have poorer healing capacity and cartilage quality, limiting the amount of stress the body can endure.
It does not mean running is only for healthy people, rather, everyone needs to adopt an individualized approach.
When I work with patients in the clinic, I evaluate the patient's training history and current health status. Exercise is gradually ramped and tracked to assess tolerance to load and stress. It is impossible to fully gauge a body's capacity in a single day or training session. You need to track your progress.
If you slept poorly the night before, your training tolerance will be diminished. Sleep, diet, and recent emotional and physical stress all impact our resilience and tolerance to future physical stress.
Ironically, one of the best ways to build our resilience, combat the negative effects of chronic disease, and reduce our pain experience is exercise.
Missing the forest for the trees
I have focused on cartilage thus far as it is the primary emphasis of health care providers, writers, and instagurus who spread the message running is bad for the knees. This is a reductionist approach.
Pain is a complex, multifactorial phenomenon. We do not feel pain strictly because of mechanical damage. Our emotional status, social support, and medical history all influence the pain experience. Expectations and beliefs about pain shape our pain sensitivity and severity. Damage alone is a poor predictor of pain.
This study with over 15,000 participants found pain reports did not differ between people with severe arthritis and those without arthritis. Similar can be found in other regions of the body, such as the shoulder, hip, and neck.
If arthritis and pain are the primary concern, then exercise is one of the best treatment options. As pain is a biopsychosocial phenomenon, we must consider all of the factors that influence it.
“I don’t run to add days to my life, I run to add life to my days.” — Ronald Rook
If you are a runner, you know nothing can replace running. The runner's high is addictive. Running provides a sense of freedom and accomplishment few other activities can. If someone is in pain, running may be the best prescription for them. If they identify as a runner and you try taking that source of identity from them, you are potentially harming them across the biopsychosocial spectrum, leading to a worsening of pain.
Running is a fantastic form of exercise which builds cardiovascular capacity, bone health, tissue resilience, and mental fortitude. If someone has pain with running, the answer is not to stop running. Instead, take a big picture approach.
Are their training parameters appropriate? Are they in the right shoes? Could emotional stress, diet, or sleep be playing a role?
If someone has knee pain and they are a runner, the first thought of a healthcare provider shouldn’t be, “how do I get them to stop running,” rather, it should be, “how can I help them continue running?”