Will Running and Other High-Impact Exercise Ruin Your Knees?

Running gets a bad rap. Despite its cardiovascular and fitness benefits, many people think running is harmful to joint health. Running is indeed a high-impact exercise, one where both feet leave the ground simultaneously. Yet there are some benefits to taking a run and doing so in moderation isn’t the joint destroyer that many people think.

Myth: Running Increases the Risk of Joint Problems

Despite the widespread belief that running harms joints, many experts disagree. In one study published in the Journal of the American Medical Association, researchers compared the joints of middle-aged runners to a control group who didn’t run. They did not find an increased incidence of osteoarthritis among the group who ran. Plus, the runners had higher bone density than the non-runners.

The increase in bone density in runners isn’t surprising. One of the benefits of running is its effect on bone health. When your feet strike the ground, the impact causes bone-producing cells called osteoblasts to lay down new bone. People who get more high-impact exercise, like running during adolescence and early adulthood, are less likely to develop osteoporosis later in life. There’s even evidence that high-impact exercise and strength training can boost bone density during middle to late adulthood.

Running May Help Joint Cartilage Repair

One determiner of joint health is healthy cartilage, connective tissue that covers the ends of bones, reduces friction, and helps keep your joints healthy. Osteoarthritis is caused by breakdown and damage to the cartilage that covers bones within a joint. You can avoid osteoarthritis by maintaining healthy cartilage and running may help.

How can running help you ward off osteoarthritis? The repetitive shock of impact helps cartilage stay healthy by stimulating the growth of new cartilage cells (chondrocytes). Because cartilage is avascular (lacks blood vessels), it relies on these chondrocytes to provide nutrients and remove waste.

Studies show that distance runners have more chondrocytes in their knee cartilage than people who don’t run regularly. This means their cartilage has a greater ability to repair itself. Some studies show that runners have thicker, healthier cartilage in their knees.

In addition, running strengthens and thickens the large quadriceps muscle, the muscle in the front of your thighs, to give your knee firmer support and protection against trauma and injury. It’s important to have strong quadriceps if you have knee arthritis.
In one small study, researchers measured the level of inflammatory chemicals called cytokines in runners during a session where they ran and during a control session where they didn’t run. After the running session, the participants had lower levels of cytokines whereas they didn’t change during the control sessions. Could running have anti-inflammatory activity for knee joints?

Also, running helps maintain healthy body weight. People who are overweight or obese have a higher risk of developing knee osteoarthritis. The more weight you carry, the more force it places on your knees when you walk or run.

There is evidence that at a competitive level running increases the risk of osteoarthritis, but these are runners who run long distances and train often. There’s little evidence that recreational runners have a higher risk of osteoarthritis and some evidence that odds are lower.

Running If You Already Have Arthritis

If you already have knee arthritis, running may not be in the cards if it causes pain. A good rule of thumb is if it hurts, don’t do it, or modify it. Depending on how severe your arthritis is, your doctor might recommend low-impact exercise to reduce trauma on your knees. If your physician says it’s okay to run, wear a pair of running shoes with good support and run on a softer surface, not a hard surface like concrete.

Find an area with a flat, even terrain. Running on uneven ground can be problematic for people with knee arthritis, so stick to running on flat surfaces whenever possible. If it is necessary to run on a hilly course, don’t try to pick up speed going downhill. Instead, walk down the hill at a steady pace and run uphill again.

Be sure to warm up and cool down. If you’re just starting, begin slowly and build your distance gradually over several weeks or months. Do a dynamic warm-up, and then start with an easy run at a slow pace, gradually increasing your speed. Listen to your body, and if something hurts, stop. After your run, cool down by walking for 5-10 minutes after the session. Don’t forget to stretch after cooling down from your run.

Vary the types of exercises you do by cross-training. Avoid running every day, no matter how much you love it, as you will be working your muscles and joints in the same way every day, leading to repetitive trauma. The same applies to other high-impact exercises that require jumping. Include strength training in your routine too to build strength in your quadriceps, glutes, and core. Thighs, glutes, and a core of steel will lower your risk of injury. Plus, strength training has health and fitness benefits you can’t get from running alone. Running does little to improve upper body strength.

The Bottom Line

Running won’t destroy your joints and running in moderation may even improve joint health. Plus, running has other health and fitness benefits. However, running might not be for you if you already have arthritis and it makes your joint pain worse. If that’s the case, you may be better served by getting a cardio workout with circuit training using low-impact exercises. Talk to your healthcare provider about your situation and what is best for your situation.

References:

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  • “Running with Knee Osteoarthritis – Osteoarthritis.” 05 Apr. 2016, blog.arthritis.org/osteoarthritis/running-knee-oa/.
  • “Running and Osteoarthritis: Does Recreational or ….” 31 May. 2017, jospt.org/doi/full/10.2519/jospt.2017.0505.
  • Alentorn-Geli E, Samuelsson K, Musahl V, Green CL, Bhandari M, Karlsson J. The Association of Recreational and Competitive Running With Hip and Knee Osteoarthritis: A Systematic Review and Meta-analysis. J Orthop Sports Phys Ther. 2017 Jun;47(6):373-390. doi: 10.2519/jospt.2017.7137. Epub 2017 May 13. PMID: 28504066.
  • “Running May Actually Be Good for Your Knees, Study Finds ….” 09 Dec. 2016, https://www.psychologytoday.com/us/blog/the-athletes-way/201612/running-may-actually-be-good-your-knees-study-finds.
  • “Running Actually Good For Knees, Study Finds – Study Finds.” 05 Dec. 2020, https://www.studyfinds.org/study-finds-running-knees/.

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