Knees Hurt? This Exercise Can Help.

New York Times

26-03-2025

Caitlin Berzok used to be scared of strength training. She occasionally exercised with ankle weights but worried that heavy lifting might slow her down or lead to injury.
In 2015, she got serious about running, progressing from shorter races to marathons, and just a year later she started having chronic knee pain. Soon, she could barely run a mile. Ms. Berzok, then 29, tried resting, stretching and working with a physical therapist, but nothing helped.
Then a new physical therapist had her try weight lifting with a kettlebell, starting light and eventually working up to 40 pounds. She'd leave a session drenched in sweat after wide-legged squats, curtsy squats, Bulgarian split squats, Romanian deadlifts and lunges. 'I never knew there were so many different types of squats,' Ms. Berzok said.
Within a year she was back to running marathons pain-free, and over the years she has kept lifting.
Frequent knee pain affects about 25 percent of adults. While a generation ago experts often recommended rest and ice to alleviate knee pain, evidence now suggests that strength training can reduce pain and increase range of motion.
'Stronger muscles help distribute the load more evenly across the knee,' said Dr. Nima Mehran, an orthopedic surgeon in Los Angeles, Calif., who specializes in the knee. Building muscles reduces the amount of stress on the joint, he said, and it can also improve alignment, which in turn helps prevent injury.
'People think that strength training will hurt their knees or cause further damage,' said Leada Malek, a physical therapist in San Francisco who specializes in sports medicine and the author of 'Science of Stretch.' But that's not actually the case, she said.
The key is to find movements you can do without severe pain and gradually build your strength and range of motion.
How Muscles Affect Knee Pain
While the knee joint itself doesn't have muscles, it has ligaments and cartilage and is stabilized by the muscles surrounding the joint: the quads, hamstrings, calves and hips.
These muscles power your body's movement, and they also act as shock absorbers, Dr. Malek said. Chronic knee pain — as opposed to an acute injury, which may require surgery — can often be resolved through strengthening, Dr. Mehran said. That's especially true for two of the most common types of knee pain.
The first is patellofemoral pain syndrome, also known as runner's knee, which presents as pain at the front of the knee. The second, osteoarthritis-related knee pain, often occurs in people who are around age 50 or older and can frequently lead to discomfort and stiffness surrounding the entire knee joint.
Dan Giordano, a physical therapist in New York City who treated Ms. Berzok, added that it's important to remember the hip muscles as well, since they play a significant role in reducing the strain on the knee joint.
Many of Dr. Mehran's patients are in their 50s and 60s with chronic knee pain and want to avoid knee replacements, but their pain is limiting their activities and quality of life. He advises those patients to first try strength training, he said.
'Knee replacement might be the final step,' Dr. Mehran said. 'But there's a whole ton more steps on that ladder before we get to the final step.'
How to Strengthen Muscles Around Your Knee
When it comes to managing chronic knee pain, Dr. Malek said the best approach is a progressive strength training program, which means adding weight or making the movements more difficult over time.
As Ms. Berzok found, one of the best knee strength exercises is the squat, which targets the quads, hamstrings, glutes, hip flexors and calves.
The key to squatting with knee pain is to start with a version of the movement that doesn't cause pain. If you can't achieve a deep squat, go as low as you can at first, starting with your body weight and slowly adding weight.
Focus on strengthening the muscles in your posterior chain, which include your glutes and hamstrings. When these muscles are imbalanced — for example, if your quads are significantly stronger than your hamstrings — it can increase your likelihood of knee pain and, in extreme cases, can even lead to a torn A.C.L., Dr. Mehran said.
To strengthen the glutes and hips, Dr. Malek recommended a leg bridge or clamshells, using your body weight, an exercise band or weights on the outside of your knee.
For a more challenging glute and hamstring movement, try a weighted hip thrust or the Romanian deadlift. Dr. Malek also recommends step-ups onto a box or stair.
What to Know About High-Impact Exercise
If your knee pain is sharp, new or the result of an injury, most experts recommend holding off on running, climbing or jumping — and switching to low-impact cardio like swimming or biking — at least until you can get a professional assessment.
However, Dr. Malek said it's not necessarily true that high-impact activities will always worsen knee pain, especially when dealing with osteoarthritis.
'It varies by person and their history of injuries,' she said. While experts agree that strength training is an effective way for almost everyone to prevent and treat knee pain, higher impact activities should only be done if they don't cause pain. If your knees can handle it, running and jumping won't necessarily further damage your knees, Dr. Malek said.
While it's certainly a matter of some debate among researchers, Dr. Mehran said there is some evidence that lifelong runners can develop thicker protective cartilage around their knees.
As for Ms. Berzok, by 2023 she could run a half marathon about 13 minutes faster than before her injury, even after having a baby in 2018.
'I think everyone should be strength training — especially women as we get older,' she said.