Knee Pain: Why Strength Training Helps

Written by INNER G

"Knee pain" has stayed one of the steady health searches in Canada all year on Google Trends, and sore knees are a common reason people stop exercising. For knee osteoarthritis, the research points the other way: the right exercise is a core treatment, not something to avoid.

This post covers what the newest Cochrane review found, which kind of exercise seems to help most, how often to train, and when to get your knee checked first.

Please read first. This post is general information, not medical advice. If your knee is hot, red or very swollen, locks or gives way, or you can't put weight on it after an injury, get medical care before you start a new program.

What the 2024 Cochrane review found

Cochrane reviews pool every good trial they can find on one question. The 2024 update on exercise for knee osteoarthritis included 139 trials with 12,468 people (Lawford et al., 2024).

  • Compared with no treatment or usual care, exercise improved pain by about 13 points on a 0 to 100 scale and physical function by about 13 points (56 and 54 trials).
  • Compared with a placebo or attention control, pain improved by about 9 points and function by about 11 points.
  • Added to another treatment like a weight loss diet or physical therapy, exercise improved pain by about 10 points more than that treatment alone.
  • Dropouts were no higher with exercise. Some comparisons found more side effects with exercise. In the older version of the review, the side effects reported were increased knee or low back pain, and no trial reported a serious one (Fransen et al., 2015).

How much exercise eased knee osteoarthritis pain

Average improvement in pain on a 0 to 100 scale at the end of the program. Dashed line = 12 points, the threshold the authors used for a change people notice.

vs no treatment or usual care56 trials, 4,184 people
13.14
Added to another treatment47 trials, 4,441 people
10.43
vs placebo or attention control28 trials, 2,873 people
8.7

Source: Lawford BJ, et al. Cochrane Database Syst Rev 2024;12:CD004376, 139 trials. Certainty of evidence: low for the first and third bars, moderate for the second. Read the review.

The authors were careful. Most trials couldn't blind people to the fact that they were exercising, the certainty of the evidence was rated low to moderate, and measured against the usual threshold for a change people notice (12 points for pain), they called the benefits of uncertain clinical importance. So the fair summary: exercise probably helps pain and function in the short term. The international OARSI guidelines list structured exercise and arthritis education, with or without dietary weight management, as core treatments for knee osteoarthritis (Bannuru et al., 2019).

An older Cochrane version found the effect on pain was similar in size to estimates for anti-inflammatory pills, and that part of the benefit lasted 2 to 6 months after programs ended (Fransen et al., 2015).

Why the muscles at the front of your thigh matter

The quadriceps, the big muscles at the front of the thigh, help control and cushion the knee every time you stand up, walk down stairs or sit down.

A meta analysis of 48 trials looked at which exercise programs eased knee osteoarthritis pain the most (Juhl et al., 2014). Two findings stood out:

  • Programs that focused on the quadriceps reduced pain more than general leg programs (effect size 0.85 vs 0.39).
  • Supervised exercise at least 3 times a week did better than less often (0.68 vs 0.41).

What made knee programs work better

Pain reduction compared with control groups, as effect sizes (standardized mean differences). Longer bar = bigger effect.

Quadriceps focusedthigh strength programs
0.85
General leg exerciselower limb programs
0.39
Supervised 3+ times a week
0.68
Supervised less often
0.41

Source: Juhl C, et al. Arthritis Rheumatol 2014;66(3):622–636, meta analysis of 48 trials in knee osteoarthritis. Read the study.

Aerobic exercise, strength training and performance exercise (balance and everyday movement drills) each helped by similar amounts in that analysis, and programs with one clear aim did better than ones that mixed everything together. The newer Cochrane review didn't find clear differences between exercise types, so the best program is a well designed one you'll actually keep doing.

What a knee friendly week can look like

You don't need to avoid your legs. You need the right dose and good form. Our coaches usually start with moves like:

  • Sit to stands from a box or bench, then lower the height as you get stronger
  • Step ups onto a low step
  • Wall sits or partial squats in a range that feels okay
  • Glute bridges and hamstring curls for the muscles behind the knee
  • Lunges later, once the basics feel steady

Some soreness while you build up can happen; increased knee pain was the side effect the older Cochrane review found reported. If pain is sharp, keeps getting worse from week to week, or your knee swells after sessions, ease off and talk to your doctor or physiotherapist.

How many coached sessions a week?

In a 48 trial meta analysis, supervised exercise at least 3 times a week eased knee pain more than less often (Juhl et al., 2014). Pick a number to see the matching Inner G membership.

Memberships are billed weekly, plus HST, with a 3 month commitment. Not sure yet? Try the $30 seven day trial first.

Train your knees with a coach in Vaughan

Supervision and a clear plan helped in the research, and that's how we coach. In our small group classes a coach adjusts every exercise to your knees, with a cap of 16 people per class. If you'd rather work one on one, see personal training in Vaughan. We also offer gentle strength coaching for joints and balance, and since OARSI pairs exercise with dietary weight management for knee osteoarthritis, our nutrition coaching can help.

Start with the $30 seven day trial: 7 days of unlimited classes for $30 (+ HST). Join by day 5 and your $30 is credited toward your membership.

Questions? Call (289) 536-8066 or email g-squad@innerg.ca.

References

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