If you or someone you love has knee osteoarthritis, you’ve probably been told to stay active, but no one ever tells you which activity works best. A groundbreaking 2025 study published in The BMJ has finally answered that question with the largest and most rigorous analysis of its kind.
Here’s what you need to know.
What Is Knee Osteoarthritis and Why Does Exercise Matter?
Knee osteoarthritis (OA) is one of the most common chronic joint diseases in the world. It causes pain, stiffness, and a gradual loss of mobility that can seriously impact everyday life. Nearly 30% of adults over 45 show signs of it on imaging, and half of those experience significant symptoms.
While medications and surgery exist, exercise has long been recognized as a cornerstone of management. It builds lower limb muscle strength, improves joint range of motion, and supports neuromotor control, all of which reduce pain and improve how well you move.
The problem? Until now, doctors and patients didn’t have clear guidance on which type of exercise to prioritize. Should you walk? Stretch? Do tai chi? Lift weights? Swim?
The Study: 217 Trials, 15,684 Patients
Researchers from Zhejiang University and an international team of collaborators conducted a systematic review and network meta-analysis, the gold standard for simultaneously comparing multiple treatments. They analyzed 217 randomized controlled trials involving 15,684 participants with knee osteoarthritis.
Six exercise types were compared:
- Aerobic exercise (walking, cycling, swimming)
- Strengthening exercise (resistance training)
- Mind-body exercise (yoga, tai chi, pilates)
- Neuromotor exercise (balance and coordination training)
- Flexibility exercise (stretching, range-of-motion work)
- Mixed exercise (combinations of the above)
Outcomes were tracked at three time points: short-term (4 weeks), mid-term (12 weeks), and long-term (24 weeks). The key outcomes measured were pain, physical function, gait performance, and quality of life.
The Winner: Aerobic Exercise
Across nearly every outcome and every time point, aerobic exercise came out on top, and the results were not marginal.
For pain relief: Compared with a control group, aerobic exercise produced large reductions in pain at both the 4-week and 12-week marks, with moderate certainty. In plain terms, people who did aerobic exercise felt less pain meaningfully within a month, and that benefit persisted at three months.
For physical function, aerobic exercise led to large improvements in participants’ ability to move and perform daily tasks at short-, mid-, and long-term follow-up. It was the only exercise type to show functional benefits across all three time points.
For gait (how you walk): At mid-term, aerobic exercise was again among the top performers, helping people walk better and more confidently.
For quality of life: Aerobic exercise produced a large improvement in quality of life at the 4-week mark, the strongest effect of any exercise type at that time point.
Overall, the researchers used a statistical ranking method called the surface under the cumulative ranking curve (SUCRA), and aerobic exercise scored a mean of 0.72 across all outcomes, consistently the highest among modalities.
Other Exercises Still Have a Role
Aerobic exercise leads, but that doesn’t mean other modalities should be ignored. The study found several notable findings for different exercise types:
Mind-body exercise (think tai chi or yoga) led to a substantial improvement in physical function at the 4-week mark, making it an excellent option for those who may not tolerate high-impact aerobic work early on.
Neuromotor exercise training focused on balance and coordination showed the strongest gait improvement at 4 weeks. For older patients at risk of falls, this is clinically important.
Strengthening exercise and mixed exercise both showed large improvements in function at mid-term (12 weeks), making them solid choices for building lasting capacity.
Flexibility exercise showed a potential benefit for long-term pain reduction at 24 weeks, suggesting that regular stretching may help sustain gains over time.
Is Exercise Safe for Knee OA?
A concern many patients have is whether exercise might worsen joint pain or cause injury. The study addressed this directly. Of the 217 trials, 40 reported data on adverse effects. Crucially, no exercise type was associated with a significantly higher rate of adverse events than the control group. Confidence intervals were wide (indicating uncertainty), but the overall picture was clear: exercise is safe.
What This Means for You
If you have knee osteoarthritis, this research gives you a practical, evidence-backed starting point:
Start with aerobic exercise. Activities like brisk walking, cycling on a stationary bike, or swimming are excellent choices. They’re low-impact, accessible, and now backed by the most comprehensive research on exercise for knee OA.
Tailor it to your needs. If aerobic exercise isn’t possible due to pain or mobility limitations, mind-body exercises like tai chi are a legitimate and effective alternative, particularly in the early weeks. Neuromotor exercises are especially useful if balance and fall prevention are concerns.
Don’t expect overnight results, but please keep going. The benefits of aerobic exercise were already visible at 4 weeks and grew stronger by 12 weeks. Consistency matters.
Talk to a healthcare professional. An individualized exercise plan that accounts for your fitness level, comorbidities, and personal preferences will always produce better long-term adherence and outcomes than a generic one-size-fits-all program.
Why This Study Is Different From What Came Before
Previous reviews in this space had significant limitations: they typically examined only a single time point, used outdated methodological tools, and didn’t cover the full range of exercise types. The last major network meta-analysis in this field was published in 2019, with data ending in 2017.
This 2025 BMJ study addressed those gaps by evaluating short-, mid-, and long-term outcomes separately, using the updated Risk of Bias 2 (RoB 2) assessment tool and applying the rigorous GRADE framework to rate the certainty of each finding. It also nearly doubled the number of trials included compared to the 2019 analysis.
The result is the most current, comprehensive, and methodologically sound guidance available on exercise for knee OA.
The Bottom Line
You don’t need expensive medications, complicated devices, or surgery to start managing knee osteoarthritis more effectively. A consistent aerobic exercise routine, such as walking, cycling, or swimming, is supported by 217 randomized controlled trials and over 15,000 patients as the most effective exercise intervention.
Move more, move smarter, and move often. Your knees will thank you.
References
Yan L, Li D, Xing D, et al. Comparative efficacy and safety of exercise modalities in knee osteoarthritis: systematic review and network meta-analysis. BMJ 2025;391:e085242. https://doi.org/10.1136/bmj-2025-085242