Cycling and swimming for knee arthritis: how to set up and build up

What does the research say about aerobic exercise for knee arthritis?

Aerobic exercise came out on top in the biggest recent study, a 2025 network meta-analysis in the BMJ. It pooled 217 randomized trials with 15,684 people and compared broad types of exercise: aerobic, strengthening, flexibility, mind-body, neuromotor (balance and coordination) and mixed programs. Against no exercise, the aerobic programs helped pain, function, walking ability (gait) and quality of life, and the authors rated that evidence as moderate certainty (Yan and colleagues, 2025). They suggest aerobic exercise as a first-line treatment where the aim is better function and less pain.

Two things are worth knowing before you read the headlines. The study ranked aerobic exercise as one group, so it does not say cycling beats swimming or walking. The BMJ press release gave walking, cycling and swimming as examples of aerobic exercise, but the study did not compare them with each other. And only 40 of the trials reported side effects at all, and in those the authors found no clear difference between exercise and the comparison groups.

None of this means you should drop strengthening. The knee osteoarthritis program is built on it, and most people do best with both.

Is cycling good for knee arthritis?

For most people, yes. A meta-analysis of stationary cycling trials in knee osteoarthritis found it reduced pain and improved function in sport and recreation, though the effects on stiffness and everyday tasks were less clear (Luan and colleagues, 2021). In one trial, people with mild to moderate knee arthritis who did 12 weeks of group indoor cycling walked faster and had less pain after a six-minute walk than a control group (Salacinski and colleagues, 2012). It was a small trial of 37 people.

Why does it suit an arthritic knee? You sit, so the bike carries your body weight, and nothing lands. In a study using measuring implants in nine people with knee replacements, the force through the knee while pedaling stayed below the force of walking, rose as the pedaling got harder, and was lower at a quicker cadence (Kutzner and colleagues, 2012). Replaced knees are not arthritic ones, but the message is useful: spin lightly rather than push hard.

How to set up the bike

1. Saddle height first. Sit on the bike with the pedal at its lowest point. Your knee should be slightly bent, not locked straight and not deeply bent. A review of saddle height research suggested about 25 to 30 degrees of knee bend at that point (Bini and colleagues, 2011). For most people that looks like a soft knee with the ball of the foot on the pedal.
2. Resistance next. Start at a level where you could hold a conversation. If you have to stand on the pedals or grind, it is too heavy.
3. Cadence. A smooth, steady spin is kinder to the knee than slow, heavy turns.

If your knee will not bend far enough yet to take the pedal over the top, rock the pedals back and forth through the range you have, or raise the saddle a little. The heel slides in the list below work on that bend.

How much to do

Many programs start with 10 to 15 minutes at an easy level, 2 or 3 times a week, then add a few minutes each week. That is a common clinic starting point rather than a dose tested in trials, and your physio will adjust it. The World Health Organization advises adults, including people with long-term conditions, to build toward 150 to 300 minutes of moderate activity a week (Bull and colleagues, 2020). Cycling, swimming and walking all count toward that total.

Is swimming good for knee arthritis?

Yes, and you do not need to swim lengths to get the benefit. A Cochrane review of 13 trials with 1,190 people found that a course of up to 12 weeks of exercise in water probably improves pain and disability a little in knee and hip osteoarthritis, measured straight after the course (Bartels and colleagues, 2016). The trials did not describe their exercises in enough detail to say which water program works best. The review describes this kind of exercise as usually done in warm water, at 32 to 36°C (about 90 to 97°F).

Ways to use the pool

• Walking in waist-deep or chest-deep water, forward, backward and sideways.
• A water exercise or aqua aerobics class, ideally one aimed at people with joint problems.
• Leg exercises holding the side, such as knee bends and slow kicks.
• Swimming with a gentle flutter kick, or a float held between the thighs so the arms do the work.

These are common physio suggestions rather than programs tested against each other. Choose a pool with a lifeguard on duty, and get out and sit down if you feel dizzy or faint.

A note on breaststroke

The breaststroke kick whips the lower legs out and round, which puts the inner side of the knee under strain. In a survey of competitive swimmers, pain on the inner side of the knee was common among breaststrokers (Rovere and Nichols, 1985). That was young athletes training hard, not people with arthritis, so treat it as a reason for caution rather than a ban. If breaststroke kick makes your knee ache, switch to flutter kick or use a float.

If you have had a hip replacement, get the go-ahead from your surgeon or physio before you try breaststroke kick. The kick swings the legs wide and turns the hips out, and many surgeons ask you to avoid that for the first months after some operations.

Which is better for knee arthritis, cycling or swimming?

Neither has been shown to beat the other, and the US guideline found no basis for ranking one form of exercise above another (Kolasinski and colleagues, 2020). Practical things decide it. A bike works in your living room in any weather. A pool takes more weight off the knee, but you have to get there. Plenty of people use both, plus walking, which has its own page: is walking good for knee arthritis.

Whatever you choose, judge it the next morning. Mild stiffness that has gone by breakfast is fine. A knee that is sorer or more swollen than the day before means cut the time or the resistance back a step. Bikes, pools and other kit are compared in best exercise equipment for knee arthritis, and exercises to avoid with knee arthritis covers what to change in the rest of your training.

Exercises that can help

Pedaling a full circle needs a good amount of knee bend, and pushing the pedals needs a strong thigh. These two help with both. Many programs use 10 to 15 slow heel slides, 2 or 3 times a day, and 2 to 3 sets of 10 to 15 seated knee extensions on each leg with a short hold, once a day. Your physio will adjust this.

Who should check first?

With a heart condition or high blood pressure, check with your doctor before you start. If you are pregnant and past the first three months, check with your physio before exercising flat on your back, as the heel slides are done lying down. Stop at once for chest pain or pressure, dizziness or feeling faint, a racing or irregular heartbeat, or being far more out of breath than the effort should cause. If chest pain does not ease quickly with rest, call emergency services; the warning list below gives the full set of signs.

After a knee fracture or knee surgery, including a knee replacement, follow your surgeon's or physio's plan, and start cycling and swimming only when they have cleared you. Cycling after a knee replacement follows your surgical team's plan first; the knee replacement rehab program explains the stages.

Related exercise programs

• Knee osteoarthritis
• Total knee replacement rehab

Common questions

References

1. 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
2. Luan L, Bousie J, Pranata A, Adams R, Han J. Stationary cycling exercise for knee osteoarthritis: a systematic review and meta-analysis. Clinical Rehabilitation. 2021;35(4):522-533. https://doi.org/10.1177/0269215520971795
3. Salacinski AJ, Krohn K, Lewis SF, Holland ML, Ireland K, Marchetti G. The effects of group cycling on gait and pain-related disability in individuals with mild-to-moderate knee osteoarthritis: a randomized controlled trial. Journal of Orthopaedic and Sports Physical Therapy. 2012;42(12):985-995. https://doi.org/10.2519/jospt.2012.3813
4. Kutzner I, Heinlein B, Graichen F, et al. Loading of the knee joint during ergometer cycling: telemetric in vivo data. Journal of Orthopaedic and Sports Physical Therapy. 2012;42(12):1032-1038. https://doi.org/10.2519/jospt.2012.4001
5. BMJ Group. Walking, cycling and swimming likely best exercise for knee osteoarthritis. Press release. 2025. https://bmjgroup.com/walking-cycling-and-swimming-likely-best-exercise-for-knee-osteoarthritis/
6. Bini R, Hume PA, Croft JL. Effects of bicycle saddle height on knee injury risk and cycling performance. Sports Medicine. 2011;41(6):463-476. https://doi.org/10.2165/11588740-000000000-00000
7. Bartels EM, Juhl CB, Christensen R, et al. Aquatic exercise for the treatment of knee and hip osteoarthritis. Cochrane Database of Systematic Reviews. 2016;(3):CD005523. https://doi.org/10.1002/14651858.CD005523.pub3
8. Rovere GD, Nichols AW. Frequency, associated factors, and treatment of breaststroker's knee in competitive swimmers. American Journal of Sports Medicine. 1985;13(2):99-104. https://doi.org/10.1177/036354658501300204
9. Kolasinski SL, Neogi T, Hochberg MC, et al. 2019 American College of Rheumatology/Arthritis Foundation Guideline for the Management of Osteoarthritis of the Hand, Hip, and Knee. Arthritis Care and Research. 2020;72(2):149-162. https://doi.org/10.1002/acr.24131
10. Bull FC, Al-Ansari SS, Biddle S, et al. World Health Organization 2020 guidelines on physical activity and sedentary behaviour. British Journal of Sports Medicine. 2020;54(24):1451-1462. https://doi.org/10.1136/bjsports-2020-102955

Written and checked by the PocketPhysio editorial team. Last updated 2026-10-16.

This page is general education, not a diagnosis or a personal treatment plan. See a physiotherapist or doctor for advice about your own situation.