Key points
- You can exercise with bad knees, and you should. International guidelines on knee osteoarthritis name exercise as a core treatment, together with weight loss for people who carry extra weight.
- Weight is the biggest lever on knee load. In a gait study, every kilo lost meant about four kilos less force through the knee at each step.
- The most knee-friendly cardio: an exercise bike, water walking or a pool class, seated cardio, the elliptical, walking with poles and, for some people, a rowing machine.
- Use a simple pain rule. Pain up to about 5 out of 10 during exercise is acceptable if it settles back to your usual level within 24 hours.
- Avoid a few things at first, such as jumping and deep squats with weights, but there is no need to stop moving.
- Some signs need a doctor first: a hot, red, swollen knee, a knee that locks or gives way, or pain after a fall or twist.
Can you exercise with bad knees?
Yes. For most people with knee pain, the right kind of movement eases pain and makes daily life easier, while long rest makes the knee stiffer and the muscles around it weaker.
“Bad knees” can mean many things. In adults over 50 living with a higher weight, one of the most common causes is knee osteoarthritis: changes in the cartilage, bone and soft tissues of the joint that cause pain and stiffness, often worse after activity or at the end of the day.
Other causes include old ligament or meniscus injuries, pain around the kneecap and inflamed tendons. The advice on this page fits most long-term knee pain. If your pain is new, followed an injury, or comes with swelling or heat, read the section on when to see a doctor first.
Does exercise wear out your knees?
This is the most common fear, and the evidence does not support it. A systematic review of randomised trials that measured knee cartilage on MRI found that knee-loading exercise did not seem to harm cartilage in people with, or at risk of, knee osteoarthritis.
The authors called the quality of evidence low, so the honest summary is “no clear sign of harm”, not “proven to rebuild cartilage”. Pain during exercise and damage to the joint are not the same thing.
What exercise reliably changes is pain, strength and how well you move. Those are the things that decide whether you can climb stairs, get out of a car or walk to the shop.
Knee osteoarthritis and weight: why every kilo matters
Extra body weight raises the load on your knees with every step, and losing some of it is one of the most effective things you can do for knee pain. This is where food, walking and suitable exercise work together.
Load per step
Your knee does not carry just your body weight. When you walk, muscles pull across the joint and the forces add up to several times your weight.
Researchers in the United States measured knee forces during walking in older adults with overweight or obesity and knee osteoarthritis, before and after a weight-loss programme. For every kilo lost, peak compressive force on the knee dropped by roughly four kilos with each step.
Multiply that by a few thousand steps a day. Losing 5 kg means, in round numbers, around 20 kg less pressure on each knee per step, many thousands of times a day.
How much weight loss helps knee pain?
Even modest weight loss helps. A meta-analysis of randomised trials in people with knee osteoarthritis and overweight found that physical disability improved noticeably once weight loss passed about 5 % of body weight, ideally reached at a steady pace of about 0.25 % a week.
The best-known study is the IDEA trial. For 18 months, 454 adults aged 55 and over with knee osteoarthritis and overweight or obesity followed a diet programme, an exercise programme, or both.
| Group | Average weight loss | What changed most |
|---|---|---|
| Exercise only | 1.8 kg (2 %) | Smallest change in knee load and in an inflammation marker |
| Diet only | 8.9 kg (9.5 %) | Lower knee compressive force and lower levels of an inflammation marker |
| Diet plus exercise | 10.6 kg (11.4 %) | Least pain and best function of all three groups, and better physical quality of life than exercise only |
The message is clear: exercise alone did little for weight, and food did most of the work on knee load. Combining both gave the best result for how people felt and moved.
A later analysis of the two diet groups looked at how much weight people had lost. Benefits grew step by step: losing 10 to 20 % brought clear gains over smaller losses, and people who lost 20 % or more had about a quarter less pain again, with better function.
That does not mean you need a big number to feel a difference. It means every kilo you lose and keep off counts for your knees.
If the scale stops moving even though you are doing everything right, our page on not losing weight explains the usual reasons. Knees are only one of the joints and organs that benefit; our overview of health risks shows the others.
Exercise is a treatment for knee osteoarthritis
Exercise is not just allowed with knee osteoarthritis; it is one of the main treatments doctors and physiotherapists recommend. Two major international guidelines say so plainly.
- OARSI (Osteoarthritis Research Society International) lists structured land-based exercise, with or without dietary weight management, as a core treatment for knee osteoarthritis, together with education about the condition. Exercise in water is also recommended for the knee, though less firmly.
- The American College of Rheumatology and Arthritis Foundation make a strong recommendation for exercise, and a strong recommendation for weight loss in people with knee or hip osteoarthritis who have overweight or obesity. Tai chi and self-management programmes are also strongly recommended.
The largest summary of the research is a Cochrane review of 139 trials with nearly 12,500 participants. Compared with no treatment or usual care, exercise probably improved physical function by about 12 to 13 points on a 100-point scale, and may lower pain by a similar amount.
Those are modest average effects, and the review rated many trials as at risk of bias. In some comparisons exercise came with slightly more side effects, which is one more reason to build up gradually. It also costs nothing but time.
Which type of exercise is best for knee pain?
The type matters less than doing it regularly. The guidelines support strengthening, aerobic exercise, water exercise and mind-body activities such as tai chi, and the best one is the one you will still be doing in three months.
For weight loss and heart health, cardio deserves a place in your week. For knee stability, the muscles around the knee and hip need strength work too; our page on strength training for weight loss covers a routine you can do from a chair. This page focuses on the cardio side.
Cardio with bad knees: the most knee-friendly options
The best cardio for bad knees keeps your heart and lungs working while the knee moves smoothly, without landing, twisting or deep bending under your full weight. Cycling and water exercise top the list, but several other options work well.
In an international survey, 349 people living with knee osteoarthritis judged 30 types of aerobic exercise. Indoor cycling was rated knee-friendly by 82 % of them and water exercise classes by 70 %. Pole walking and brisk walking were also nominated often.
| Option | Knee load | How to start | Knee tips |
|---|---|---|---|
| Exercise bike (recumbent or upright) | Very low | 5 to 10 minutes at light resistance, 3 times a week | Seat high enough that your knee stays slightly bent at the bottom of the pedal stroke; low resistance, steady pace |
| Water walking or aqua class | Very low | 15 to 20 minutes walking in chest-deep water | Shallow-end steps and slow kicks; avoid hard push-offs from the wall if they hurt |
| Swimming | Very low | A few lengths with rests at each end | Front crawl and backstroke suit most knees; some people find the breaststroke kick uncomfortable |
| Elliptical cross-trainer | Low | 5 minutes, no incline, low resistance | Keep your heels down and knees in line with your toes; hold the handles for balance |
| Seated cardio | Very low | 5 to 10 minutes of seated marching and arm moves | Ideal on flare-up days; add an arm-crank or under-desk pedals if you have one |
| Walking with poles | Low to moderate | 10 minutes on flat ground | Poles add stability and work your arms; use them on slopes and uneven paths |
| Rowing machine | Low to moderate | 3 to 5 minutes at an easy stroke rate | Each stroke bends the knee deeply; skip it if a full bend hurts, try again later |
The minutes in this table are first-week starting points, not targets. Read the pain rule further down before you increase anything.
Cycling: the easiest place to start
A stationary bike lets the knee move through a large range with very little load, and you can stop the moment you need to. A meta-analysis of trials in people with knee osteoarthritis found that stationary cycling reduced pain compared with no exercise.
A recumbent bike, with a backrest and pedals in front of you, is often more comfortable in a heavier body and easier to get on and off. Check the maximum user weight before you buy or use one.
Setting up the bike well makes a real difference. A seat that is too low forces the knee into a deep bend under pressure, which is the most common reason cycling hurts. Raise the seat until your knee is only slightly bent when the pedal is at its lowest point.
Start with almost no resistance. Pedalling quickly against light resistance is kinder to sore knees than grinding slowly against a heavy setting.
Water walking and swimming
Water carries much of your body weight, so the knees bend and straighten without the usual load. A Cochrane review of 13 trials in people with knee or hip osteoarthritis found that exercise in water gave a small improvement in pain and daily function over about 12 weeks.
You do not need to swim. Walking forwards, backwards and sideways in chest-deep water, with your arms moving, raises your heart rate and strengthens the legs. Aqua classes add music and company.
If changing rooms or swimwear make you hesitate, you are far from alone. Many pools offer quieter sessions, and our page on weight stigma explains why that worry is so common and not your fault.
The elliptical cross-trainer
On an elliptical, your feet never leave the pedals, so there is no landing. The movement is close to walking, and the handles let your arms share the work.
Keep the stride smooth and the resistance low at first. Some machines have a high step-up height and a narrow platform, so hold on firmly while getting on and off.
Seated cardio
Seated cardio means rhythmic movement from a chair: marching, heel digs, arm punches and toe taps. It is the safest option on days when your knee is flaring up, and it keeps the habit going.
Our page on low impact cardio at home has a full 15-minute chair routine with easier and harder versions of every move.
Walking with poles
Walking is good for knees in most people with osteoarthritis, but it puts more load through the joint than cycling or water. Poles help many people walk further: they improve balance, bring the arms into the work and give you something to lean on downhill.
Set the poles so that your elbow is bent at about a right angle when you hold them with the tip on the ground. For a full beginner plan, see our guide to walking for weight loss.
Rowing
Rowing machines work the legs, back and arms together with no impact. The catch is that the knees fold up fully at the front of each stroke.
If a deep bend is comfortable for you, rowing is excellent cardio. If it hurts, leave it out for now and come back to it once your knees are stronger.
How much pain is OK when exercising with knee pain?
Some discomfort during exercise is normal and not a sign of damage. A simple way to judge it is the pain-monitoring model that physiotherapists use, which rates pain from 0 (none) to 10 (the worst you can imagine).
The protocol of a Danish exercise trial for knee osteoarthritis describes how physiotherapists apply it. Pain up to 2 out of 10 counted as safe and pain from 2 to 5 as acceptable. Pain above 5 was high risk, and an increase in pain at rest was accepted as long as it was back to normal within 24 hours.
| Pain during or after exercise (0 to 10) | What it means | What to do |
|---|---|---|
| 0 to 2 | Safe | Carry on, and build up slowly next week |
| 3 to 5, back to normal by the next day | Acceptable | Keep the same amount; do not add more yet |
| Above 5, or worse the next morning | Too much for now | Shorten or lighten the next session, or switch to a lower-load option |
The next-morning check is the most useful part. When you get up, compare your knee with how it usually feels. If it is stiffer or more painful than normal, your last session was a little too much, not a sign that exercise is wrong for you.
Sharp, stabbing pain, a knee that suddenly gives way, or new swelling are different. Stop and get advice before you continue.
What to do on a flare-up day
Flare-ups happen to everyone with osteoarthritis, often after an unusually busy day. Total rest usually makes the stiffness worse.
Switch to seated cardio or easy water walking, cut the time in half, and use a warm pack or a cold pack on the knee if that helps you. Return to your usual plan gradually over a few days.
Warm up your knees before cardio
Stiff knees need a few minutes to loosen before they take more load. A warm-up of five minutes is a practical habit that makes the first part of any session more comfortable.
- Seated knee bends: sit on a chair and slowly straighten and bend each knee ten times.
- Heel slides: slide one foot forwards along the floor and back, ten times per leg.
- Ankle pumps: point and flex both feet for 30 seconds to get the blood moving.
- Easy version of your cardio: pedal, walk or step at a very gentle pace for two to three minutes before you speed up.
Cool down in the same way: slow the pace for a few minutes, then stretch the front and back of the thighs gently. Morning stiffness that wears off within about half an hour is typical of osteoarthritis.
Our guide to warm-up and stretching has a complete routine for before and after exercise.
Shoes for bad knees
For walking, the elliptical and standing exercise, choose stable, supportive shoes. A randomised trial in 164 people with knee osteoarthritis compared flat, flexible shoes with stable, supportive shoes worn for six months.
The flexible shoes were not better. People in the supportive shoes had less pain while walking and fewer side effects.
In practice, look for a firm heel counter that does not fold when you squeeze it, a cushioned sole with some arch support, and a wide enough toe box. Replace walking shoes when the sole is worn down or the heel tilts.
For the bike and the pool, any comfortable trainers or pool shoes are fine. If one foot rolls inwards or you have foot pain as well, a physiotherapist or podiatrist can check whether insoles would help.
What to avoid with bad knees at first
A few movements put high or twisting loads on a sore knee, so leave them out in the early weeks. None of them is banned for life; many people add some back once their legs are stronger and their weight is lower.
- Jumping and running: skipping, jumping jacks, burpees and jogging multiply the landing load. Choose step-touches and marching instead.
- Deep squats and lunges under load: holding weights while bending the knees far is a lot for a painful joint. Partial sit-to-stands from a higher chair are a good alternative.
- Kneeling and full knee bends for long periods: gardening on your knees or sitting cross-legged can flare pain. Use a kneeling pad or stool.
- Twisting on a planted foot: fast turns in racket sports or dance classes. Turn with small steps.
- Steep downhill walking and high steps: many people find going down the hardest part. Use poles or handrails; on stairs, lead with your stronger leg going up and with the sore one going down.
- Heavy resistance on the bike or stair machine: keep the effort in your breathing, not in a grinding push through the knee.
A 6-week knee-friendly cardio plan
Talk to your doctor first, especially if your knee pain is severe, if you have heart or lung problems, or if you use insulin or tablets that can cause low blood sugar. This plan is general guidance, not personal medical advice.
Pick one or two main options from the table above, for example the bike plus water walking. Use the pain rule after every session, and repeat a week as often as you need.
Stop at once and get urgent medical help if you feel chest pain or pressure, severe breathlessness, faintness or a racing, irregular heartbeat during exercise.
| Week | Sessions per week | Minutes per session | Effort | Focus |
|---|---|---|---|---|
| 1 | 3 | 5 to 10 | Easy: you can talk in full sentences | Learn the set-up; check your knee the next morning |
| 2 | 3 | 10 to 12 | Easy to moderate | Same option, a little longer |
| 3 | 4 | 12 to 15 | Moderate: breathing faster, can still talk | Add a second option on one day |
| 4 | 4 | 15 to 20 | Moderate | Add the strength routine on two other days |
| 5 | 4 to 5 | 20 to 25 | Moderate | Try two short intervals of slightly faster pedalling or walking |
| 6 | 5 | 25 to 30 | Moderate | About 150 minutes a week, the general target for adults with chronic conditions |
Change only one thing per week: the number of sessions, the minutes or the effort. If your knee is worse the next morning, go back a week.
Want to see roughly what each session uses? Our calories burned calculator gives an estimate for cycling, swimming and walking. Use it out of curiosity, not to “earn” food.
How hard should it feel?
Moderate cardio means you breathe faster and feel warm, but you can still talk in short sentences. With bad knees, let your breathing set the pace and your knee set the limit.
If your heart and lungs could do more but your knee says no, switch to an option with less knee load, such as the bike or the pool, rather than pushing through.
Strong muscles take load off the knee
Cardio alone is not enough for bad knees. The thigh and hip muscles act as shock absorbers, and when they are weak, more of each step goes straight into the joint.
Two short strength sessions a week fit well alongside the plan above. Seated knee extensions, sit-to-stands from a raised chair and side leg raises work the right muscles without deep bending.
The full routine, with easier and harder versions of each move, is on our strength training page. If you prefer to follow along on screen, our free workout programme has seated and supported sessions at Level Start.
Food does the heavy lifting for your knees
In the IDEA trial, the groups that changed their eating lost far more weight than the group that only exercised, and the diet group also had clearly lower forces in the knee. Exercise works best alongside good food, not instead of it.
That does not mean a crash diet. A steady change that you can keep, built on vegetables, fruit, beans, whole grains and some protein at every meal, is kinder to your body and easier to keep up while you start moving more.
Our free eating plan is built on that kind of everyday food. Combined with knee-friendly cardio and walking at your own level, it is the approach we believe in.
When to see a doctor about knee pain
Most knee pain improves with self-help and a gradual return to activity. Some signs, however, need a check before you exercise on that knee, and a few need help the same day.
Book an appointment with your doctor or a physiotherapist if
- the pain is severe, or has not improved after a few weeks of self-help
- your knee is swollen
- you cannot bend or straighten your knee fully, or cannot put weight on it
- your knee locks, catches painfully or gives way
Painless clicking or creaking is common and nothing to worry about. Our doctor visit checklist helps you prepare questions for that appointment.
Get urgent medical help the same day if your knee is suddenly hot, red and swollen, especially with a fever. This can be a joint infection, which is more likely with diabetes, rheumatoid arthritis or a knee replacement.
Also seek urgent care after a fall, twist or blow if your knee swells quickly, looks deformed, locks in one position or cannot take any weight.
Also check with your doctor before starting if you
- have heart disease, chest pain on effort, or blood pressure that is not well controlled
- use insulin or tablets that can cause low blood sugar
- have had knee surgery or a joint injection recently
- have numb feet or foot ulcers from diabetes, which matters for pool and walking sessions
How Obesity Foundation helps you move with bad knees
We help people lose weight and get healthier with good food, suitable exercise and walking. Everything we offer is free, and it starts at the level your knees can handle today.
- Workout videos without jumping. Level Start uses a chair and supported standing moves, with an easier option for every exercise. Get the free workout videos.
- An eating plan for steady loss. Everyday meals that help take weight off your knees, with no crash diets or special products. Ask for your free eating plan.
- Your own Club account. Log your bike rides, pool sessions, walks and pain scores, and see your progress in private. Open your free Obesity Foundation Club account.
- Someone to talk it through. Unsure which cardio suits your knees or your health? Book a free video meeting (in English) with our team.
Your first session can be today: ten easy minutes on a bike, in the pool or on a chair, then a check of your knee tomorrow morning. That is how it starts.
Frequently asked questions
Is an elliptical good for bad knees?
For many people, yes. Your feet stay on the pedals, so there is no landing, and the handles let your arms share the work. Start with five minutes at low resistance and no incline, keep your knees in line with your toes, and hold on when getting on and off.
Is swimming or cycling better for knee osteoarthritis?
Both are good choices, and the best one is the one you enjoy and can reach easily. People with knee osteoarthritis rate indoor cycling and water exercise as the two most knee-friendly types of cardio. Research shows small to moderate pain relief for both, so many people combine a bike at home with a weekly pool session.
How much weight do I need to lose to help my knee pain?
Benefits start early. A meta-analysis found that physical function improved once people with knee osteoarthritis lost more than about 5 % of their body weight. In the IDEA trial, larger losses brought more relief, and each kilo lost reduces the force on the knee by about four kilos per step.
Should I rest my knee when it hurts?
Short rest after a flare-up is fine, but long rest usually makes knee pain and stiffness worse. Switch to a lower-load option such as seated cardio or water walking, shorten the session and build back up over a few days. If the knee is hot, red and swollen, get medical help the same day; if the pain followed a fall or twist, see a doctor first.
Can exercise make knee osteoarthritis worse?
There is no good evidence that suitable exercise speeds up joint damage. A review of trials that measured knee cartilage on MRI found that knee-loading exercise did not appear to harm cartilage in people with osteoarthritis, although the evidence was of low quality. Exercise can temporarily increase pain, which is why a pain rule and gradual build-up help.
Is it normal for my knee to ache the day after exercise?
A little more ache than usual is acceptable if it settles back to your normal level within 24 hours. If your knee is clearly worse the next morning, the session was too much for now: make the next one shorter or lighter. Sharp pain, new swelling or a knee that gives way needs a check.
Sources
- Messier SP et al. – Weight loss reduces knee-joint loads in overweight and obese older adults with knee osteoarthritis, Arthritis & Rheumatism (2005)
- Messier SP et al. – Effects of intensive diet and exercise on knee joint loads, inflammation, and clinical outcomes among overweight and obese adults with knee osteoarthritis: the IDEA randomized clinical trial, JAMA (2013)
- Messier SP et al. – Intentional weight loss in overweight and obese patients with knee osteoarthritis: is more better?, Arthritis Care & Research (2018)
- Christensen R et al. – Effect of weight reduction in obese patients diagnosed with knee osteoarthritis: a systematic review and meta-analysis, Annals of the Rheumatic Diseases (2007)
- Bannuru RR et al. – OARSI guidelines for the non-surgical management of knee, hip, and polyarticular osteoarthritis, Osteoarthritis and Cartilage (2019)
- Kolasinski SL et al. – 2019 American College of Rheumatology/Arthritis Foundation guideline for the management of osteoarthritis of the hand, hip, and knee, Arthritis Care & Research (2020)
- Lawford BJ et al. – Exercise for osteoarthritis of the knee, Cochrane Database of Systematic Reviews (2024)
- Bartels EM et al. – Aquatic exercise for the treatment of knee and hip osteoarthritis, Cochrane Database of Systematic Reviews (2016)
- Luan L et al. – Stationary cycling exercise for knee osteoarthritis: a systematic review and meta-analysis, Clinical Rehabilitation (2021)
- Espe Pedersen M et al. – A catalog of knee friendly aerobic exercises developed for patients with knee osteoarthritis: an international patient survey, ACR Open Rheumatology (2025)
- Bricca A et al. – Impact of exercise on articular cartilage in people at risk of, or with established, knee osteoarthritis: a systematic review of randomised controlled trials, British Journal of Sports Medicine (2019)
- Clausen B et al. – The effect on knee-joint load of instruction in analgesic use compared with neuromuscular exercise in patients with knee osteoarthritis: study protocol (EXERPHARMA trial), Trials (2014)
- Paterson KL et al. – The effect of flat flexible versus stable supportive shoes on knee osteoarthritis symptoms: a randomized trial, Annals of Internal Medicine (2021)
- Arthritis UK (Versus Arthritis) – Knee pain: symptoms, causes and treatment
- Margaretten ME et al. – Does this adult patient have septic arthritis?, JAMA (2007)