Water exercise is movement performed in a pool, usually standing in water somewhere between the waist and the shoulders, and it is not the same activity as swimming lengths. For anyone with joint pain or arthritis, that distinction matters more than any other on this page.
For a joint that hurts, water changes three things: how much of the body’s weight the joint carries, how much resistance each movement meets, and how warm the tissue around the joint stays while it moves. Those are mechanical facts about water, and they are the reason a pool comes up so often in writing about joint pain. What they are not is a plan for any particular person. Decisions about exercising with a joint condition belong with your own doctor or physiotherapist, who knows the joint and the person.
This guide covers what water does to load, resistance and temperature at a painful joint, the difference between aquatic therapy and a water aerobics class, what you can actually do in a pool, how different swimming strokes load the knee and the shoulder, when water exercise makes things worse, what the research examined, and how to find a pool in Toronto you can get into.
What does water change for a painful joint?
Water changes three things that matter to a painful joint: load, resistance and temperature. Everything else about exercising in a pool follows from one of those three. They are properties of water rather than effects of swimming, so they apply equally to someone doing lengths and to someone standing in the shallow end who has never swum in their life.
How much weight does water take off a knee or hip?
In chest-deep water, the legs carry about a third of the body’s weight. Arthritis Australia gives that figure directly. A knee that hurts after walking on pavement is loaded far less walking the same distance across a pool, because most of the weight is being held up by the water.
Chest depth is where that figure applies. Waist-deep water takes less weight off, and the effect shrinks further toward the shallow end. Chest depth for one adult is shoulder depth for a shorter one, which is why the depth of a pool’s shallow end is a more useful thing to know than the depth of the deep end.
Taking weight off is half of what water does. The other half is that water pushes back.
Why does every movement in water meet resistance?
Water resists movement in every direction, and the resistance rises with speed. On land, lifting a leg is resisted on the way up by gravity and assisted on the way down. In water, both directions meet resistance, and buoyancy rather than gravity decides which one is easier. Because moving faster is harder and slowing down instantly reduces the effort, water exercise is self-limiting: the intensity follows the person, with no equipment to adjust.
Does warm water change how a stiff joint feels?
Warm water changes how stiff tissue feels, which is why therapy pools are heated well above the temperature of a pool used for swimming lengths. A therapy pool is heated for slow upright movement. A lane pool is kept cooler because people swimming continuously generate heat and overheat quickly in warm water.
Alison Bonnyman, an aquatic physiotherapist in Toronto quoted by Arthritis Society Canada, describes 32 to 34 °C (90 to 92 °F) as a neutral, comfortable temperature for water therapy: warm enough not to lose body heat and cool enough not to overheat. Arthritis Australia puts hydrotherapy pools at around 34 °C and public swimming pools at about 28 °C, a gap of roughly six degrees between two buildings that both contain water.
Neither temperature is correct in general. An adult choosing between two facilities is often choosing between two temperatures without knowing it. Arthritis Society Canada also notes that a cooler pool is fine, as long as you can stay in long enough to get the benefit of the exercise.
What is the difference between aquatic therapy and water aerobics?
Aquatic therapy is a clinical treatment delivered by a qualified practitioner. Water aerobics is a fitness class. The two happen in water and share almost nothing else, and confusing them is why some people arrive at a pool expecting something it does not provide.
- Aquatic therapy (also called hydrotherapy or water therapy) is individualized treatment in water, prescribed and supervised by a qualified practitioner.
- Aquatic physiotherapy is aquatic therapy delivered by a physiotherapist, usually one to one, often in a heated pool.
- Water aerobics (aquafit) is a group fitness class of upright movement led by a fitness instructor, in which everyone follows the same routine.
- Recreational swimming is swimming lengths, with or without instruction, in an ordinary pool.
| Activity | Who delivers it | Where it happens | What it requires |
| Aquatic therapy / hydrotherapy | A qualified practitioner, usually a physiotherapist | Hospitals, rehabilitation centres, some physiotherapy clinics and leisure centres with a heated therapy pool | Usually a referral and an individual assessment |
| Water aerobics (aquafit) | A fitness instructor | Community and public pools | Nothing clinical; confidence to let go of the wall and move around |
| Recreational swimming | The swimmer, or a swimming coach | Any pool with lane space | A stroke, and comfort in the water |
| Water walking | Nobody; you do it on your own | Any pool with a shallow end | Nothing at all |
The facilities differ too. Arthritis Australia notes that hydrotherapy pools generally have a ramp, a hoist or gently sloping steps rather than a ladder, because getting in and out is part of what they are designed for. In Toronto, the Arthritis Aquatic Program at Sunnybrook’s St. John’s Rehab is an example of where warm-water arthritis exercise is actually delivered: an eight-week program in a pool kept at 33 to 35 °C, led by trained instructors, and it requires a doctor’s referral.
That distinction decides what any provider can offer, including this one.
What Rocket Swim Club offers, and what it does not
Rocket Swim Club teaches swimming. It does not provide aquatic therapy, hydrotherapy, aquatic physiotherapy or any clinical aquatic program, and nothing in its lessons is treatment. Our coaches are certified to teach swimming and to supervise water safely. That does not qualify them to assess a joint.
An adult who has been referred for aquatic therapy needs the pool their clinician sends them to. An adult who wants to swim, or to be comfortable enough in water to use a shallow end confidently, is in the right place here. Those are different needs, and they are sometimes the same person at different times.
What can you actually do in the water?
Three kinds of movement account for nearly everything people do in a pool for a painful or stiff joint:
- Walking in the shallow end, upright, at whatever pace suits the day
- Moving one joint at a time while standing supported at the wall
- Swimming lengths, horizontal and continuous, using a stroke
The first two happen in water you can stand up in. Only the third requires swimming ability. How much of any of them suits a particular person is a question for that person’s clinician; the descriptions below are of the activities, not of a session.
Water walking
Water walking is walking in chest-deep water: forwards, then backwards, then sideways. There is no equipment, no instruction and no swimming involved, and it is available to an adult who cannot swim at all.
Arthritis Society Canada reports that walking, jogging or running in water offers the same benefits as those activities on land, without the impact on the joints. It also makes a more specific point most people never think of: if your hips or knees are sore when walking or doing stairs, those are the movements worth practising in the pool. Many pools have steps into the shallow end, and walking up and down them in water takes part of the body’s weight off, more the deeper the step.
The three directions matter because they load differently. Walking forwards uses the pattern the legs already know. Walking backwards and sideways asks for patterns that rarely come up on land, in water slow enough to correct a mistake in.
Balance is the other difference. As Bonnyman puts it, if you fall in the water, you are only going to get your hair wet. Water slows a loss of balance into something you can recover from standing up, which is why some people who have stopped walking outdoors on Toronto ice are still walking in a pool in February.
Range of motion work at the pool edge
Range of motion is how far a joint travels between its limits, and working on it in water means moving one joint through that range while the water carries most of the body’s weight. It happens standing at the wall, holding the edge, which takes most of the balance demand away and leaves the joint as the main thing being asked to work.
Which movements, through what range and how often is exactly the question an aquatic physiotherapist answers for an individual. Arthritis Australia makes the point bluntly: exercises you see other people doing may not be right for you.
Swimming lengths
Swimming lengths is continuous horizontal movement using a stroke, and it is the only one of these three that requires swimming ability. It is also the one that delivers joint-friendly cardio in the ordinary sense: a heart rate raised and held there for a stretch of time, with no landings and no jolts.
The trade-off is pacing. A length is harder to stop in the middle of than a walk across the shallow end, and the wall is a fixed distance away. A swimmer who starts feeling fine and does not feel fine at the 15-metre mark has fewer options than a walker who simply stops. For someone whose joints vary day to day, that is a real difference.
Which swimming stroke is best for bad knees and shoulders?
Strokes load joints differently, and the difference comes almost entirely from the kick and from how the arm travels back to the front. This is the part that gets flattened into “swimming is low impact” on most pages about joint pain.
Three terms make the table readable. A flutter kick is the alternating up-and-down kick used in front crawl and backstroke, driven mostly from the hip with a fairly straight leg. A whip kick is the simultaneous kick used in breaststroke, in which the knees bend, the feet turn outward and the legs sweep together. Arm recovery is the part of the stroke where the arm travels back to the front of the body, through the air in some strokes and under the water in others.
| Stroke | Knee and hip (kick) | Shoulder (arms) | In short |
| Front crawl (freestyle) | Flutter kick: fairly straight leg, driven from the hip, little knee bend | Full overhead rotation on every stroke, arm recovering above the water | The shoulder works hard; the knee comparatively little |
| Backstroke | Flutter kick, same pattern, on the back | Full overhead rotation in the opposite direction | Similar shoulder demand to front crawl, with no need to turn the head to breathe |
| Breaststroke | Whip kick: knees bend, legs rotate outward and sweep together | Arms stay in front of the body and recover under or near the surface | Asks the knee and hip for a rotational pattern they do nowhere else |
| Elementary backstroke | Whip kick, on the back | Arms travel up the sides of the body, not overhead | The lowest shoulder demand of the four |
The pattern is that the two strokes easiest on the shoulder are the two that ask most of the knee, and the other way around. A knee and a shoulder that both hurt narrow the options from two directions at once.
What the table does not do is pick a stroke. Which stroke suits a joint depends on which joint, what is wrong with it and what movement provokes it. That is a question to ask a clinician first, then bring to a coach, who can adapt a stroke once someone has told them what to work around.
Can water exercise make joint pain worse?
Yes. Water exercise can make joint pain worse, usually in one of four predictable ways.
- Pushing through pain. Water makes effort easy to underestimate, because the resistance is smooth and the load is low. A movement that provokes a joint still provokes it at a third of body weight.
- A pool colder than the activity suits. Slow upright movement generates very little heat. In a lane pool kept for continuous swimming, someone moving slowly gets cold.
- A stroke that loads an already painful joint. The table above exists for this reason. A breaststroke kick is a specific demand on the knee whether or not that knee is having a good week.
- Doing much more on a good day. This is the most common one. A joint that feels better than usual invites a longer, harder session, and the consequence arrives the next morning rather than in the pool.
Pain that climbs during a session and swelling that shows up the next day are both signals. What they mean is a question for your clinician. What is clear without any clinical judgement is that neither is a reason to push harder.
What the research covers, and what it does not
Most research on water exercise and joint pain examined supervised programs of upright aquatic exercise, not people swimming lengths. That changes what the evidence can be used to say.
A Cochrane review led by Bartels and colleagues, published in 2016, pooled 13 trials covering 1,190 people with knee or hip osteoarthritis. It found moderate-quality evidence of small, short-term, clinically relevant effects on patient-reported pain, disability and quality of life. Three of those words carry most of the weight and are usually dropped when the review is quoted: small, short-term, patient-reported. What was studied was a protocol delivered to a trial population, not an outcome anyone can be promised.
The wider research picture, including the reviews on fibromyalgia and chronic low back pain, is covered in our guide to swimming for health conditions.
Is swimming better than walking for arthritis?
Neither is better in general, because they do different things. Walking loads the joint and the skeleton, which is useful for bone and hard on a painful knee. Swimming removes nearly all of that load, which is easier on the knee and does little for bone. Walking needs no skill. Swimming needs a stroke.
Water walking sits between the two, which is why it appears so often in the research: it is walking, in the ordinary pattern, with most of the weight removed and no stroke required.
How long should you swim to relieve joint pain?
That depends on the person, and it is a question for your doctor or physiotherapist rather than a web page. The honest answer has to account for the condition, its current state, what else you do in a week and how your joints respond afterward.
What exists instead is general physical activity guidance written for adults rather than for a condition. The Canadian 24-Hour Movement Guidelines, published in 2020 by the Canadian Society for Exercise Physiology, recommend that adults accumulate at least 150 minutes a week of moderate to vigorous aerobic activity, plus muscle-strengthening activity at least twice a week. The guidelines for adults 65 and older use the same figures and add activities that challenge balance. Swimming and water exercise count toward the aerobic total when done at moderate to vigorous intensity.
That is a figure for a week of activity, not a dose for a joint. How any individual should spread it out, or whether they should, is the part that needs a clinician.
How soon after joint replacement surgery can you swim?
Your surgeon decides, and there is no useful general number.
The deciding factor is the wound. Immersing an incision that has not fully closed carries a real infection risk, and in a replaced joint an infection is a serious complication. The American Academy of Orthopaedic Surgeons, in its OrthoInfo guidance on activity after total knee replacement, describes swimming as an excellent low-impact activity that can begin once the wound is sufficiently healed.
Beyond the wound, the procedure, the implant and the individual’s healing all matter. Published timelines disagree with each other noticeably, which is the clearest argument for taking the answer from the surgeon who did the operation rather than from any page, including this one.
What water does not do for joints
Water removes load, and removing load has a cost. Swimming and water exercise are not weight-bearing, so they do not load the skeleton the way walking, stair climbing or lifting does, and bone responds to the forces that pass through it. A person who needs that kind of loading gets it on land. The wider account of what swimming does and does not do physically is on our benefits of swimming page.
Water exercise is also not a treatment for arthritis or any other condition, and it does not replace the strength work that land training provides. These are limits on the activity rather than faults in it, and most physical activity guidance treats swimming as one part of a week rather than the whole of it.
Where to swim in Toronto with a painful joint
Rocket Swim Club runs programs at pools in Toronto’s west end: Western Technical-Commercial School, Swansea Community Recreation Centre, Runnymede Collegiate Institute and York Memorial Collegiate Institute, serving High Park, Swansea, Runnymede and Eglinton West. Sessions run through the week, including evenings, and continue through holidays and summer. Times vary by group and term and are confirmed through the club’s registration system, so the quickest route to a current answer is to contact the Rocket Swim team.
Toronto gives the question a seasonal edge. Ontario winters are long, and for anyone whose joints feel worse in the cold, outdoor movement stops being an option for months at a time. An indoor pool is the same temperature in January as in July, which for some people is the only part of their week that does not change with the weather.
An adult who cannot yet swim is not excluded from any of this. Water walking, shallow-water movement and range of motion work at the wall all happen in water you can stand up in. For anyone who wants the stroke as well, our adult learn-to-swim lessons in Toronto start from no ability at all, beginning with getting in and out of the water comfortably, breath control, floating and getting back to standing.
What to ask a pool before a first session
Five questions decide whether a pool suits someone with a painful joint, and none of them is answered in a program description:
- What temperature is the water kept at? Several degrees separate a therapy pool from a lane pool, and it changes which activity is comfortable.
- How deep is the shallow end? This decides how much weight the joints carry, and chest depth is a different number for different people.
- How do people get in and out? Steps with a handrail, a ladder, a graded ramp and a lift are four different answers.
- How far is the change room from the water, and is there anywhere to sit? For some people this matters more than the pool.
- How busy is it at that hour? Moving slowly in a lane shared with four continuous swimmers is a different session from the same movement off-peak.
A fuller version of this list, with the reasoning behind each question, is in our swimming for health conditions guide. Rocket Swim Club answers all five for its own Toronto pools on request.
Getting into and out of the water
Entry is the part nobody writes about and the part that stops people. A pool that is ideal once you are in it is useless if the route from the change room to the water is forty metres of wet tile with nothing to hold.
Arthritis Society Canada is direct about the practical side. If you use a walker or a cane on land, you can bring it onto the pool deck, and public pools should have proper railings and hand holds. Swimwear is its own obstacle: a tank-style suit is easier to get on and off than a racerback, adaptive swimwear with a front zipper exists, and some pools allow a nylon t-shirt and shorts instead of a swimsuit.
Common questions about water exercise and joint pain
Do you need to be able to swim to do water exercise?
No. Water walking, standing movement and range of motion work at the wall all take place where you can stand, and an adult who cannot swim a stroke can do all of them. Swimming lengths is the only part that requires swimming ability, and it is a learnable skill at any age.
Is swimming good for arthritis?
Water exercise is widely recommended by arthritis organizations, but most of the evidence is for upright aquatic exercise rather than swimming lengths. The Cochrane review above found small, short-term benefits for knee and hip osteoarthritis. Whether swimming lengths suits a particular joint, and which strokes to avoid, is a question for your doctor or physiotherapist.
Is water aerobics only for older adults?
No. Classes are often aimed at older adults, which is where the assumption comes from, but joint pain arrives at every age. A 38-year-old rebuilding after a knee injury is in the same situation as a 70-year-old with a stiff hip: land exercise provokes something, and water does not provoke it in the same way.
Is a cold pool bad for stiff joints?
Not inherently. Arthritis Society Canada notes that a cooler pool is fine as long as you can stay in long enough to get the benefit of the exercise, and that short periods in a plunge pool do not affect the joints. The practical issue is slow movement: someone moving gently generates very little heat and gets cold before they have done much.
Can you do water exercise during a flare?
That is a question for a clinician rather than a swimming club, and the answer differs by condition and by person. What is worth saying is that the access questions above matter most on exactly those days. Someone who already knows where the handrail is and when the pool is quiet has more options on a bad day than someone who does not. Persistent pain and wellbeing are connected, which our swimming and mental health guide covers separately.
Does water exercise replace strength training on land?
No. Water provides resistance without impact, which is useful, but no weight-bearing load, which is the part bone responds to. Land-based strength work does something water cannot, and activity guidelines treat the two as separate requirements rather than alternatives.