Pilates for knock knees: what the shape is and isn't, the hips and the feet, what Pilates can and can't change, what the evidence shows, and a 25-minute class

Pilates won't reshape your legs

We found no trial of Pilates, or any exercise, for the shape of knock knees. The one adult trial that X-rayed the legs after exercise was in bow legs, and the angles changed by about a degree.

Sources 1, 2

Children's knock knees are normal

Most children are knock-kneed at 3 to 4, and their legs usually settle by about 7. Exercises, braces and special shoes are rarely helpful. See a GP if one leg is affected, they're getting worse, or they last past about 7.

Sources 3, 4, 5

Knees that cave in are trainable

Knees that move inward during squats and landings improved with technique practice, and with strength work combined with knee position control. Strength training on its own made people stronger without changing how they landed.

Sources 6, 7

The Pilates trials are small

In 36 young adults whose knees caved in, 6 weeks of supervised Pilates improved the knee's angle in a jump test, but it's unclear whether Pilates beat the no-exercise group, and the trial was registered after it ran.

Source 8

Caving knees don't predict injury for one person

Across 9 cohorts, no measure of the knee moving inward predicted injury to the anterior cruciate ligament (ACL), a key ligament inside the knee. Prevention warm-ups still cut ACL injuries by about half.

Sources 9, 10, 11

Know the warning signs

A child's knock knees that affect one leg, get worse, hurt, cause a limp or last past about 7 need a GP. In adults, a knee that locks or gives way needs checking. The full lists are below.

Sources 5, 4

Two different thingsEmerging evidence

Knock knees (genu valgum) are when the knees touch but the ankles stay apart. Adult knees normally sit in a slight knock-knee. "Knock knees" can mean the shape of the legs when you stand still, which the bones set, or knees that move inward during a squat, step-down or landing (dynamic knee valgus), often with the foot rolling in. The first doesn't change with exercise; the second can.

Sources 5, 6

Filming yourself is a guide, not a measurementEmerging evidence

The knee angle on a phone video from the front is repeatable, but across 16 studies it matched lab (3D) measures moderately in landings and poorly in single-leg squats. Use a video to practise, not to diagnose.

Source 12

Women's kneesEmerging evidence

On average, women have a slightly more knock-kneed alignment than men, with plenty of overlap.

Sources 13, 14

Knock knees and arthritisEmerging evidence

In people who already have knee arthritis, a knock-kneed alignment raised the odds of the outer part of the knee getting worse about 5-fold, in studies of 237 and 950 people. More than 3 degrees of knock-knee went with new arthritis in the outer knee in one analysis but not in another. Exercise is still the core treatment for knee arthritis: see our Pilates for knee pain guide.

Sources 15, 16, 17

What Pilates asks of the knees

The Pilates stance (heels together, toes turned out) and reformer footwork in that "V" bring the knees together, so with knock knees they may touch before the heels do. Side-lying leg work trains the side hips; bridges, footwork and standing work let you practise keeping the knee over the foot.

Source 18

How children's legs changeStrong evidence

In 196 children, legs were most bowed at 6 months, straight by about 18 months and most knock-kneed at about 4 (an average of 8 degrees); up to 12 degrees, and a gap of up to 8 cm between the ankles, was normal from 2 to 11. Other groups of children peak a little later or lower, and in one X-ray study the angle kept falling until about 10. Children's orthopaedic services say they usually settle by about 7.

Sources 3, 19, 20, 21, 5

No special exercise is neededStrong evidence

The American Academy of Pediatrics says bracing, corrective shoes and exercise "are rarely helpful" for children's knock knees. Active play is what children need, and Pilates is fine as play.

Source 4

WeightEmerging evidence

Across 73 studies, mostly snapshots, children with overweight or obesity were more likely to have knock knees, and most of 66 children whose knock knees persisted past 7 had obesity. In 47,588 teenagers, about 6% had knock knees, girls more often than boys.

Sources 22, 23, 24

When treatment is neededEmerging evidence

Knock knees on one side, or that are painful, getting worse or severe, can have a cause such as rickets, a growth plate injury, infection or a bone disorder. Severe knock knees that don't settle can be corrected with a small operation that guides growth, which relies on growth being left: our knock knees guide covers it.

Sources 25, 26, 27, 28, 29

No trial for the shape of knock kneesStrong evidence

Our searches of PubMed, Europe PMC and ClinicalTrials.gov in October 2026 found no trial of Pilates or corrective exercise for the shape of knock knees in children or adults, only for knees that cave in. The one adult trial that X-rayed the legs after exercise was in 40 women with bow legs: after 12 weeks, the angles changed by about a degree, too little to call reshaping. In children, correction comes from growth.

Sources 1, 2, 4

Knees that cave in: what changes themEmerging evidence

A 2025 review of 35 studies in 1,095 healthy adults found technique training and core strengthening reduced knee valgus in people whose knees were in line to start with, and that combining strengthening with knee position control may reduce it in people with more valgus. In a review of 10 studies, 7 programmes of 2 to 10 weeks for the muscles that cross the knee reduced it. In 66 women, 9 weeks of strength training alone didn't change how they landed. Hip strength related weakly, if at all, to knees caving in, across 33 and 22 studies. Injury prevention programmes reduced the inward load on the knee in landings (28 studies).

Sources 6, 30, 7, 31, 32, 33

The Pilates trialsMixed evidence

Three small studies, all of knees that cave in, none of the shape of the legs:

• In 36 young adults whose knees caved in, randomised to Pilates, neuromuscular exercise or no exercise, 18 supervised Pilates sessions over 6 weeks improved the knee's angle in a drop jump, and both exercise groups improved in a single-leg squat. The summary gives p values, not effect sizes, and it's unclear whether Pilates beat the no-exercise group; the trial was registered after it ran.
• In 34 novice runners, 12 weeks of home mat Pilates didn't significantly change how far the knees caved in while running. It too was registered after it ran.
• In 30 teenage female volleyball players, matched in pairs and then randomised, 8 weeks of reformer and Cadillac Pilates (3 sessions of 50 minutes a week) reduced landing errors against no training. Injuries weren't counted.

Sources 8, 34, 35

Caving knees and injuryMixed evidence

In 205 female athletes, the 9 who later tore an ACL had landed with their knees moving further inward. But in 710 elite players, a drop jump test couldn't predict ACL injuries, and across 9 prospective studies "knee abduction kinematics and kinetics during weight-bearing activities may not be risk factors for future ACL injury" (knee abduction is the knee moving inward). Neither the Q angle (how the thigh and shin line up at the kneecap) nor weak hips predicted kneecap pain in 18 cohorts of 4,818 people, though one review of landing and overuse injuries found preliminary evidence that more inward knee movement on landing is a risk factor for it.

Sources 36, 9, 10, 37, 38

Prevention warm-ups workStrong evidence

Across 8 meta-analyses, injury prevention warm-ups halved ACL injuries overall and cut non-contact ACL injuries in women and girls by about two-thirds. A 2026 position statement puts it at about 60% in teenage girls playing football, basketball or handball, with programmes of 10 to 30 minutes, 2 to 3 times a week, but says direct evidence that training aimed at caving knees itself cuts injuries "remains limited".

Sources 11, 39

Kneecap pain and core trainingEmerging evidence

Neuromuscular training eased kneecap pain and improved function across 17 trials (871 people, moderate certainty) without consistently changing how the legs moved. Core training may improve how much the knee bends in landings, at low certainty.

Sources 40, 41

Knees that touch in the Pilates "V"

If your knees touch before your heels do, stand or lie with your feet hip-width and parallel, or let your heels sit apart (our suggestion). For reformer footwork, classical teachers cue: "Avoid hyperextending knees, separate feet hip distance for knees that overlap".

Source 18

Reformer footwork and the jumpboard

Keep your knees over your middle toes. If they drift in, slow the carriage and use a lighter spring, and land jumpboard work softly with your knees in line (our suggestion).

Kneeling and side-sitting

The moves' own lines. Kneeling side kick: "Avoid it with knee problems, and pad the kneeling knee." Mermaid: "If side-sitting bothers your knees or hips, sit cross-legged, on a block or on a chair."

Knees that bend back

If your knees bend backwards when they're straight, keep them soft in standing work rather than locked (our suggestion).

Kneecap pain

The step-down's own caution: "Lowering off a step loads the kneecap more than stepping up the same step, and more the higher the step: with pain at the front of the knee, start with low step-ups and add step-downs from a low step once those are comfortable." Our Pilates for knee pain guide has the kneeling swaps.

Children: see a GP if

Most knock knees and bow legs in young children are normal. Get them checked if:

• Only one leg is affected, or one leg looks different from the other.
• The knock knees or bowing are getting worse, or look severe.
• Knock knees continue after about age 7, or get worse in a child under 2 or over 7, or bow legs get worse after age 2.
• The gap between the ankles is more than 8 cm when your child stands with the knees together.
• Your child has knee pain, a limp or difficulty walking.
• Your child is unusually short for their age.
• You have any other worry about how your child stands or walks.

Sources 5, 4, 27

A child who suddenly can't bear weight

Call 999 or go to A&E if a child gets sudden pain in the hip, knee or thigh, can't put any weight on a leg, has a leg that has changed shape or points at an odd angle, feels unwell with a high temperature or hot, cold and shivery, has severe pain low in the tummy as well, or is getting worse.

For a limp with no obvious cause, see a GP.

Source 42

Rickets

Rickets, from a lack of vitamin D, can cause knock knees as well as bow legs.

There are other signs of rickets: swollen, painful wrists, aching bones, weak muscles or teeth coming through late.

Source 43

Adults: get help now

• Get advice from NHS 111 now: the knee locks, gives way or clicks painfully. Painless clicking is normal.
• Get advice from NHS 111 now: after a twist, your knee won't go fully straight, or something blocks the last part of straightening, even if you can still walk on it. A torn piece of meniscus caught in the joint can do this, and it needs checking promptly.
• Get advice from NHS 111 now: a hot, red or swollen knee with sudden severe pain, a very high temperature, or feeling hot, cold or shivery. This can be a joint infection.
• Get advice from NHS 111 now: you cannot move the knee or put any weight on it, or it is very painful, badly swollen or has changed shape.
• You hurt your knee and cannot take 4 steps, or you are 55 or over and have injured it: get it checked the same day for a broken bone.
• Same day (urgent GP appointment or NHS 111): throbbing pain in one leg (rarely both), usually the calf or thigh; swelling in one leg (rarely both); red, blue or darkened skin; or swollen veins; or sudden worse pain and swelling around a lump at the back of the knee (a possible clot or a burst Baker's cyst).

Source 44

Adults: see a GP or physiotherapist

• Knee pain that has not improved within a few weeks of looking after it at home. Many areas offer NHS physiotherapy without a GP referral.
• Numbness, tingling or weakness that travels down the leg from the back. That points to a nerve (sciatica) rather than the knee.
• A leg shape that is changing, especially on one side, is worth showing a GP (our editorial advice).

Source 44

During Pilates

Sharp, catching or giving-way pain, or new swelling, is a reason to stop and get it checked.

Rate your knee pain from 0 to 10 during and after exercise. In the pain-monitoring model used in knee trials, 0 to 2 counts as safe, up to 5 as acceptable and above 5 as too much. Aim for 0 to 3 most of the time.

Chest pain or fainting while exercising: call 999

Call 999 if:

• You get sudden pain or discomfort in your chest that doesn't go away; it can feel like squeezing or pressure, burning or indigestion.
• The pain spreads to your left or right arm, or your neck, jaw, stomach or back.
• You have chest pain and feel sweaty, sick, light-headed or short of breath.
• Someone faints while exercising, can't be woken within 1 minute, or has chest pain or a pounding, fluttering or irregular heartbeat.

Sources 45, 46

Unusual breathlessness

Call 999 or go to A&E (accident and emergency) straight away for severe difficulty breathing (gasping, choking or not able to get words out), a chest that feels tight or heavy, pain that spreads to your arms, back, neck and jaw, lips or skin turning very pale, blue or grey, or sudden confusion. If you're more short of breath than usual, or your heart is racing, fluttering or skipping beats, contact NHS 111.

Stop the session if

You feel any pain or become unwell, as the NHS advises for its Pilates videos, and especially for chest pain or pressure, unusual breathlessness, dizziness or fainting. If you have a health problem, an injury or any symptoms, get advice from a healthcare professional, such as a GP, before you start.

Source 47

Before you start

The NHS advises getting advice from a healthcare professional first if you have a health problem, an injury or symptoms, or have recently had a heart attack or an operation.

Source 47

"Exercise, or Pilates, can straighten knock knees"Strong evidence

No trial shows exercise changes the shape of the legs. In children, correction comes from growth; in adults, the only X-ray trial (in bow legs) changed the angles by about a degree.

Sources 1, 2, 4

"Knees caving in on a squat means you have knock knees"Emerging evidence

Knees that cave in are a movement, not a bone shape: people with straight legs can cave in too, and it responds to technique and strength training.

Source 6

"Strong glutes stop your knees caving in"Emerging evidence

Hip strength relates weakly at most to knees caving in, and strength training alone didn't change how women landed. Practising the movement matters.

Sources 31, 32, 7, 6

"Knees that cave in mean you'll tear your ACL"Mixed evidence

A landing test couldn't predict ACL injuries in 710 elite players, and across 9 cohorts no measure of the knee moving inward did. Prevention warm-ups lower the risk across groups of athletes.

Sources 9, 10, 11

"Children's knock knees need exercises, special shoes or braces"Strong evidence

They are normal at 3 to 4 and usually settle by about 7, and bracing, corrective shoes and exercise are rarely helpful.

Sources 3, 5, 4

"A strong core prevents knee injuries"Mixed evidence

Core training may improve knee bend in landings at low certainty, and trunk-focused programmes didn't reduce knees caving in, in one review. The ACL prevention programmes that work mix landing, strength, balance and agility.

Sources 41, 30, 39

"Untreated knock knees lead to arthritis"Mixed evidence

In people who already had knee arthritis, a knock-kneed alignment sped up wear on the outer knee. Whether it causes new arthritis is unclear: one analysis found a link and another didn't.

Sources 15, 16, 17

"Knock knees cause knee pain"Emerging evidence

The Q angle didn't predict kneecap pain. A knock-kneed alignment matters most for how the outer knee wears in people who already have arthritis.

Sources 37, 15