Usually an overuse ache around the kneecap or a tendonEmerging evidence
In young Irish dancers seen at one clinic, "Overuse injuries accounted for 90.7% of knee injuries", and kneecap tracking problems made up 53.5% of them. Kneecap pain (patellofemoral pain) is a dull ache around or behind the kneecap, worse in pliés, jumps, on stairs, squatting and after sitting with the knees bent: the American Academy of Orthopaedic Surgeons (AAOS) describes "a dull, aching pain in the front of the knee". In 1,359 young female dancers aged 8 to 20, 23.6% had kneecap pain when screened, more often the older and more flexible dancers, and in hip hop dancers at a London clinic, women mostly had kneecap pain (60% of their knee injuries). It can come and go: in 67 young dancers followed for 2 years, none had recovered by the first follow-up, but 40.5% of those who still had it then had recovered by the second.
Pain at one point just below the kneecap that builds with jumps and landings is usually the patellar tendon (jumper's knee); just above it, the quadriceps tendon. Dancers with patellar tendon pain landed leaps with "greater vertical and braking impulses than healthy dancers" in a small lab study, which can't show which came first. Tendon changes on a scan are often painless: in 57 young ballet students scanned over 2 years, "Only 2 of 5 participants who developed pathology reported pain associated with their tendon".
Sources 1, 2, 3, 4, 5, 6, 7
Not a high-risk activity per hour, and the knee's share depends on the styleEmerging evidence
Injury rates were under 5 per 1,000 hours of dance at every level, and social salsa dancers had about 1 injury per 1,000 hours for women and 0.5 for men. In female hip hop dancers, aches were common but injuries that stopped dancing were rare (0.72 per 1,000 hours). The knee was about 1 in 10 injuries in ballet and 1 in 7 in contemporary dance students, but the top site in hip hop and street dance: 36% of injuries at a London hip hop clinic, and 47% in youth street dancers, much of it in breaking.
Sources 8, 9, 10, 11, 12, 4, 13
Landings, and tirednessEmerging evidence
Most knee loading in dance comes in landings. Irish dancers "must land from difficult moves without letting their knees bend or heels touch the ground, causing large forces to be absorbed by the body", and ballet dancers with kneecap pain jumped higher and landed with more force and kneecap stress. Tiredness matters: in 40 dancers and 40 team sport athletes, "all groups landed with worse alignment after being fatigued", and anterior cruciate ligament (ACL) tears in elite dancers "happened most often late in the day and season, suggesting an effect of fatigue".
Sources 14, 15, 16, 17
Turns, deep pliés and kneelingEmerging evidence
No study has measured knee injury from turns; the one lab study of pirouettes had 5 dancers. Twisting on a foot that grips the floor (a sticky floor, street shoes or rubber soles) is the classic way to strain a knee in any sport (our reading, as our twisting guide explains), and a kneecap can slip out of place on a turn.
In 20 professional ballet dancers, the knee rotated inwards by about 30 degrees while bent to about 135 degrees at the bottom of a full grand plié, which the authors suggest might stress the menisci (the knee's cartilage pads); that is an idea, not an injury finding. In strength training studies, stress behind the kneecap peaks around a right-angle bend, and "Contrary to commonly voiced concern, deep squats do not contribute increased risk of injury to passive tissues" when they are built up gradually.
Kneeling floor work in contemporary, hip hop and breaking presses on the small fluid sacs (bursae) in front of the kneecap. No dance study measures it, but ultrasound found thickened bursae in 49% of carpet and floor layers against 7% of house painters, and in cadaver knees, "Pressures also increased significantly moving from double to single stance kneeling". The NHS advises padding when kneeling puts a lot of pressure on a joint, and regular breaks.
Sources 18, 19, 20, 21, 22, 23
Forcing turnout from the kneeEmerging evidence
Turnout should come from the hips. When dancers turn out further than their hips allow, the extra twist comes from lower down: "Dancers commonly rotate at the tibiofemoral joint and/or the talocrural joint to increase external rotation of the entire lower body, placing increased stress on these joints" (the knee and the ankle). In 30 college ballet dancers, those with a past low back or leg injury had forced their turnout by 25 degrees on average, against 5 degrees in those without; across two pooled studies, "Injured dancers had a significantly higher compensated turnout range of motion than non-injured dancers"; and in 47 contemporary students followed for 10 months, each 1% more forced turnout went with 9% higher odds of two or more injuries. A 2026 review of 4 studies (431 ballet dancers) concludes "Increased CTO may be associated with a higher risk of lower extremity injuries in ballet dancers" (CTO is compensated, or forced, turnout).
How much this matters for the knee itself is less certain. The injury studies are small and count leg and back injuries together, and none separates the knee, so the knee link rests on how forced turnout works and two small studies: in 24 ballet dancers, those with a tight band down the outer thigh used more twist at the knee in demi-plié and had more kneecap pain, and in a Dutch ballet company, ACL tears happened landing in turnout with the knee falling inward.
Sources 24, 25, 26, 27, 28, 29, 30
Dancing in heelsEmerging evidence
No study has measured the knee while dancing in heels; the evidence is small walking studies of people who weren't dancing. In them, heels raised the load on the front and inner knee: stress behind the kneecap rose with heel height, from 1.9 to 3.6 megapascals (a unit of pressure) between a 1.27 cm and a 9.53 cm heel; knee forces were "average 23% greater" in high heels than barefoot; "Even shoes with moderately high heels (1.5 in) significantly increase knee torques"; and a meta-analysis of 14 studies found higher heels raised the knee's bending and inward-tilting loads.
Dancing in heels adds bent-knee work, quick changes of direction and hours on your feet, so a sore kneecap after a night in heels fits (our reading). One 60-minute stiletto class raised markers of muscle damage in 16 young women.
Sources 31, 32, 33, 34, 35
Long nights, more hours, floors and shoesEmerging evidence
Aches build with hours: in recreational ballet, "hypermobility of the hip and ankle and longer training hours were risk factors for lower-extremity injury", and a modern dance company with more yearly hours had more overuse injuries. Social dancing all night adds hours of bent-knee steps, turns and sometimes heels on hard floors (our reading).
Floors matter, though the evidence is thin: none of the floors at three theatres met a sports surface standard, and "Intra-floor force reduction variability may have a stronger association with injury risk than mean floor force reduction magnitude", so an uneven floor may matter more than a hard one; on a sprung floor, dancers' knees bent slightly less and their ankles loaded more slowly on landing. No study compares injuries on sprung and hard floors.
Sources 36, 37, 38, 39
The meniscus and the ACL: uncommon in trained dancers, but they happenEmerging evidence
A twist or a landing can tear the meniscus or the ACL. In hip hop dancers at a London clinic, men's knee injuries were mostly meniscus injuries (45%). ACL tears are rare in trained dancers: in 298 elite ballet and modern dancers followed for 5 years, "The incidence of ACL injury was 0.009 per 1000 exposures", and "Landing from a jump onto 1 leg was the mechanism of injury in 92% of cases". In a Dutch classical company, though, the risk of a left ACL tear over a 10-year career was 7%, all landing a jump on the left leg in turnout with the knee falling inward, so the low rate isn't universal.
In the lab, "Dancers of both sexes and male team sport athletes landed similarly in terms of frontal-plane knee alignment, whereas female team sport athletes landed with a significantly greater peak knee valgus" (the knee falling inward). Years of training in landing and alignment may protect dancers, an idea no study has tested against injuries. A review that places dance among the lowest-risk activities for ACL tears takes its dance figure from the 5-year study.
Sources 4, 17, 30, 40, 41
Bendy knees, growing dancers and older social dancers
Knees that bend back (hyperextend) are common in dancers and usually harmless; our hyperextended knee guide says "Dancers and gymnasts: avoid hanging on the end of your range in standing positions, and keep a slight bend in the standing knee". Pain at a bump just below the kneecap in a growing dancer is often Osgood-Schlatter disease, or at the lower tip of the kneecap Sinding-Larsen-Johansson; our children's knee guides cover them. An ache in both knees from your mid-40s, stiff after rest, is often knee arthritis, which exercise helps, as our knee arthritis guide says.
When it isn't dancing: the causes the warning signs cover
Some knee problems need checking whatever caused them. The NHS asks for advice from NHS 111 for a knee that is very painful, won't move or take weight, is badly swollen or has changed shape, locks or gives way, or is red and hot with a very high temperature, and a 999 call or A&E after an injury with a crack, a changed shape or a numb, cold leg, which can be a broken bone. The NHS dislocated kneecap page asks you to go to A&E after a knee injury if the knee has changed shape, swelled very quickly, you felt a pop or snap, bone is showing or it's bleeding heavily, and to get help from NHS 111 if you think your kneecap came out of place and went back. A hot, swollen joint with sudden severe pain can be an infection (the NHS notes not everyone has a high temperature). Bursitis that hasn't improved after 1 to 2 weeks of looking after it needs a GP, and knees that bend back with joint pain, repeated sprains or tiredness can be part of joint hypermobility syndrome, which a GP can assess.
Other warning signs follow the pages behind them. The Ottawa knee rule, which asks for an X-ray after a knee injury if you can't take 4 steps or are 55 or over, was built and tested in emergency departments and missed very few broken bones: across 6 studies of 4,249 adults, its sensitivity was 98.5%. A throbbing, swollen calf or thigh can be a deep vein thrombosis (DVT), a lump behind the knee that suddenly gets more painful and swollen can be a burst Baker's cyst, and sudden breathlessness or chest pain can be a clot that has reached the lungs, the NHS says. Numbness around the genitals or bottom, or tingling that travels down the leg from the back, points to the back rather than the knee, as the NHS sciatica page explains. A pop at the front of the knee, then a dent and a knee you can't straighten, can be a torn quadriceps or patellar tendon, the AAOS says.
In a child, a pop below the kneecap can be a sleeve of cartilage and bone pulling off its lower tip: of 90 children and teenagers with this injury at one hospital, 71% were treated without surgery. The NHS asks for a 999 call or A&E if a child gets sudden pain in the hip, knee or thigh or can't put any weight on the leg, and an urgent GP appointment or NHS 111 for a limp; its growing pains and bone cancer pages explain why pain in one joint, a limp, swelling, a high temperature, unusual tiredness or bone pain at night needs a GP. Muscle breakdown (rhabdomyolysis) after a hard, unaccustomed session is rare but can harm the kidneys: 97 cases have been reported after indoor cycling classes, a college football team had a cluster after a workout of 100 back squats, a teenage athlete had it after an hour of wall sits, squats, lunges and jumps, and of 93 people admitted after spin classes, 73.1% had dark urine, so about a quarter didn't; a review covers how it happens and how to prevent it, and the NHS covers blood in the urine and acute kidney injury. Where symptoms such as catching or locking haven't settled after three months of non-surgical treatment, an MRI scan should be considered, a national programme on keyhole knee surgery says, and surgery may occasionally be needed if a kneecap keeps dislocating, nidirect says. Pain at the bump just below the kneecap, or at its lower tip, in a growing child is usually Osgood-Schlatter disease or Sinding-Larsen-Johansson syndrome, as the AAOS and two NHS trusts describe.
Sources 42, 43, 44, 45, 23, 46, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89
When a scan helps, and how it usually goesEmerging evidence
For an aching kneecap or tendon after dancing, no scan is needed at first: NHS inform expects most new knee problems to settle within 6 weeks, and scans can mislead, since tendon changes are often painless. An X-ray matters after a fall or a blow with the warning signs of a broken bone, and an MRI (magnetic resonance imaging) scan when a meniscus or ACL tear is suspected after a twist or landing with swelling, locking or giving way, or when kneecap or tendon pain doesn't improve with a few months of good rehabilitation, as our meniscus and ACL guides say.
The NHS says with knee pain "You should start to feel better in a few days", and NHS inform says new knee problems "should begin to settle within 6 weeks". Most dance injuries cost days rather than months: in a professional ballet company, "Mean injury severity was 7 days", though knee injuries caused some of the longest time away in ballet students. Kneecap pain in young dancers can come and go over years, jumper's knee usually takes months of tendon loading, and most Irish dancers seen at a clinic returned to full dance with physiotherapy and home exercises. No one can promise a date.
Sources 43, 7, 42, 47, 48, 5, 49, 50
