Common, and volleyball has few serious injuriesStrong evidence
Sore knees after volleyball are common, and most knee problems in volleyball build up from jumping rather than coming from one injury. The FIVB's injury surveillance found "Volleyball is a very safe sport, even at the highest levels of play", and the American Orthopaedic Society for Sports Medicine (AOSSM) says "volleyball injuries rank lowest for all major sports".
In Norwegian top-division players, injuries that cost at least a day ran at 1.7 per 1,000 hours of play, and in Dutch club players all injuries at 2.6 per 1,000 hours, with the ankle, not the knee, the commonest injury. Young players have lower injury rates than older ones: "junior volleyball athletes had lower injury rates compared to other sports practised in high school, and older athletes had higher injury rates".
Sources 1, 2, 3, 4, 5
Jumping, and jumper's kneeStrong evidence
Volleyball is a jumping sport, and a review of prevention strategies concludes "it appears evident that jumper's knee affects far more volleyball athletes than does acute knee trauma". Among 613 Norwegian elite athletes, "The prevalence of current symptoms was highest in volleyball (44.6%+/-6.6%)" (all men in volleyball), and among 891 Dutch non-elite athletes, "Prevalence was highest among volleyball players (14.4%) and lowest among soccer players (2.5%)"; "Jumper's knee is almost twice as common among male nonelite athletes compared with female athletes".
Elite players' symptoms had lasted a mean of 32 months. The FIVB data say it "rarely leads to time loss, in spite of substantial pain and reduced performance", so injury counts that only include missed play under-count it. These are surveys at one point in time: they show who has it, not what caused it.
Sources 6, 7, 8, 1
How much jumping: the studies conflictMixed evidence
In 141 young elite players followed for 4 years, "male gender, a high volume of volleyball training and match exposure were risk factors for developing jumper's knee", with the odds rising 1.72 times for each extra weekly hour of training and 3.88 times for each extra set of matches a week. Video of 11,943 jumps showed weekly jump counts in training from 50 to 666 between boys, and the authors suggest "Total jump volume may represent a more important risk factor for jumper's knee than total training volume". In professionals, "Setters performed the greatest volume of jumps (121 jumps/training session)", and "each player had at least 1 week with a twofold increase in jumps".
But in 65 elite men followed over three seasons with sensors, "The association between jump load and knee complaints risk remains unclear", and a review of risk factor studies found "There was no strong or moderate evidence that any investigated risk factor was associated with PT" (PT is patellar tendinopathy, jumper's knee). In Dutch basketball and volleyball players, the authors advise taking "the total tendon load" into account, including physically heavy work. So the jump load evidence conflicts: count your jumps and avoid sudden rises, but load isn't the whole story.
Sources 9, 10, 11, 12, 13, 14
Landing: the small studies disagree on how deep to bendMixed evidence
How a player lands may matter, but the studies are small and point different ways. Players with past jumper's knee "used a stiffer landing strategy, which may be a risk factor in the development of patellar tendinopathy", and less knee bend early in the spike landing went with past tendinopathy. An older study of 10 national team men linked tendon pain with "deep knee flexion angles", which is why the FIVB document warns against bending too deeply.
Sports Medicine Australia advises landing "on the balls of their feet with their knees and hips bent". In our reading, a soft, controlled landing with the knees over the toes, neither stiff nor collapsing, fits all of them, but no study has settled the best depth.
Sources 15, 16, 17, 18, 19
Kneecap painEmerging evidence
A review notes "Volleyball athletes often complain of anterior knee pain" (pain at the front of the knee). In 82 Japanese high school attackers, "The prevalence of knee pain was 19.5%", and in Australian athletes aged 11 to 15 in basketball, volleyball, Australian football and tennis programmes, "Nearly 40% of this cohort reported AKP during a pain provocation test" (AKP is anterior knee pain). Kneecap pain is a diffuse ache around or behind the kneecap, worse with squats, stairs and after sitting; our runner's knee guide covers it.
Sources 6, 20, 21
Growing players: Osgood-Schlatter and Sinding-Larsen-JohanssonEmerging evidence
In 956 Brazilian 12 to 15 year olds, "The prevalence of OS in the sample was 9.8%" (OS is Osgood-Schlatter), and regular sport during puberty went with it; in older Finnish data, it stopped training "for an average of 3.2 months". The American Academy of Pediatrics (AAP) says "Younger athletes may develop pain of the growth plate just below the knee cap called Osgood-Schlatter Disease (OSD) instead of patellar tendonitis".
Pain at the lower tip of the kneecap in a growing player is Sinding-Larsen-Johansson syndrome, where limiting painful activity "yields positive outcomes within two to eight months". NHS inform says "Future growth spurts can cause the pain to return". Growing pains are different: the NHS describes aching or throbbing in both legs in the evening or at night, gone by the morning, not a sore spot at the knee.
Sources 22, 23, 24, 25, 26, 27
Landings, twists and the ACLEmerging evidence
Acute knee injuries are a smaller share. The FIVB's medical commission says "Fortunately, volleyball players appear to be at relatively low risk for acute knee problems, such as injury to the anterior cruciate ligament". At FIVB events, "non-contact trauma and overuse were reported as the most common causes of knee injuries". In US college women, "Knee injuries accounted for 14% of women's collegiate volleyball game injuries", usually without contact, and among injuries inside the knee the meniscus (37.7%) and the side ligaments (33.6%) outnumbered the ACL (26.3%).
When the ACL goes, it is usually a landing: in an Italian surgical series, "The most frequent mechanism of injury was landing from a jump in the attack zone", and in Italian professional women, "Thirty-three (97%) were non-contact", 21 of 34 "occurred in landing from a jump attack". In US college sport, "Most ACL injuries to women occurred by a noncontact mechanism (60%)", and the AOSSM says "Like ankle sprains, most ACL injuries in volleyball players occur when a player lands awkwardly after jumping".
Sources 1, 28, 29, 30, 31, 2, 18
Under the net, floor dives and the beachEmerging evidence
"The majority of the injuries (86%) occurred at the net, mainly when landing after blocking (63%) or attacking (29%)", often on an opponent's or a teammate's foot. A rolled ankle is our sprained ankle guide's subject; a twisting landing can hurt the knee too.
Diving for a dig drops the knee onto the floor. The AAP says "Knee pads have been shown to reduce knee abrasions and contusions (bruises)". A bruise over the kneecap, or a soft swelling over or below it (a bursa), is our kneeling knee and knee bursitis guides' subject; a hot, red one needs checking the same day.
At the 2001 beach world championships, "Knee (30%), ankle (17%), and finger injuries (17%) accounted for more than half of all acute time-loss injuries", and "knee pain (12%)" was the second commonest overuse problem, but sudden injury rates are low on sand, and the FIVB document says jumper's knee is less common in beach players.
Sources 32, 33, 24, 34, 18
Who gets itEmerging evidence
Men get jumper's knee more often, and more training and more sets played went with more of it in young elite players. Middle blockers had the highest injury rate at FIVB events and liberos the lowest.
Sources 8, 9, 1
When a scan or test mattersEmerging evidence
Jumper's knee, kneecap pain and Osgood-Schlatter are diagnosed by examination, and scans don't predict who hurts: in young elite volleyball players followed for 11 years, "Although approximately 70% of tendons with structural changes at baseline were normal at follow-up, there was no clear relationship between structure and function".
After a twisting or landing injury, the NHS lists "Unstable, gives way when you try to stand, unable to straighten, may hear a popping sound during injury" among the signs of a torn ligament, tendon or meniscus. An X-ray rules out a fracture when the Ottawa knee rule in the warning signs says so, and a magnetic resonance imaging (MRI) scan matters after a pop with fast swelling, locking or giving way. In a child with a limp, the hip is examined and X-rayed.
Sources 35, 36
How it usually goesEmerging evidence
Aches settle within days. Jumper's knee is often slow: symptoms had lasted 32 months on average in elite athletes and 18.9 months in non-elite ones. In the largest trial, "There was a trend towards a higher return to sports rate in the PTLE group (43% vs 27%, p=0.13)" at 24 weeks (PTLE is progressive tendon-loading exercise). "Jumper's knee is not a self-limiting condition": over 11 years, young players who had it scored 81 against 90 for healthy knees on a 100-point knee score, and 7 of 37 (19%) retired from competitive volleyball because of it, so about four in five didn't. In an older 15-year follow-up of 20 male athletes (sports not named), "Jumper's knee causes mild but long-lasting symptoms after an athletic career".
Osgood-Schlatter interfered with full training for a mean of 7.3 months in old Finnish data, and "At 12 weeks, 16% returned to playing sport, which increased to 69% at 12 months" in a Danish programme. After an ACL reconstruction, return takes most of a year; our ACL guides carry the numbers. No one can promise a date.
Sources 7, 8, 37, 35, 38, 23, 39
When it isn't volleyball: the causes the warning signs cover
Some knee pain has causes volleyball didn't create, or needs more than a plan, and the warning signs follow the pages behind them. A knee that changed shape, swelled fast or went with a pop needs A&E, in the words of the NHS dislocated kneecap page, and the Ottawa knee rule, tested in emergency departments, picks out who needs an X-ray. A pop at the front of the knee with a knee you can't straighten can be a torn quadriceps or patellar tendon, as the American Academy of Orthopaedic Surgeons (AAOS) describes; steroids and some antibiotics can weaken these tendons. In children and teenagers, a pop below the kneecap can pull off a piece of bone or a sleeve of cartilage instead, as a case series of 90 young people describes. A repeat dislocation of the kneecap is when surgery is usually discussed, as nidirect explains.
A knee that is locked and won't straighten, a tear after a significant twist in a younger person, or a knee that keeps giving way needs to be seen: the NHS meniscus tear page, a BMJ guideline panel that makes an exception for a truly locked knee, two trials in adults up to 45 and a European consensus on repairing tears that can be stitched are behind those lines, and an NHS programme on knee keyhole surgery says when catching or locking that hasn't settled after about three months needs a specialist. The NHS page on why ACL surgery is done, a UK trial of reconstruction against rehab, a US ligament guideline and a review of inner knee ligament injuries say when a loose knee needs a surgeon, and an International Olympic Committee consensus says an injured child's knee needs a specialist, with an X-ray first.
A hot, red swelling over the kneecap after floor dives can be infected bursitis, which the NHS bursitis page says needs a GP, and spreading redness with a fever can be cellulitis or worse, as the NHS cellulitis page says; a hot, swollen knee can be a joint infection, which the NHS septic arthritis page says is urgent. A limp with knee or thigh pain in a child or teenager can come from the hip, as the NHS limping and irritable hip pages say, and a slipped growth plate needs checking the same day: NHS inform describes it, and in a UK national study of 486 children the slip worsened the longer diagnosis took. NHS inform lists the signs in a child's knee that need a GP, the NHS bone cancer page describes bone pain that is worse at night, and tender bumps below the kneecap are usually Osgood-Schlatter or Sinding-Larsen-Johansson, as the AAOS and two NHS trusts describe. NHS inform's kneecap pain exercises say when kneecap pain needs a physiotherapist, and Health New Zealand describes stress fractures of the shin. A swollen, throbbing calf can be a blood clot or a burst Baker's cyst, and sudden breathlessness a clot in the lungs, as the NHS pages on deep vein thrombosis (DVT), Baker's cyst and pulmonary embolism explain; someone who faints while exercising needs a 999 call, as the NHS fainting page says; and pain that travels down from the back is sciatica, in the NHS's words.
Sources 36, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 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
