NEW YORK, June 20 (Reuters Life) - One in every 40 elite soccer players will have to sit out games or practices because of "jumper's knee," an injury more commonly found in basketball and volleyball players, according to a study.
The injury, known formally as "patellar tendinopathy," involves the tendon that connects the kneecap to the tibia, the larger and stronger of the two bones in the leg below the knee. It has no known cure and no clear prevention strategy.
"The rate and severity of many of the overuse complaints (such as jumper's knee) have raised discussion about how to monitor and adapt load on individual players," said lead researcher Martin Hagglund, from Sweden's Linkoping University.
In his study, published in the American Journal of Sports Medicine, Hagglund and colleagues recorded injuries that caused players on 51 elite male European soccer teams -- a total of more than 2,000 athletes -- to miss games or practice time.
Over the course of almost a decade, team doctors and trainers reported 137 cases of jumper's knee, accounting for 1.5 percent of all injuries. An average of 1 in 40 players missed time due to that injury each season.
Athletes who spent more hours training and in competition were more likely to get jumper's knee, but there was no difference in injury rates based on whether teams played on natural grass or artificial turf -- a harder surface that some believe may increase the risk of injury.
Most of the injuries caused players to miss less than a week on the field, but 1 in 10 was severe, taking players out for a month or more.
The injury typically has a gradual onset, said Roald Bahr, from the Norwegian School of Sport Sciences in Oslo, who was not involved in the current study.
"It could make itself known in one training session, but usually more gradually over weeks or even months," he told Reuters Health.
"In the beginning there's just a slight ache, but as you continue playing it becomes more and more bothersome."
Bahr's research found that 1 in 7 elite athletes across a range of sports reported symptoms of jumper's knee.
Hagglund said if players start to develop symptoms, an adapted training program -- one that puts less force on the tendon -- could help reduce the injury's severity.
"The re-injury rate is high and the condition may be more severe and longstanding if early warning signs are ignored and if the athlete (returns) to play too soon with inadequate rehabilitation," he added.
Bahr, however, said many players never take time off and just play through the pain, perhaps because there's no cure-all treatment. Most simply do physical therapy for the tendon.
He added that the injury is most common in players who have recently made a sharp increase in the amount of training they do, and the intensity of that training, such as when athletes start playing on an elite or professional team.
"The bottom line of why this occurs, we think, is: too much, too often, too soon. Too much training, training too often, and increasing training loads too quickly," he said. SOURCE: bit.ly/mpE9bK
Reporting by Genevra Pittman; editing by Elaine Lies