Background The jumper's knee (JK) is a difficult-to-treat overuse injury of the patellar and quadriceps tendon with a very negative impact on the careers of many athletes. The prevalence of JK among non-elite athletes from different sports and its aetiology are unknown.

Objective To determine the prevalence of JK in non-elite athletes from different sports and to determine potential risk factors for JK.

Design Cross-sectional survey.

Setting Male and female non-elite athletes.

Participants We interviewed 891 male and female non-elite athletes from seven popular sports in the Netherlands: basketball, volleyball, handball, korfball, soccer, field hockey and athletics.

Assessment Using a specially developed questionnaire, information was obtained about individual characteristics (age, height and weight), training background, previous and actual knee problems and the VISA-P score.

Results The overall prevalence of current JK was 8.5% (78 out of 891 athletes), showing a significant difference between sports with different loading characteristics and playing surfaces. Prevalence was highest among volleyball players (14.4%) and lowest among soccer players (2.5%); it was significantly higher among male athletes (51 out of 502, 10.2%) than female athletes (25 out of 389, 6.4%) (÷2=3.91, p=0.048). Mean duration of symptoms was 18.9 months (SD 21.6; range 2.0–59.8). The mean VISA-P score of the athletes with JK was 71.4 (SD 13.8). Age, height and weight were significantly different between athletes with JK and those without.

Conclusion Prevalence of JK is high among non-elite athletes and varies between 14.4% and 2.5% for different sports. JK is almost twice as common among male non-elite athletes compared to female athletes. Different sport-specific loading characteristics of the knee extensor apparatus, playing surface, age, height and weight seem to be risk factors associated with patellar tendinopathy.