Jumper’s knee (patellar tendinopathy) is a common problem among athletes in sports like volleyball. The prevalence of patellar tendinopathy is 40-50% among high-level volleyball players and the condition is mainly chronic. Our knowledge of risk factors for patellar tendinopathy is based on cross-sectional or case-control studies.
This study is a cohort study with a baseline examination and continuous registration of defined risk factors with a clinical diagnosis of jumper’s knee as an end-point.
The subjects will be recruited among the players participating in the Toppvolley Norge (TVN) program, a three-year senior high school boarding school located in Sand, a town in south-west Norway with 1200 inhabitants and about 70 elite youth volleyball players aged 15 to 18 years.
During their three years at TVN the players consistently train and play 15-25 h/week as part of the school program. The project leader will collect data two times a year (in the autumn when school starts and in the spring), but there will be a continuously registration of training and jumper’s knee diagnose by the local physician and physioterpists.
The diagnosis of Jumper’s knee is based on a clinical examination alone: history of pain in the quadriceps or patellar tendons or their patellar in connection with training or competition, and tenderness to palpation corresponding to the painful area
- Training diaries: Training diary will be filled out by each player, and they register their total training exposure in volleyball, weight training, other sports, matches and injuries
- Baseline questionnaire: Height, weight, waist circumference and skin fold thickness
- Jump test: Jump tests will be done on a force plate to estimate vertical jump height. Two types of jumps will be tested: standing jump and counter movement jump
- Ultrasound: Ultrasound examination of quadriceps and patellar tendon of both knees. Tendon thickness, hypoechioc areas and neovascularisation are registered
- Genetics: Students will be tested with a blood sample to analyze some known genes with correlation to tendinopathy
The data collection is planned finished in spring 2010.