Background Prior research has identified athlete-related risk factors associated with increased sports injury rate. Practice characteristics of young athletes have never been investigated in this respect.

Objective To assess the injury problem in a multi-sport setting of young athletes and to determine practice-related risk factors.

Design Prospective epidemiological study.

Setting Follow-up of young athletes of a Luxembourgish sport school from September 2008 to July 2009 (42 weeks).

Participants 190 athletes (14.9 ± 1.6 years) (65% boys) from 16 different sport disciplines.

Assessment of risk factors Practice-related characteristics (context, volume, frequency and subjective intensity).

Main outcome measurements Data pertaining to training and competition were recorded daily for each athlete. Standardised injury characteristics were registered. An injury was defined as an incident occurring during sport practice preventing the athlete to participate in at least one full training session or game.

Results From the 190 athletes, 74% sustained at least one injury during the observation period. Injury rate was 1.65 injuries per athlete; injury incidence was 3.72 injuries/1000 h. The risk of injury was six times higher (CI95% (4.70–8.12)) in competition than in training (13.60 and 1.96 injuries/1000 h, respectively). Two thirds of the injuries were of intrinsic nature (27% progressive and 40% acute non-contact injuries). In team sports athletes having sustained at least one intrinsic injury had, compared to those with no intrinsic injury, a lower number of practice sessions per day (0.83 versus 0.89 sessions/day; p=0.023), a higher percentage of intense sessions (40 versus 30%; p=0.007), a higher number of intense sessions per day (0.33 versus 0.27 sessions/day; p=0.047) and a higher proportion of days with two intense sessions (5.7% versus 2.7%; p=0.007).

Conclusion The relationship between practice characteristics and sports injuries should be further studied and might point to interesting prevention initiatives, provided that sports practice can be monitored.