Context: In orienteering, the number of injury-registration studies is limited. Most researchers have used a cross-sectional design during specific events and, therefore, have mainly identified acute injuries.
Objective: To determine the prevalence of injuries by registering acute and overuse injuries in adolescent elite orienteerers over 26 weeks and to study the variation of injury prevalence over the season and the potential risk factors.
Design: Cohort study.
Setting: Two high schools in Sweden with national orienteering teams.
Patients or other participants: All athletes (33 adolescent girls, 31 adolescent boys; age = 17 ± 1 years) from 2 high schools with orienteering teams.
Main outcome measure(s): We used a weekly Web-based questionnaire to identify the incidence and prevalence of injuries and training variables. Risk factors for injury were calculated using multiple linear regression techniques.
Results: The average weekly prevalence of overuse and acute injuries was 35.7% (95% confidence interval = 34.8%, 36.6%) and 1.7% (95% confidence interval = 1.3%, 2.1%), respectively; overuse injuries (78.0%, n = 85) accounted for the majority. The incidence of acute and overuse injuries was highest for the foot/lower leg (48.6%, n = 53), and 71.6% (n = 78) of all injuries affected the foot/lower leg and knee area. Time to the first reported injury was associated with training volume (β = 0.184, P = .001), competition time (β = -0.701, P = .009), running on asphalt roads (β = -0.348, P = .008), and running on forest surfaces and trails (β = -0.331, P = .007), with a model fit of r( 2) = 0.50 (intercept = 2.196, P < .001). During the study, we observed a weekly increase (0.3%) in the prevalence of overuse injuries in the foot/lower leg (r( 2) = 0.33, P = .001); the highest prevalence (26.9%) was at the beginning of the competitive season.
Conclusions: Overuse injuries, predominately in the foot/lower leg area, were more common than acute injuries in adolescent elite orienteerers. These injuries had the highest prevalence at the beginning of the competitive season; therefore, this period can be seen as a possible risk factor for sustaining overuse injuries in the foot/lower leg.
Keywords: athletes; runners; severity score; training load.