The purpose of this study was to investigate the importance of subject-related risk factors for sports injuries, taking exposure time into account. At baseline in 182 healthy males and females (27 yr) the following subject-related risk factors were assessed: body mass index (BMI), maximal oxygen uptake (direct treadmill measurement), seven aspects of neuromotor fitness (MOPER fitness test), strength of the hamstring and quadriceps muscles(CYBEX), having sustained a sports injury in the 12 months preceding the baseline measurement (“previous injury”), and 16 psychological and psychosocial factors (measured with 8 standard, valid, and reliable questionnaires). For 1 yr, subjects were asked to make daily entries on a monthly log concerning all sports activities exceeding an intensity of 4 MET and all sustained sports injuries. Completed logs were returned by 139 subjects (75 males and 64 females). Fiftyone injuries were registered in 41 subjects. The overall incidence rate (IR) was 3.7 sports injuries per 1000 h of sports participation (95% confidence interval 2.8-4.9). For various subcategories, the following IR per 1000 h of sports participation were calculated: contact sports IR = 11.0 (95% CI 7.4-16.3); noncontact sports IR = 2.3% (95% CI 1.6-3.3); competition IR = 13.4 (95% CI 8.7-20.6); and training IR = 2.8 (95% CI 1.6-5.1). Data were analyzed by stepwise multiple logistic regression. The following five variables were independent and significant(P < 0.05) predictors of risk in sustaining a sports injury: dominance (odds ratio (OR) = 1.71; 95% CI = 1.44-2.03), vital exhaustion (OR = 1.85; CI = 1.22-2.86), stressful life events (OR = 1.84; 95% CI = 1.10-311); these ORs were calculated for an increase of 10% of the range of obtained scores, starting at minimum value. For total sporting time, the OR was calculated by taking the group with a total sporting time below the median(4050 h) as a reference (OR = 6.87; 95% CI = 2.09-22.55). For previous injury, subjects that had not sustained a sports injury in the 12 months preceding the baseline measurements served as a reference for the calculation of the OR (OR= 9.41; 95% CI = 2.80-31.58). These findings confirm that both exposure time and previous injury are more important predictors of sports injuries than psychological, psychosocial, physiological, and anthropometrical factors.
EMGO Institute, Faculty of Medicine, Vrije Universiteit, NL-1081 BT Amsterdam, THE NETHERLANDS; and Department of Psychonomics, Faculty of Psychology, University of Amsterdam, THE NETHERLANDS
Submitted for publication December 1994.
Accepted for publication January 1996.
This study was conducted with final support by the Dutch Ministry of Health, Welfare and Sport (grant no. 90-170).
Address of correspondence: Dr. Willem van Mechelen, M.D., Ph.D., EMGO Institute, Faculty of Medicine, Vrijie Universiteit, Van der Boechhorststraat 7-9, NL-1081 BT Amsterdam, The Netherlands.