Abstract
Background:
Few studies have described running-related injury (RRI) in middle school cross-country runners.
Hypothesis:
The purpose of this longitudinal study was to determine the incidence of RRI by athletic exposure (AE) among middle school cross-country runners over a 25-year period and whether differences exist by sex.
Methods:
We studied 2009 athletes (1036 girls, 973 boys) who participated in interscholastic cross-country at a U.S. western state school between 1988 and 2013. RRI identified were those attributed to running in a cross-country practice or competitive event (meet). A RRI was further defined as any runner complaint that required the attention of the athletic trainer, regardless of time lost duration. Total athletic exposure (AEs) data was the sum of participation in practices and meets where the runners were at a risk for sustaining a RRI). Incidence rates per 1000 AEs (total number of RRIs/total number of AEs) were calculated for overall incidence, and for practices/meets, body location, RRI type, and RRI severity (time lost from participation due to RRI). Rate ratios [RR] and 95% confidence intervals (CIs) were used to compare RRI rates.
Results:
A total of 872 RRI were observed for an overall RRI rate of 9.3/1000 AEs. Girls (10.4/1000 AEs) had a higher RRI rate than boys (8.2/1000 AEs) (RR=1.26, 95% CI: 1.1-1.4; p=0.0008). Most RRIs were mild ([no time lost] 3.5/1000 AEs) or minor ([1-7 days lost] 5.6/1000 AEs) in severity. Moderate (8-21 days lost) and major (22+ days lost) RRIs rates were 0.3/1000 AEs and 0.01/1000 AEs, respectively. Overall, the RRI rate during practices (10.5/1000 AEs) was over twice the RRI rate in meets (3.8/1000 AEs) (RR=2.74, 95% CI: 2.1-3.5; p<0.0001), with similar patterns for girls and boys. The incidence of RRI was highest at the knee (2.7/1000 AEs), ankle (1.9/1000 AEs) and shin/calf (1.8/1000 AEs). Tendinitis (5.9/1000 AEs), strains (1.8/1000 AEs), and sprains (1.3/1000 AEs) were the most common RRI types), and similar for girls and boys. For specific RRI type, the incidence was highest for patellar tendinitis (1.3/1000 AEs), shin splints/tibial stress syndrome (1.3/1000 AEs), and ankle sprains (1.1/1000 AEs).
Conclusion:
Findings from this study suggest that the risk of RRI was greater for girls than boys in middle school cross-country over a 25-year period. The risk of RRI was greater during practices than in meets, and most RRIs caused minimal or no time-lost from participation, likely indicating ideal early RRI identification and management.