Seasonal variations in injury rates in US Army ordnance training

Abstract

Objectives: This study assessed the effects of seasons and temperature on injury rates during U.S. Army ordnance advanced individual training. Methods: Injury data were collected each week at two clinics serving two geographically separated military training units. Weekly injury rates were calculated as the number of injured soldiers in each battalion (numerator) divided by the total number of soldiers in each battalion (denominator). A two-way analysis of variance examined weekly injury rates according to training unit and season of the year. Correlations between injury rates and average maximal temperatures were also examined. Results: Analysis of variance indicated significant differences in injury rates according to training unit (p = 0.04) and season (p < 0.01) but no significant interaction between unit and season (p = 0.16). Injury rates in the summer were higher than injury rates in the winter or autumn. Coefficients for correlations between weekly injury rates and weekly average maximal temperatures were 0.71 and 0.88 for the two training units. Conclusions: These data support previous work in U.S. Army basic combat training indicating a seasonal effect on injury rates. Higher environmental temperatures were associated with higher injury rates.