Seasonal Differences in Performance of the Ranger School Qualifying Road March

William J Tharion, Anthony J Karis, Adam W Potter, Reed W Hoyt


The U.S. Army Ranger School conducts a 61-day training course several times per year to train soldiers in combat skills.  One of the qualifying tests is a timed road march.  Warmer weather imposes greater thermal strain on the body which in turn compromises endurance performance.  This presents a problem in assessing performance across classes and making the road march fair for all students since some will be doing this event in cold or cool conditions (winter, spring and fall classes), whereas others will be doing it in hot conditions (summer classes).  Purpose: To assess the influence of seasonal differences on road march performance.  Methods: Road march times and per-mile pace were obtained from three Ranger School course classes (total: n = 66; [spring: n = 24, summer: n = 23, and winter: n = 19]).  Road marches were ~19.3 km for the spring and winter marches and ~12.9 km for the summer march.  Heart rates (HRs) and core body temperatures (Tcores) were obtained throughout each march. Weather conditions were spring: air temperatures (Ta): 17.2 to 21.0 °C; relative humidity (% RH): 53 to 75%; summer: Ta: 24.4 to 25.0 °C, RH: 82 to 89%; and winter: Ta:  −4.4 to −6.2 °C, RH: 51 to 60 %.  Results:  The per-mile pace of the spring class (15:35 + 0:45) [min: sec] was significantly slower (p < 0.05) than the summer class (14:57 + 0:58) or the winter class (14:46 +1:19).  A significant main effect of Tcore was observed by class; with the summer class students exhibiting significantly (p < 0.05) higher Tcore than spring or winter students (spring: 37.7 + 0.4 °C; summer: 38.2 + 0.5 °C; winter: 37.7 + 0.5 °C).  Conclusions: The Ranger School’s goal of having equally challenging road marches across classes was not met.  Even with the shorter course, the thermal strain was greatest for summer students, and a greater number of spring class students passed the standard with less than maximum effort.


Army Ranger School, road march, backpack, military, performance, physiology

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