Soldier performance and mood states following a strenuous road march.

Eighty-nine soldiers performed a maximal effort 20-km road march, carrying a total load of 46 kg. Compared to pre-march values, post-march marksmanship accuracy decreased 26% for number of target hits and 33% for distance from the centroid of the target. Maximal grenade throw distance decreased 9%, but there was no change in maximal vertical jump height. The Profile of Mood States questionnaire revealed an 82% increase in self-reported fatigue and 38% decrease in vigor. Significant decrements in some aspects of military performance occur when soldiers march rapidly with heavy loads over long distances.