The primary purpose of this study was to examine lateral deviations in centre of pressure as a result of an extreme duration load carriage task, with particular focus on heel contact. Twenty (n=17 males, n=3 females) soldiers from a Special Operation Forces unit (body mass: 80.72±21.49kg; stature:178.25±8.75cm; age: 26±9yrs) underwent gait plantar pressure assessment and vertical jump testing before and after a 43km load carriage event (duration 817.02[32.66]min) carrying a total external load of 29.80 (1.05)kg. Vertical jump height decreased by 18.62%±16.85% (0.30±0.08m to 0.24±0.07m) p<.001. Loading peak and mid stance force minimum were significantly increased after load carriage (2.59±0.51BW vs. 2.81±0.61BW; p=.035; dGlass=0.44 and 1.28±0.40BW vs. 1.46±0.41BW; p=.015 dGlass=0.45, respectively) and increases in lateral centre of pressure displacement were observed as a result of the load carriage task 14.64±3.62mm to 16.97 ±3.94mm p<.029. In conclusion, load carriage instigated a decrease in neuromuscular function alongside increases in ground reaction forces associated with injury risk and centre of pressure changes associated with ankle sprain risk. Practitioners should consider that possible reduction in ankle stability remains even once the load had been removed, suggesting soldiers are still at increased risk of injury even once the load has been removed
