Center of Pressure, Vertical Ground Reaction Forces, and Neuromuscular Responses of Special-Forces Soldiers to 43-km Load Carriage in the Field

in Journal of Applied Biomechanics
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  • 1 Queen Mary University London
  • 2 Canterbury Christ Church University
  • 3 St George’s University
  • 4 424 General Military Training Hospital
  • 5 32 Marine Corps Brigade
  • 6 Addenbrooke’s Hospital
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The primary purpose of this study was to examine lateral deviations in center of pressure as a result of an extreme-duration load carriage task, with particular focus on heel contact. A total of 20 (n = 17 males and n = 3 females) soldiers from a special operation forces unit (body mass 80.72 [21.49] kg, stature 178.25 [8.75] cm, age 26 [9] y) underwent gait plantar pressure assessment and vertical jump testing before and after a 43-km 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%) from 0.30 (0.08) to 0.24 (0.07) m, P < .001. Loading peak and midstance force minimum were significantly increased after load carriage (2.59 [0.51] vs 2.81 [0.61] body weight, P = .035, Glass delta = 0.44 and 1.28 [0.40] vs 1.46 [0.41] body weight, P = .015, Glass delta = 0.45, respectively) and increases in lateral center of pressure displacement were observed as a result of the load carriage task 14.64 (3.62) to 16.97 (3.94) mm, P < .029. In conclusion, load carriage instigated a decrease in neuromuscular function alongside increases in ground reaction forces associated with injury risk and center of pressure changes associated with ankle sprain risk. Practitioners should consider that possible reductions in ankle stability remain once load carriage has been completed, suggesting soldiers are still at increased risk of injury even once the load has been removed.

Scales is with the Queen Mary University of London, Whitechapel, London, United Kingdom. Scales, O’Driscoll, Coleman, and Brown are with the Canterbury Christ Church University, Canterbury, Kent, United Kingdom. Giannoglou is with the School of Cardiovascular Sciences, St George’s University of London, London, United Kingdom; and the 424 General Military Training Hospital, Thessaloniki, Greece. Giannoglou, Gkougkoulis, Ntontis, and Zisopoulou are with 32 Marine Corps Brigade, Volos, Greece. Ntontis is also with Addenbrooke’s Hospital, Cambridge, United Kingdom.

Scales (j.scales@qmul.ac.uk) is corresponding author.
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