Tactical Gear does not Affect the Sensory Organization Test of Special Warfare Combatant-craft Crewman

Abstract

Naval Special Warfare’s Special Warfare Combatant-craft Crewman (SWCC) function primarily on small, high speed boats on oceans or river systems. Gear carried for protection and tactical operation may impact balance by moving the center of mass, altering sensory input, hindering response time, influencing mobility, and increasing risk of musculoskeletal injury. Research on how tactical gear affects the performance of sensory systems (somatosensory, visual, and vestibular) responsible for balance is limited. Dynamic posturography systems assess function and coordination of these systems with the Sensory Organization Test (SOT). PURPOSE: The purpose of this study was to determine if tactical gear affects performance of SWCC Operators on the SOT. METHODS: Eight SWCC Operators cleared for full active duty participated in the study (27.1 ± 6.9 yr, 180.8 ± 6.5 cm, 90.7 ± 5.7 kg). All subjects provided informed consent prior to testing. Subjects tested with tactical gear (TG) and no tactical gear (NTG) in a randomized order. Subjects wore standard operational gear for TG tests that included body armor, blue weapons, magazines, helmet and night optic devices (mean mass = 21.7 ± 1.1 kg). Each subject completed three trials of six conditions twice (TG and NTG). Balance was scored for overall performance (SOTcomp); each condition (C1-C6) which varies the challenge to each sensory system; and sensory system analysis score for the somatosensory (SOM), visual (VIS), vestibular (VEST) and preference (PREF). Data were not normally distributed therefore Wilcoxon Signed Rank tests were used to compare each variable (alpha = 0.05). RESULTS: No significant differences were found between SOT NTG and TG tests (median score NTG vs TG, p-value): SOTcomp 77.5 vs 74.5, p=0.932; C1 93.8 vs 93.3, p=1.0; C2 90.3 vs 87.7, p=0.161; C3 90.8 vs 87.8, p=0.123; C4 81.0 vs 84.2, p=0.161; C5 66.5 vs 63.5, p=0.779; C6 60.7 vs 59.0, p=0.889; SOM 96.0 vs 95.5, p=0.778; VIS 88.0 vs 91.0, p=0.068; VEST 70.5 vs 71.0, p=0.527; PREF 96.5 vs 97.0, p=1.0. CONCLUSION: SWCC Operators demonstrate no effects of wearing tactical gear during the SOT, indicating the basic function of sensory systems is not changed in static conditions. Further evaluation under more challenging and dynamic conditions is appropriate. Supported by ONR Award N00014-10-1-0912/N00014-11-1-0929.