Page 44 - Journal of Special Operations Medicine - Winter 2016

where larger water craft cannot effectively maneuver. maintain postural stability (i.e., SOM, VIS, VEST) when
When performing military tactical training or complet- the sensory input is accurate. The PREF score indicates
ing a mission, the SWCC must wear body armor and the subject’s ability to maintain postural stability using
TG on the craft and maintain proper postural stability inaccurate visual information.
to safely and efficiently complete the mission. The effect
of load carriage on SWCC is unknown. Procedures
Height and weight for each crewman with and without
The purpose of this study was to determine if body ar- TG were measured. The crewmen performed the SOT
mor and TG affects postural stability in SWCC. It was in accordance with NeuroCom’s standard operating
hypothesized that the addition of body armor and TG procedure based on each subject’s height. The crewmen
would negatively affect postural stability and, therefore, were instructed to maintain proper foot position and
may increase risk for lower extremity musculoskeletal to maintain their normal standing balance, with arms
injury. The results of this study will provide insight into to their side and while looking straight ahead. Crew-
the effects of load carriage on postural stability and po- men performed the NTG unshod, according to standard
tential need for physical training techniques to mitigate procedures, but wore tactical footwear during the TG
the negative effects that load carriage may have on pos- protocol. Researchers observed foot position through-
tural stability. out the protocol to ensure compliance with the manu-
facturer’s operation procedure. The harness provided by
NeuroCom was used only during the TG tests to catch
Methods in the event of a fall, but researchers ensured it did not
impede mobility. No falls were observed during testing.
Participants
Eight SWCC who cleared for full active duty participated TG and NTG tests were completed in a randomized or-
in this study (mean ± standard deviation [SD]: age, 27.1 der. Balance was scored for overall performance, each
± 6.9 years; height, 180.8cm ± 6.5cm weight, 90.7kg ± of the six conditions, and sensory system analysis scores
5.7kg). All subjects were informed of the testing pro- for SOM, VIS, VEST, and PREF. Normality was assessed
cedures and provided written informed consent prior using the Shapiro-Wilk test with statistical significance
to testing. This study was approved by the University set at p < .05. Data were not normally distributed; there-
of Pittsburgh institutional review board. The crewmen fore, Wilcoxon signed-rank tests were used to compare
were tested with TG and without tactical gear (NTG) in each subject’s performance on each postural stability
a randomized order. Each crewman wore standard op- variable between TG and NTG conditions with signifi-
erational gear, weighing a mean (±SD) of 21.7kg ± 1.1kg, cance set a priori at p < .05.
for TG tests that included body armor, blue weapons
(also known as plastic simulation weapons), plastic am- Results
munition magazines, and helmet and night optic devices.
The means, standard deviations, median values, and
Instrumentation interquartile ranges for each SOT variable (SOTcomp,
The NeuroCom Balance Manager Smart EquiTest (Na- SOM, VIS, VEST, PREF, and C1–C6) are included in
tus Medical Inc., http://balanceandmobility.com) was Table 1. The Wilcoxon signed-rank test revealed no dif-
used to determine postural stability. The apparatus is ferences in SOT performance for any of the postural sta-
equipped with two force sensors and a dynamic visual bility variables with and without wearing TG.
surround that are used to provide challenging support
and visual conditions. NeuroCom’s standardized proto- Discussion
col for the Sensory Organization Test (SOT) was used to
assess postural stability and consists of six conditions, The effect that load carriage has on SWCC postural
each having three consecutive trials. The six conditions stability, specifically SOT performance, is unknown.
(C1–C6) of the SOT are (1) eyes open with stationary Therefore, the purpose of this study was to determine if
support, (2) eyes closed with stationary support, (3) body armor and TG affect postural stability in SWCC.
eyes open with dynamic surround, (4) eyes open with We hypothesized that the addition of body armor and
dynamic support, (5) eyes closed with dynamic support, TG would decrease postural stability, but our hypothe-
and (6) eyes open with dynamic surround and support. sis was not supported. In our study, SWCC were able to
The SOT provides an overall composite score (SOT- maintain the same postural stability performance with
comp) and four sensory analysis scores: somatosensory the SOT when wearing 21.7kg ± 1.1kg on the upper
(SOM), visual (VIS), vestibular (VEST), and preference body as without the TG. The statistical analysis revealed
(PREF). These scores indicate the ability of the subject no significant differences between conditions for the
to use information from the indicated sensory system to SOTcomp, SOM, VIS, VEST, or PREF scores.

28 Journal of Special Operations Medicine Volume 16, Edition 4/Winter 2016