Page 90 - JSOM Fall 2021

FIGURE 1 TOP LEFT: Image of subject performing the fire-and-move Susceptibility to enemy fire was determined using the follow-
portion of the tactical combat movement simulation. TOP RIGHT: ing equation with the accuracy of enemy forces set to 10%.
Diagram of the tactical combat movement simulation. The protocol
began with the marksmanship with cognitive workload (CWL) shots
assessment (A), then transitioned to the fire-and move simulation by Susceptibility to Enemy Fire = 1 – (1 – Accuracy)
performing 16 bounds (B), and returned to the marksmanship with
CWL assessment (C). BOTTOM: Image of a subject performing the Assessment of Treatment Blinding
marksmanship with CWL assessment. Subjects were sent an electronic survey (Qualtrics Labs Inc.,
https://www.qualtrics.com/) after the third and fourth visits to
determine if they perceived an effect from the supplement they
were provided (yes /no/not sure).
Statistical Analysis
An a priori power analysis determined that a minimum of 39
subjects was required to achieve 80% power, α < .05, and a
moderate effect size. Complete data were acquired from 31
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subjects. Incomplete data were available from eight subjects due
to injury not associated with the study (n = 1), failure to com-
ply with the testing timeframe (n = 1), scheduling conflicts (n =
1), failure to follow-up (n = 2), loss of student housing due to
COVID-19 outbreak (n = 2), and COVID-19 illness (n =1). Data
were analyzed for subjects with complete data using SPSS ver-
sion 25.0 (IBM, https://www.ibm.com/products/spss-statistics).
All descriptive and dependent variables were assessed for nor-
mality using a Kolmogorov-Smirnov test and boxplot analysis.
All analyses were conducted with and without outliers. Two-
way repeated-measures ANOVA tests were used to determine
the main effects of condition (PLA versus CAF) and time (pre-/
post-fire-and-move simulation) for marksmanship accuracy,
first shot reaction time, marksmanship reaction time, and cog-
nitive performance. Two-way repeated-measures ANOVA tests
were also used to determine main effects of condition (PLA ver-
sus CAF) and time (first three/last three bounds of the fire-and-
move simulation) for the bound duration, exposure time, shots,
and susceptibility to enemy fire. Significant main effects were
followed by post hoc pairwise comparisons (Bonferroni test).
bound was determined with the Position Fitness infrared tim- Post hoc values were reported as estimated marginal means ±
ing gate system (Position Fitness, https://positionfitness.com standard error of means. A paired sample t-test was used to de-
/products/infrared-sport). The infrared timing gates that in- termine the effect of condition (PLA versus CAF) on the fastest
dicated bound completion were placed at shoulder height. bound duration. Statistical significance was set at p < .05. Eta
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The infrared timing gates that indicated bound initiation were squared (η ) was used to indicate effect size.
2
started by the investigator due to subjects lying in the prone
position. The average bound duration and fastest bound du-
42
ration were determined for each condition. Subjects returned Results
to the marksmanship with cognitive workload after the final Marksmanship
bound was completed. Subjects were again presented with 12 Figure 2 shows reaction time pre-/post- fire-and-move simu-
target call-outs every 4 seconds that were interspersed with lation, first shot reaction time, and marksmanship accuracy
12 mathematical problems. between conditions. No main effect was found for condition
(p = .592) or time (p = .424) on marksmanship reaction time.
Modeling Susceptibility to Enemy Fire No main effect was found for condition (p = .601) or time
The model developed by Blount and colleagues was used to (p = .350) on first shot reaction time. No main effect was
determine susceptibility to enemy fire. The average bound found for condition (p = .960) or time (p = .127) on marks-
31
duration from the fire-and-move simulation was used to deter- manship accuracy.
mine exposure time to enemy fire. This was achieved by using
the following equation with the reaction time of enemy forces Cognitive Performance
set at 1 second. No main effect was found for condition (p = .280) on cogni-
tive performance. A significant main effect was found for time
2
Exposure Time = Bound duration – [F = (1,29) = 4.678, p < .05, η = .13) on cognitive perfor-
Reaction Time of Enemy Forces mance. The total number of correct answers to math problems
was lower (9.0 ± 0.4) after the fire-and-move simulation com-
The number of shots from enemy forces was determined using pared to before the fire-and-move simulation (9.6 ± 0.4).
the following equation with shooting cadence set to 1.3 shots/
second. Modeling Susceptibility to Enemy Fire
Figure 3 shows the parameters from modeling susceptibility
Shots = Exposure Time × Shooting Cadence to enemy fire for the first three and last three bounds of the

88 | JSOM Volume 21, Edition 3 / Fall 2021