(29) REPEATED BOUTS OF HIGH INTENSITY SPRINTS IMPACT ACCURACY ON A WORKING MEMORY TASK IN ARMY ROTC CADETS.

Background: Military operations require soldiers to perform complex tasks in high-pressure situations. Research shows that cognitive resources deplete as a function of both external and internal stress. High-intensity functional training has stress-buffering benefits, which could mitigate cognitive decrements while performing strenuous physical tasks. However, acute exposures to high-intensity physical stress have had varying effects on cognitive function in previous research.

Purpose: To determine how acute exposure to repeated high-intensity sprints affects working memory task accuracy in Army Reserve Officer Training Corps cadets 

Methods: 40 cadets (5F, Mass:71.8±14.09kg, Height:172.8±8.4cm) participated during a physical training session. Phase 1:warmup and familiarization of the 2-back n-back working memory (WM) task. Each cadet had a practice and baseline trial. Phase 2: cadets completed a circuit of 4 rounds of 4 exercises followed by the n-back task. The exercise order was a plank, bodyweight reverse lunge, hand release pushups, and max effort 400m sprint. Immediately following the 400m sprint, cadets did the n-back task before restarting the circuit. Five minutes post-circuit, a final n-back task was performed. An ANCOVA was performed to examine the effect of stress duration on hit percent (H%), controlling for sprint time and median choice response time (med-CRT), while an ANOVA was conducted to examine the impact of stress duration on false alarm percent (FA%).

Results: The ANCOVA examined the relationship between H% and covariates of sprint time, median choice response time (med-CRT), and time. The overall ANCOVA model was statistically significant,(p=0.001, η² = 0.222). Individually, only med-CRT (p=.008, η² = 0.043), and time (p = 0.048, η² = 0.048) had significant effects on hit percent. Post-hoc analyses t-tests with Tukey HSD revealed that time 1 (T1) was significantly smaller than T4 for H% (p=.041, d=-0.623) (Figure 1). Analysis of the med-CRT effect on H% showed that for a 100ms increase in CRT, H% decreases by 0.028 (p=.008). 

The ANOVA revealed a significant main effect of time on FA% (p< .001, η² =.157). Post hoc analyses show there were significant differences between baseline (T0) (p< .001, d= -1.169), the reference time point (T1) (p< .001, d= -1.059), T3 (p< .001, d= -1.003), and T5 (p< .001, d= -1.225) with T4 (Figure 1).

Conclusions: Time under physical stress may increase hit accuracy but potentially at the cost of increasing FA for a working memory task. Research has shown that increased energy and blood flow can increase CRT and hit percentage. However, mental fatigue may set in depleting cognitive resources needed to accurately process incoming information thus increasing FA%.
PRACTICAL APPLICATIONS: Including training that increases anaerobic capacity and  CRT may improve working memory hit accuracy and decrease FA%, which are critical components of many go/ no go decision tactical skills and drills.

Acknowledgements: None