Virtual Reality Based Active Shooter Training Drill Increases Salivary and Subjective Markers of Stress.

Law enforcement personnel are required to respond to a variety of dangerous, potentially life-threatening high stress scenarios. Virtual reality (VR)-based training has been shown to attenuate stress responses; however, little is known about the acute stress response from VR exposure. This study examined the impact of participating in a VR-based active shooter training drill (ASD) on markers of physiological stress as well as potential differences in men and women. To examine the impact of participation in a ~50 sec VR-based ASD, 29 subjects (n = 29; 17 males, 12 females) participated in a quasi-experimental single group design. Saliva samples were collected and analyzed from 27 of the 29 subjects a total of four times 1) 30-min prior to, 2) 5-min prior to, 3) 5-min after, and 4) 30-min after the ASD and analyzed for α-amylase (AA) activity and concentrations of secretory immunoglobulin-A (SIgA), cortisol (CORT), and uric acid (UA). Participation in the ASD resulted in a significant (p < 0.05) increase in salivary stress markers AA and SIgA. In addition, lower concentrations of CORT and UA were found in women compared to men. These findings have implications for law enforcement and/or military personnel that may seek to implement a VR-based training into their training regimen. Future studies should investigate the impact of longitudinal participation in ASD interventions to determine if this is an effective training method to reduce stress responses to real life active shooter training drills.

Acute Resistance Exercise Reduces Postprandial Lipemia and Oxidative Stress in Resistance-Trained Men.

ABSTRACT: McAllister, MJ, Steadman, KS, Renteria, LI, Case, MJ, Butawan, MB, Bloomer, RJ, and McCurdy, KW. Acute resistance exercise reduces postprandial lipemia and oxidative stress in resistance-trained men. J Strength Cond Res 36(8): 2139-2146, 2022-Acute ingestion of a high-fat meal (HFM) results in significant increases in postprandial triacylglycerols (TAG) and markers of oxidative stress (OS). Combined aerobic and resistance exercise can attenuate postprandial lipemia; however, it is not clear if acute resistance exercise alone can reduce postprandial OS. The purpose of this study was to determine if acute resistance exercise can attenuate postprandial OS and to compare the effects of moderate versus high-intensity resistance exercise in this regard. Nine ( n = 9) moderately resistance-trained individuals completed 3 testing conditions in a randomized order as follows: (a) rest (no exercise), (b) moderate intensity (3 sets of 10 repetitions at 68% 1 repetition maximum [RM]), and (c) high-intensity resistance exercise (4 sets of 6 repetitions at 85% 1RM). Exercises included barbell back squat, bench press, straight leg deadlift, lat pull-down, upright row, and sit-ups. A HFM was ingested 12 hours after each condition. Blood samples were collected immediately before as well as 2 and 4 hours after ingestion and analyzed for TAG, cholesterol (CHOL), insulin, malondialdehyde (MDA), total nitrate/nitrite (NOx), glutathione (GSH), and advanced oxidation protein products (AOPP). When comparing 4 hour area under curve (AUC) data between conditions, AOPP demonstrated a significantly lower AUC after the moderate-intensity condition compared with resting condition. In addition, resistance exercise resulted in significantly higher plasma NOx concentrations as well as lower TAG and CHOL concentrations after HFM ingestion. Resistance exercise also prevented a decline in GSH that was induced by the HFM. These results demonstrate that acute resistance exercise can attenuate postprandial OS.

Barbell Squat Relative Strength as an Identifier for Lower Extremity Injury in Collegiate Athletes.

Case, MJ, Knudson, DV, and Downey, DL. Barbell squat relative strength as an identifier for lower extremity injury in collegiate athletes. J Strength Cond Res 34(5): 1249-1253, 2020-The aim of the study was to determine the efficacy of using the relative strength level of Division I athletes in One repetition maximum (1RM) barbell back squat as an identifier of seasonal lower extremity (LE) injury. One repetition maximum back squat (kg) and reported LE injuries were retrospectively collected for Division I male football (n = 46), female volleyball and softball athletes (n = 25). Maximum preseason relative (body mass normalized) back squat strength values were compared with 2 analyses of variance (p < 0.05) between injured and uninjured male (football) and female athletes (softball & volleyball). Relative back squat strength was significantly lower in injured athletes than uninjured athletes in both men (F = 6.03, p = 0.02) and women (F = 4.68, p = 0.04) with a moderate to large effect size (g = 0.86-0.85). These data indicate the potential of 1RM back squat relative strength serving as one tool in multi-factor preseason screening for LE injury risk in these sports. Male athletes with relative squat strength below 2.2 and female athletes below 1.6 in these sports could be more susceptible to LE injury over a season. Strength professionals should consider using body mass normalized 1RM back squats as a screening tool for seasonal LE injury risk in college athletes.