The Effects of a Combined Multi-Stressor Environment and Fatigue on Pistol Shooting Performance
Acute cold and hypoxia exposure are common environmental stressors to military personnel and can influence human performance (marksmanship, exercise capacity, and strength) in a variety of different ways. Despite both cold and hypoxia being potent independent environmental stressors, both of these environmental stressors commonly coexist in nature and are rarely studied together. It is currently unclear how combined exposure to acute cold and hypoxia will influence pistol shooting performance. Therefore, the present study aimed to determine how combined exposure to a multi-stressor environment will influence pistol shooting performance independently, and in combination with environmental exposure and exercise-induced fatigue. Six subjects consisting of four males and two females (age: mean ± SD = 28.5 ± 2.93 yrs.) in possession of a marksmanship badge or license took part in this research project. Subjects were exposed to three environmental conditions consisting of a baseline normoxic condition [24 °C ambient air and a simulated altitude of 1,067 m (FIO2 = 21%)], a cold normoxic condition (C-NORM), [10 °C ambient temperature and a simulated altitude of 1,067 m (FIO2 = 21%)], and a cold hypoxic condition (C-HIGH) [10 °C ambient air and a simulated altitude of 3,048 m (FIO2 = 14.3%)]. Throughout each of the three conditions, pistol shooting performance metrics (marksmanship, accuracy, and reaction time) were assessed following 30-min of acclimation and re-assessed following a fatiguing exercise protocol consisting of repetitive sandbag deadlifts. In addition to pistol shooting performance, physiological measurements consisting of heart rate, oxygen saturation (SpO2) muscle oxygenation (Total Saturation Index: [%TSI]), skin temperatures (hands and fingers), and human performance measurements such as isometric strength, and exercise capacity (sandbag deadlifts) were assessed throughout each condition. Results from the study indicated that 30-min of exposure to C-NORM and C-HIGH conditions did not influence pistol shooting performance. However, following the fatiguing sandbag deadlift protocol, there were improvements in pistol marksmanship throughout all conditions and improved pistol accuracy in the C-NORM condition. In addition, there were no differences in the number of sandbag deadlifts or maximal isometric strength performed on the mid-thigh pull throughout and across each environmental condition. Lastly, results from the physiological measurements indicated that heart rate was elevated following the fatiguing sandbag deadlift protocol, SpO2 values decreased throughout C-HIGH condition, and there were no differences between skin temperatures of the hands and fingers or muscle oxygenation between the C-NORM and C-HIGH conditions. These findings suggested that acute cold exposure and combined cold and hypoxia exposure did not influence pistol shooting performance (marksmanship, accuracy, or reaction time). However, it appeared that prior feedback from pistol shooting and thermal discomfort may have influenced subjects' exercise capacity during the fatiguing sandbag deadlift protocol which attributed to preserved fatigue accumulation, an increased level of arousal, and attentional focus leading to an increase in pistol marksmanship and accuracy. Increased levels of arousal were indicated through an apparent increase in sympathetic activation such as increased heart rate and preserved localized (%TSI) and systemic (SpO2) oxygenation that was present throughout and following the sandbag deadlift protocol across all environmental conditions.
Salmon, Owen Frederick, "The Effects of a Combined Multi-Stressor Environment and Fatigue on Pistol Shooting Performance" (2021). ETD Collection for University of Texas, El Paso. AAI28541292.