Date of Award

Spring 2012

Document Type

Thesis

Degree Name

Master of Science in Education (MSEd)

Department

Human Movement Sciences

Program/Concentration

Exercise Science and Wellness

Committee Director

David Swain

Committee Member

Steven Morrison

Committee Member

Stacie I. Ringleb

Call Number for Print

Special Collections LD4331.E44 M653 2012

Abstract

Expeditionary warfighters in the military have the responsibility of being ready to deploy on short notice to any part of the world and be able to effectively complete their mission even if deployed to altitude. Studies demonstrate that altitude can significantly effect heart rate, ventilation rate, arterial oxygen saturation (SaO2) and cognition. Decrements in these areas could lead to a reduction in shooting accuracy. Only two studies have looked at the effects of marksmanship at various altitudes and their results are inconclusive. This study evaluated the effects of acute hypoxia on marksmanship and the effect of a physical exertion task on marksmanship. Subjects performed a shooting task prior to a 60-sec run on a treadmill at 7.5 mph. Immediately following the run subjects completed 3 more shooting trials with 30 sec rest in between trials 2, 3 and 4. This protocol was performed in a randomized order at simulated altitudes of 162 m (approximately sea level, SL), I 015 m (1K), 2146 m (2K), 3085 m (3K) and 3962 m (4K). Altitudes were simulated by having the subjects breathe a reduced oxygen concentration. SaO2, heart rate and ventilation rate were recorded during 5 minutes of baseline rest, before and after each shooting trial and the run. Results indicated significant effects of altitude and exercise on marksmanship. The shooting scores at 4K were significantly lower than those at all other altitudes. There was a strong trend for scores at 3K to be lower than those at SL and IK. The shooting score in trial 1 was significantly higher than that in all other trials. Some recovery of marksmanship following the run was exhibited by scores in trial 3 being greater than in trial 2. Altitude and exercise both significantly reduced SaO2 values. Heart rate did not change with altitude, but trial had a significant effect on heart rate where trial 1 (prior to the run) was significantly lower than all other trials. Altitude and trial both had a significant effect on ventilation rate. Altitude had a significant effect on resting SaO2 and ventilation variables where resting heart rate did not change over altitudes. There was a strong positive correlation (r = 0.84) between marksmanship scores and SaO2. There was a strong inverse correlation (r = 0. 72) for ventilation rate with marksmanship scores, and a modest inverse correlation (r = 0.54) for heart rate and marksmanship. These findings demonstrate that increasing altitude impairs marksmanship, with a threshold at approximately 3000 m. The decreased marksmanship is closely related to decreased oxygen availability in the blood. This hypoxemia could decrease marksmanship due to impaired cognition and increased ventilation, the latter increasing movement of the chest wall.

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DOI

10.25777/0546-3322

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