Shoulder-Fired Weapons with High Recoil Energy: Quantifying Injury and Shooting Performance

摘要

Sufficient information is not available to determine health hazards associated with weapon recoil. This study assessed the injury response in U.S. Army soldiers after firing a shoulder-fired weapon producing recoil energy at the upper limit authorized. Additionally, the authors observed injury rate and potential injury risk factors. Fifteen infantrymen fired 15 shots using a weapon system producing 59.09 ft-lbs of recoil energy. Markers of injury assessed pre- firing, immediately post-firing, and 24, 48, 72 and 96 hours post-firing included subjective pain, pain-pressure threshold, bruising, range of motion, strength, a lifting task, and laboratory markers. Thermal imaging and MRI were used to assess skin temperature and edema. Data were analyzed using repeated- measures ANOVA, Pearson correlations, and descriptive statistics. All 15 volunteers exhibited bruising at the anterior shoulder, and 11 reported pain with motion post-firing. Fourteen volunteers (93%) sustained evidence of soft tissue injury on MRI. Three (20%) sustained facial lacerations. Skin tissue temperature increased immediately post-firing and returned to baseline 24 hours later. Dominant handgrip strength had the best predictive value for injury severity on MRI. The authors conclude that soldiers are at risk for soft tissue contusions and lacerations at the upper threshold of allowable recoil energy. Injury was characterized by elevated skin temperature, pain with motion, and decreased pain threshold immediately post-firing. Signal intensity changes on MRI were consistent with muscle contusion for up to 96 hours post-firing. (21 tables, 23 figures, 55 refs.).