The effects of gender, team size, and a shoulder harness on a stretcher-carry task and post-carry performance. Part I. A simulated carry from a remote site

This study examined the effects of gender, two- vs. four-person teams, and use of a shoulder harness vs. a hand carry on the ability of participants to simulate the transport of patients during a prolonged stretcher carry, and to simulate the defense and medical treatment of patients following the stretcher carry. Participants carried a 6.8-kg stretcher containing an 81.6-kg manikin at a constant rate of 4.8 km/h for as long as possible, up to a half hour. Dependent measures included carry time, weapon firing, fine-motor coordination, heart rate, oxygen uptake, perceived exertion, and subjective symptoms. Analysis of variance and post-hoc Newman-Keuls comparison of means revealed that men carried stretchers longer than women (p < 0.05). Harness use resulted in the stretcher being carried longer (23.1 ± 8.9 vs. 6.1 ± 5.9 min), at lower heart rates (141.9 ± 17.9 vs. 149.9 ± 14.7 beats per min), at slightly higher intensity (46 ± 8 vs. 42 ± 7% VdotO2max) (p < 0.05), and with less fatigue in the forearm and hand (p < 0.05). Four-person teams maintained pre-carry fine-motor and marksmanship scores and carried longer (16.9 ± 11.0 vs. 12.3 ± 11.4 min), while working at a slightly lower intensity (43 ± 8 vs. 45 ± 8% VdotO2max), compared with two-person teams (p < 0.05). Use of four-person teams with a harness resulted in an 8-fold increase in carry time, compared with two-person hand-carry teams (24.5 ± 9.0 vs. 3.0 ± 1.8 min). Four-person teams with a shoulder harness are therefore recommended for prolonged carries.