Yuval Heled

Soldiers are often required to carry loads which impose biomechanical strain on the human body. This can adversely affect physical performances. Recently, wheel-based devices (WBD) were designed to reduce the load on the soldier. In the present study, a prototype of this newly developed WBD was evaluated. Thirteen volunteers performed three exercise protocols on a treadmill as follows: (1) no load; (2) carrying 40% of their bodyweight with a backpack or; (3) with the WBD. Data acquisition included: gait parameters, vertical ground reaction forces (VGRF) and contact pressure acting on the shoulder. Biomechanical analysis showed that the WBD decreased the contact pressure on the shoulder and the VGRF. However, greater gait variability, in terms of cycle-to-cycle gait line generation, was observed, which might point to a difficulty in maintaining stability while walking. The study suggests that WBD has a potential to reduce the biomechanical strain on the soldier while carrying heavy loads. Future potential adjustments for the development of a better WBD-based solution are suggested. Practitioner Summary: The present research observed the potential biomechanical advantages of using a wheel-based device designed to reduce the load on the soldier. It contributed to a lower mechanical force on the soldier’s body, yet causing modulations in gait control. Future design adjustments should be made to optimise the platform.

Background: Smoking has a thermogenic effect and is associated with low physical performance. Nevertheless, a direct, quantitative effect of acute smoking on exercise heat tolerance has not been reported. Methods: Sixteen healthy young male volunteers, eight cigarette smokers, and eight non-smokers participated in the study. All subjects performed a maximal oxygen consumption test (VO _2max ) and a standardized heat tolerance test (HTT) after at least 12 h without smoking under the following conditions: no nicotine exposure, 10 min after nicotine exposure (2 mg nicotine lozenge), and 10 min after smoking two cigarettes (0.8 mg nicotine in each cigarette, smokers only). Results: There was no significant effect of nicotine exposure on physiological performance and heat tolerance in the non-smokers group. In the smokers group, cigarette smoking, but not nicotine ingestion, resulted with higher heart rate (by 9±9 bpm) at the end of the HTT (p<0.05). Moreover, both smoking and nicotine ingestion increased smokers’ rectal temperature at the end of the HTT (by 0.24±0.16°C and 0.21±0.26°C, respectively, p<0.05) and were associated with higher sweat rate during the HTT (by 0.08±0.07 g/h and 0.06±0.08 g/h, respectively, p<0.05). Heart rate variability (HRV) analysis also revealed a higher LF/HF (low frequency/high frequency) ratio after exposure to nicotine and smoking in the smokers group compared with no exposure (2.13±2.57 and 2.48±2.76, respectively, p<0.05), indicating a higher sympathetic tone. Conclusions: According to this preliminary study, cigarette smoking and nicotine ingestion increase the physiological strain during a HTT in smokers. Acute smoking may, therefore, increase heat intolerance and the risk to heat injuries.

A common and unfortunate cause for heat stroke-related deaths in children is entrapment in closed vehicles. The aim of this study was to analyze the pathological consequences of such grave events. Autopsy reports of all children that were brought to a national forensic medicine center after being found dead in closed vehicles over a 21-year period (1995–2015) were reviewed. Data extracted were the circumstances of the events, child age, sex, height and weight, time, date and duration of entrapment, and environmental temperatures at the time of entrapment and the autopsy findings. Eight deceased children were brought to the forensic medicine center for autopsy, and seven families consented to the procedure. Autopsy findings included diffuse petechiae and hemorrhages of serosal membranes (n = 7/7) and lung congestion (n = 3/7). Conclusion: Typical autopsy findings following classical heat stroke in children include diffuse petechiae and hemorrhages and lung involvement. These findings are similar to those reported in adults that had died following exertional heat stroke—a very different mechanism of heat accumulation. Prevention of future events can possibly be obtained by public education on the rapid heating of closed vehicles, the vulnerability of children to heat, and the caregiver role in child entrapment. What is Known: • A common and unfortunate cause for heat stroke-related deaths in children is entrapment in closed vehicles. The pathological consequences of such grave events have not been previously reported. What is New: • This study is the first to describe autopsy findings from children who were found dead in parked cars. • Autopsy findings included diffuse petechiae hemorrhages of serosal membranes and lung congestion. • These findings are identical to those seen in adults following exertional heat stroke.

Nce. This is especially important for soldiers whose physical performance level may influence mission completion and survival. Recently, wheel-based devices (WBDs), designed to reduce the load on the soldier, have been suggested as a possible solution. Thus, the aim of this study was to evaluate the physiological effects of a proposed WBD prototype. Ten volunteers performed 3 exercise protocols on a treadmill as follows: without carrying any load, with a military backpack, and with the WBD. While using both modalities, they carried 40% of their body weight. Data acquisition included heart rate, body core temperature, oxygen consumption, and subjective comfort. Postural sway was also measured to evaluate the effect of WBD on standing balance. There were no significant differences between the physiological measures while using both modalities. Subjective comfort evaluation showed that the WBD may be more comfortable, yet it raises difficulty in maintaining balance while walking, as can be explained by the postural sway results. We suggest that the similarity in physiological strain while using the WBD was due to reduced walking efficiency in an attempt to maintain balance. It appears that the WBD may have some biomechanical advantages in reducing the subjective pain and pressure at the shoulder region, a matter that should be further examined together with other biomechanical measures....