Optimum load for carriage by soldiers at two walking speeds on level ground

Physiological responses of soldiers while carrying different loads were studied to suggest optimum load that can be carried by an Indian infantry soldier comfortably at level ground at two different walking speeds. Ten physically fit male infantry soldiers walked at 3.5 and 4.5 km h−1 each on treadmill without and with loads of 4.4, 10.7, 17.0, 21.4, 32.4 and 40 kg for 10 min duration. Heart rate (HR), minute ventilation (VE), oxygen consumption (VO2) and energy expenditure (EE) were determined using K4b2 system. A linear increase in HR, VE, VO2 and EE with increasing external load was observed. The effect is more pronounced with speed than load. Based on physiological limit of 35% VO2max and linear regression equation loads of 36.1 and 21.3 kg are suggested as permissible for carriage on level ground at 3.5 and 4.5 km h−1 speeds, respectively. This combination of weight and speed is expected to improve the load carrying efficiency of the soldiers.Relevance to industryDeveloping countries mostly do not have load carriage standards of their own, either for Industry or Military. Results of this study will be of immense help in developing their own standards or to make use of these recommendations for the similar kind of population under specified conditions.