Cardiorespiratory changes with compact backpack system and distributed mode of load carriage.

In Indian Army, soldiers normally carry 21.4 kg in backpack (BP), haversack, and web distributed in different parts of the body and rifle in hand. This load distribution is unequal, may involve excess energy expenditure, mostly uncomfortable, and restricts the normal movement of the hand carrying rifle. A new BP has been developed which accommodates the rifle on sides leaving the hands free. Physiological evaluation of load carriage [21.4 kg in the existing Load Carriage ensembles (LCe) and in the new BP] and without load was carried out on a group of Indian Army soldiers (n = 8) to understand the efficacy of the new BP vis-á-vis the existing one at 4.5 km/h speed at level ground and at 5% gradient on a treadmill in controlled laboratory environment. Heart rate, oxygen consumption, relative work load and energy expenditure were determined and one-way repeated measure ANOVA was applied to compare the results. All the physiological parameters showed higher responses in distributed mode in comparison to compact mode. However, the differences were not significant. The study may be carried out on a larger sample size to find out the better efficacy of compact mode of load carriage over the distributed mode.