Ergonomic intervention and Optimization for maximum permissible loads to be carried in Sherpa mode based on physiological criteria

Abstract

The optimum load carrying capacity and maximum allowable work time at various slopes in the existing Sherpa mode of load carriage was determined based on 35% of maximum aerobic capacity. A convenience sample of 30 healthy agricultural who voluntarily signed an informed consent form participated in this study. The maximum loading capacity for a male is 50% of their body weight for a short duration and a minimum of 17% at 20% slope for a long duration. Considering the rate of perceived exertion in Sherpa mode of load carry, a basket holder was also conceptualized and developed. The silent features of the designed holder are (i) it can accommodate the wide range of existing baskets being used for Sherpa mode, (ii) shoulder straps were provided to transfer part load on the shoulder from forehead with adjustability to suit a wider range of population, (iii) the forehead pressure was distributed by enlarging the strap area on the head and (iv) cushions were also provided in back and straps for comfort. As per the experiment conducted in laboratory conditions, the recommended load carrying capacity and allowable work time for males and females was found higher than the existing one. It was observed that maximum enhancement in load carrying for males and females with basket holders was observed as 47 and 23%, at 20% slope for a longer duration of work, respectively. Similarly, the significant improvement in the allowable work time was also observed. The comparative discomfort score indicated enormous pain reduction at the neck and forehead.