Physiological and perceptual responses during Sherpa mode of load carriage: Role of hip and shoulder belt supports
Keywords:Sherpa mode, heart rate, energy expenditure rate, body part discomfort, India.
In the Northeastern hilly region of India, manual load carrying system is still widespread due to lack of transportation infrastructure. It is not uncommon to see men and women routinely carry head-supported loads like Sherpa mode where a load slung on the back and supported by a strap around the forehead. This type of load carriage has been shown to cause significant postural discomforts, mainly on head, neck and shoulders. Therefore, this experiment was conducted to examine effects of hip belt and shoulder straps on Sherpa mode of load carriage for assessment of physiological and perceptual responses. It was hypothesized that the support on hip belt and shoulder straps supported in Sherpa mode would elicit lower physiological and perceptual responses than without supports. Ten agricultural workers participated in this study and carried 20% and 40% of their body weight while walking at 3 km/h on a motor-driven treadmill with the grade alternating at 0%, 5% and 10% uphill slopes. Results showed that the heart rate (HR), oxygen consumption (VO2) and subjective perceptual responses were significantly decreased by using the belt and straps supports in comparison to without supports. This research finding suggests that load transportation without supports is ergonomically inadvisable.