Energy requirements and perceived body discomfort of the various sub tasks of manual sugar cane harvesting: A pilot study

Abstract

The main aim of this preliminary study was to assess the energy cost of the various sub tasks required of workers during manual sugar cane harvesting. A secondary aim was to assess body mass changes, levels of dehydration and body discomfort. Eight workers were randomly selected to participate in this pilot study and heart rates were recorded continuously throughout the work shift. On completion of work, the workers did a step test during which oxygen uptake and heart rate were measured. A VO₂-HR regression equation was calculated for each subject and from this, energy expenditure was calculated. Heart rates and energy expenditure were consistent across sub tasks with a mean VO₂ of 21.34 ml.kg^-1.min^-1 for the entire shift. The energy required per ton was significantly higher (P < 0.05) for the cutting task (1157 kJ.ton^-1) compared to the other two sub tasks while topping required the least energy per ton (385 kJ.ton^-1). Workers lost over 4% body mass during work and perceived the most discomfort in the lower back region

Keywords: energy expenditure, manual work, hydration, body discomfort