An indirect method to assess the energy expenditure of manual labourers in situ

Scott, P.A. and Christie, C.J. (2004) An indirect method to assess the energy expenditure of manual labourers in situ. South African Journal of Science, 100 (11 & 12). pp. 694-698. ISSN 0038-2353




The aim of ergonomics is to identify any incompatibility between worker capabilities and the demands of their job. It is therefore desirable that in a developing country such as South Africa we have some basic, yet valid and usable means of measuring worker responses to physically demanding manual tasks. Extensive ergonomic research has been conducted in the controlled environment of laboratories around the globe, but only a limited number of investigations have been conducted in the workplace. This is due to the impossibility of controlling the extraneous factors such as the environment and changing workloads while assessing worker responses, plus the impracticality of using hi-tech equipment under difficult conditions on unsophisticated workers. The likelihood of obtaining ‘natural’ responses thereby is low. The focus of this study was to establish a less invasive means of assessing the physiological responses (specifically energy expenditure) of manual labourers working in the field. Twenty-three forestry stackers were assessed. Heart-rate responses were recorded during a full shift, after which the workers participated in a submaximal incremental step test. Subjects were fitted with a gas analyser, and heart rate and oxygen consumption responses were measured throughout the 12-min test. These data were used to establish a regression equation based on the relationship between heart rate and oxygen consumption (r² = 0.49; r = 0.69). Using this equation (y=0.26x – 6.42), one can measure heart rate in the field and predict the energy cost of manual tasks.

Item Type:Article
Additional Information:Rhodes Centenary issue
Uncontrolled Keywords:ergonomics, heart rate, oxygen consumption, South Africa, manual labour, miners, soldiers, energy expenditure assessment
Subjects:Y Unknown > Subjects to be assigned
Divisions:Faculty > Faculty of Science > Human Kinetics & Ergonomics
ID Code:138
Deposited By: Rhodes Library Archive Administrator
Deposited On:25 Aug 2005
Last Modified:06 Jan 2012 16:17
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