A brief critique of physiological employment standards for physically demanding public safety occupations

Roy J. Shephard


Background. The time to complete occupational circuits, estimates of maximal aerobic power and simple measures of muscle strength are currently used as employment standards where the safety of the public is judged at risk.

Purpose. To make a brief critique of the procedures presently used with a view to identifying on-going weaknesses in assessments.

Methods. Analysis has focused upon issues of task reactivity, task duration, test components and test accuracy, with particular reference to assessments of maximal aerobic power.

Results. Test reactivity may exaggerate apparent job requirements. Current tests are of a few minutes duration; extrapolation to longer periods of activity are limited by inter-individual differences, including a possible greater tolerance of prolonged activity in women. Physical effort may contribute less to successful task completion than the mode of approach, which is rarely assessed. The accuracy of physiological measurements of the individual remains a major concern, with errors in the prediction process, effects related to body mass, and substantial intra-individual test-retest variation.

Conclusions. The concept of objective employment standards for physically demanding public safety occupations is now well accepted. However, practical implementation of individual testing at a level of accuracy to avoid substantial misclassification is an on-going challenge.


Body mass; Energy costs; Fatigue; Intra-individual variation; Misclassification; Predicted aerobic fitness; Prolonged activity; Task reactivity

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ISSN: 19206216