| Sumario: | Two studies examined the reliability and validity of an index of perceived physical effort used to assess the metabolic and ergonomic costs of task performance. In the first study, tasks whose actual metabolic costs were available from the work physiology literature were rated by subjects (n = 50) who had no knowledge of those costs. Rating scales included a perceived physical effort scale and nine physical ability requirement scales. Results indicated high correlations between two indices of metabolic costs and ratings of physical effort (r = .75 and .72, respectively). High correlations were also obtained between metabolic costs and the ratings of various strength and stamina factors. In the second study, subjects (n = 20) actually performed 24 separate manual materials-handling tasks whose ergonomic costs (work = force × distance) were calculated. Each completed task was rated on. the index of perceived physical effort. Results indicated a substantial relationship (r = .88) between actual foot-pounds of work and the obtained ratings of physical effort. Implications of the results are discussed in terms of the psychometric properties of the index and its usefulness as a job analysis method for physically demanding work.
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