This report acknowledges the problems faced by industrial/organizational psychologists who must make personnel decisions involving physically demanding jobs. The scarcity of criterion-related validation studies and the difficulty of generalizing validity are considered, and a model of physical performance that builds on Fleishman's (1984) taxonomic work is described. Seven constructs of the model are defined within the context of three broad dimensions of performance: muscular tension, power, and endurance make up the muscular strength category; the cardiovascular endurance category is undivided; and flexibility, balance, and neuromuscular integration comprise the movement quality category. Examples of where each construct is important for performance are provided. Several hypotheses about the interrelationships among the constructs are presented. Finally, three sources of empirical support for the model are summarized: (1) an analysis of the physical demands of over 2,000 tasks from approximately 200 jobs, with results summarized in relation to the three major dimensions of the model; (2) an analysis of test scores from 12 studies concerned with occupational performance of adults, in which the 7 physical performance constructs of the model could account for all the interpretable factors identified across the studies; and (3) a compilation of tests from 8 studies that validated the tests as predictors of job performance and revealed that the tests were measures of muscular strength, cardiovascular endurance, balance, flexibility, and coordination. A four-page reference list is appended. (NRB)