It is the operational effectiveness of the work force which should provide the basis for physical selection criteria for occupations where performance is of paramount importance. Such occupations include the Armed Forces, the Fite Service, and to a lesser extent the Ambulance Service, the Police Force and heavy industry. Operational effectiveness is ultimately dependent upon the ability of an individual to perform the job. If the job demands approach or exceed the physical capacities of employees, efficient and effective performance is precluded and the risk of injury is increased (Chaffin 1974; Chaffin et al 1978). However, at present only minimal efforts are made to screen applicants to these physically demanding occupations.