Progressive resistance training program for improving manual materials handling performance.

Occupations such as emergency medical care, fire fighting, and the military involve sudden bouts of high-intensity exertion, which are not performed on a regular or predictable basis. The physical stress of sudden, high-intensity exercise may result in a higher injury rate and diminished job performance in individuals who are not physically prepared. Occupations requiring frequent manual materials handling involve considerable exercise, and novice handlers can be expected to improve performance during the first month of employment simply by performing the task (Genaidy, Mital, and Bafna, 1989; Sharp and Legg, 1988). Once an acceptable level of performance is reached, day-to-day task execution does not provide sufficient physical stress to produce further increases in performance or strength. Progressive resistance training (or weight training) is generally accepted as an effective adjunct to the practice of technique for improving performance in sports. It follows that an effective training method for physically demanding occupational tasks would be performance of the task, along with supplemental progressive resistance training. Such a training method is not commonly implemented in industrial settings. For workers who perform intense lifting only occasionally, the frequent performance of simulated job tasks, for the purpose of building physical strength would be prohibitively expensive in terms of both resources and time. In addition, the equipment for taskspecific training is rarely available to industrial employees. Some corporations provide employees with exercise facilities, but the goal is to improve health not job performance. A program of progressive resistance training using carefully selected exercises may be a practical approach to strength training for physically demanding occupational tasks. Little information is available to show the effects of progressive resistance training on manual materials handling performance. Asfour and coworkers (1984) utilized progressive resistance box lifting and aerobic training and noted significant increases in strength, aerobic capacity, and one-repetition-maximum box lift following 6 weeks of training. Sharp and Legg (1988) implemented a psychophysical training program in which subjects trained for 4 weeks lifting a box adjusted to the maximum load they estimated they could lift for 1 hour at a rate of 6 lifts. min -1. Psychophysical training increased the box mass lifted for 1 hour. In a group of related studies, Genaidy and colleagues (1989, 1990, 1991) reported increases in task endurance time of 46 % to 1200 % for a series of manual materials handling tasks. Subjects were trained by performing the task to exhaustion and time to exhaustion served as the performance measure (Genaidy, Mital, and