Work capacity is the employees' ability to accomplish production goals without undue fatigue and without becoming a hazard to themselves or to coworkers. Work capacity is a complex composite of aerobic and muscular fitness, natural abilities, intelligence, skill, experience, acclimation, nutrition, and motivation. For prolonged arduous work, fitness is the most important determinant of work capacity.

Work Capacity

Years ago, crew bosses assessed a worker's capability by observing performance in preseason training. Those who measured up made the crew; those who didn't were reassigned or let go. Today a series of employment laws and regulations (Federal Uniform Guidelines on Employee Selection Procedures) have emerged. Minimum work capacity standards were developed to ensure physical qualifications for the job (Wildland Firefighter Health and Safety Report No. 4, Sharkey 2001). Based on extensive laboratory and field tests, the National Wildfire Coordinating Group has approved work capacity standards (NWCG 2009) for personnel involved in arduous, moderate, and light duties. The duties include:

Arduous-"Duties involve field work requiring physical performance calling for above average endurance and superior conditioning. These duties may include an occasional demand for extraordinarily strenuous activities in emergencies under adverse environmental conditions and over extended periods. Requirements include running walking, climbing, jumping, twisting, bending, and lifting more than 50 pounds; the pace of work typically is set by the emergency condition."

Moderate-"Duties involve field work requiring complete control of all physical faculties and may include considerable walking over irregular ground, standing for long periods, lifting 25 to 50 pounds, climbing, bending, stooping, squatting, twisting, and reaching. Occasional demands may be required for moderately strenuous activities in emergencies over long periods. Individuals usually set their own work pace."

Light-"Duties mainly involve office-type work with occasional field activity characterized by light physical exertion requiring basic good health. Activities may include climbing stairs, standing, operating a vehicle, and long hours of work, as well as some bending, stooping, or light lifting. Individuals almost always can govern the extent and pace of their physical activity."

Since 1975 firefighters have been required to take a work capacity test that determines minimum qualifications for wildfire suppression. Field tests now are used to assess work capacity (table 6.1).

Test performance is correlated to the aerobic and muscular demands of each category.

The required work capacity standards for wildland firefighters, incident management personnel, field workers, and agency personnel are listed in table 6.2. Where no requirement exists, recommendations for aerobic and muscular fitness are provided also.

Instructions for administering the Pack, Field, and Walk Tests may be found in the Work Capacity Test Administrator's Guide (Whitlock and Sharkey 2003). Before the fire season, firefighters should train to meet the required and recommended levels of performance.

Wildland firefighting can be hazardous, with long shifts performed in difficult environmental conditions. When emergencies arise, a firefighter must be able to escape to a safety zone and may have to help others do so. Field studies show a high correlation (0.87) between aerobic fitness and the time it takes to reach a safety zone. The higher the level of fitness, the more rapid the escape (Ruby and others 2003). Pack Test performance predicts aerobic fitness; completing the test in 45 minutes predicts an aerobic fitness score of 45 milliliters/kilogram-minute.