Test Development

Since 1975, Federal land management agencies have used a 5-minute step test to qualify wildland firefighters. New laws (such as the Americans with Disabilities Act), field experience, and research concerning long-term work capacity have led to a reexamination of the selection procedure. This 1994 study was the initial step in the search for a new test. Eighteen volunteers (nine male, nine female, all from 20 to 36 years old) performed leg tests of maximal oxygen intake, arm tests of peak VO2 and sustained (30-minute) performance, a battery of muscular fitness tests, and a field (pack) test, which consisted of a 4.83-kilometer (3-mile) hike over level terrain while wearing a 20.5-kilogram (45-pound) pack. Blood lactate measures were recorded after each test. The analysis was intended to determine the relationship of the candidate (pack) test to the existing step test and to identify factors correlated with the pack test. Results showed significant differences in muscular fitness measures between males and females, but neither leg VO2 max nor pack test differences were significant. The pack test was significantly related to the leg VO2 max (r = -0.579) and to muscular fitness measures, including leg press (r = -0.553) and pullups (r = -0.501). The pack test correlated to arm peak VO2 (r = -0.52), the arm VT (r = -0.592), and the sustained arm endurance test (r = -0.707). Multiple regression (R) analysis of pack test performance compared to tests of aerobic (arm and leg VO2 max, arm endurance, pack test lactate) and muscular (leg press, pullups) performance yielded R = 0.846 (R2 = 0.72). The results indicate that performance on the pack test involves components of aerobic and muscular fitness, and that a time of 45 minutes for the 3-mile test predicts the current fitness requirement of 45 milliliters per kilogram-minute.

Development of a job-related work capacity test for wildland fire-fighters, Sharkey, B., Rothwell, T., and DeLorenzo-Green, T., Medicine and Science in Sports and Exercise. 26: S88, 1994.

This 1995 study investigated alternative work capacity tests based on a comprehensive job analysis that identified tasks requiring strength and endurance of the legs and upper body. Eight male and seven female volunteers performed:

• Direct (treadmill) and indirect (step test) tests of maximal oxygen intake
  
  
• Muscular fitness tests (bench press, pulldowns, pushups)
  
  
• A field pack test consisting of a 4.83-kilometer (3-mile) hike over level terrain while wearing a 20.5-kilogram (45-pound) pack (performed with and without a respirator)
  
  
• A 5-minute simulated fireline construction test

Subjects also carried a pack and simulated line-building on a treadmill to determine the energy cost of those activities. Results indicated that the energy cost of the pack test at 4 miles per hour was 22.2 milliliters/kilogram-minute, which is similar to the documented cost of firefighting duties, including line construction (22 milliliters/kilogram-minute). There was no significant difference between males and females on the pack test, but there were differences between males and females on the fireline test (161 feet for males, compared to 109 feet for females; p < 0.013) and the muscular fitness tests (p < 0.0001). There was no significant difference in pack test performance with or without a respirator, and the trials were highly related (r = 0.92), indicating test reliability. The pack test performance was correlated to the fireline test (r = -0.79) and pulldown (r = -0.72). The fireline test was correlated to the pulldown test (r = -0.73), the pushup test (r = -0.70), and VO2 max (r = -0.56). Multiple regression analysis of the pack test and pushups yielded R = 0.862 (R2 = 0.743). Results indicate that both the pack test and the fireline test are valid and job related, but the pack test has lower administrative costs and less potential for adverse impact to women.

Development and validation of a work capacity test for wildland firefighters, DeLorenzo-Green, T. and Sharkey, B., Medicine and Science in Sports and Exercise. 27: S166, 1995.

This 1996 study was the final phase in developing a job-related work capacity test for wildland firefighters. This 1996 study related the candidate pack test to field performance and measures of aerobic and muscular fitness, and evaluated the potential for adverse impact to women. Ten male and ten female volunteers (ages 21 to 40) performed strength and VO2 max tests, 4.83-kilometer (3-mile) hikes with a 20.5-kilogram (45-pound) pack on both a level and a hilly course (including a 0.23-mile stretch with a 17.5-percent grade), and a 15-minute simulated fireline construction test.

Males and females did not differ significantly on the pack test (average score of 39.2 minutes for males compared to 42.4 minutes for females). Times for the flat and hilly versions of the pack test for males and combined (male and female) subjects were not significantly different, but were for females (2.56-minute difference, p < 0.01). The flat and hilly versions of the test were significantly related (r = 0.87). They were correlated to strength measures, and to the fireline test (table 4). The results confirm the relationship of the pack test to field performance, and to measures of aerobic and muscular fitness. Regression analysis indicated that a score of 45 minutes for the 3-mile pack test predicts a VO2 max of 45 milliliters/kilogram-minute, the current standard for wildland firefighters. A field evaluation of 320 firefighters (including 69 females) did not reveal evidence of adverse impact to women.

Validation and field evaluation of a work capacity test for wildland firefighters. Sharkey, B., Rothwell, T. and Jukkala, A., Medicine and Science in Sports and Exercise. 28: S79, 1996.

Aerobic Fitness

This study of 67 men and women confirmed the correlation between the pack test and aerobic fitness (max VO2). A score of 45 minutes on the pack test is equivalent to a VO2 of 45 milliliters/kilogram-minute.

Analysis of predictive tests of aerobic fitness for wildland firefighters. Strickland, M., and Petersen, S., Canadian Society for Exercise Physiology. 1999 (reported in Wildland Firefighters Health and Safety, No. 2, 0051-2855-MTDC).

Escape

This study showed that a higher level of fitness is associated with faster travel to a safety zone; that dropping the pack reduced transit time 21.5 to 26 percent; and that the energy demands of evacuation can equal or exceed the minimal aerobic fitness level required of wildland firefighters (45 milliliters/kilogram-minute).

Wildland firefighter load carriage: effects on transit time and physiological responses during simulated escape route evacuation. Ruby, B., et al., International Association of Wildland Fire. 2000 (reported in Wildland Firefighter Health and Safety: No. 2, 0051-2855-MTDC).