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Technology &
Development Center
Wildland Firefighter Health and Safety
Recommendations of the April 1999 Conference

Demands of the Job

Brian J. Sharkey, Ph.D.
USDA Forest Service
Missoula Technology & Development Center

“That a man must be physically sound for his work we know, but a standard of soundness has never been defined . . it is urgent that a simple but effective method be used by all employing officers to insure the rejection of the clearly unfit.”
Coert Dubois, USDA Forest Service, Southwestern Region (R5), 1914

This paper reviews the determination of job demands and the development and validation of a job-related work capacity test for wildland firefighting. It will also identify other job-related issues that may impact the health and safety of wildland firefighters.


In 1965 The Missoula Equipment Development Center (now the Missoula Technology and Development Center), and cooperators from the University of Montana Human Performance Laboratory began work on a test to determine a candidate’s fitness to perform arduous wildland firefighting tasks. Field measurements of the metabolic, cardiovascular, and thermal demands of firefighting tasks were made on firefighters working on controlled (prescribed) burns. The results indicated that wildland firefighting tasks fell into the category of hard work, with average energy expenditures of 7.5 kcal/min. Based on these measurements and a review of the literature, it was concluded that (for the firefighters then employed) aerobic fitness (max VO2) was the primary limiting factor in the firefighters’ ability to sustain hard work throughout long work shifts.

The Astrand-Rhyming Step Test was modified, validated, field tested, approved by the Civil Service Commission (now the Office of Personnel Management), and adopted in 1975 as the test to determine firefighter fitness for duty. Since workers cannot sustain day-long workloads above 50% of their maximum capacity, the average energy cost of firefighting duties (22.5 ml/kg.min) was doubled to determine the minimum score (45 ml/kg.min) for wildland firefighters. Soon after the test procedure was implemented, concerns arose that some workers lacked the muscular strength to do the job. These concerns coincided with the integration of women into the wildland firefighting workforce. Field studies of muscular fitness and work capacity (Sharkey, Jukkala, Putnam, and Tietz 1980) confirmed the relationship of strength and lean body weight to performance in firefighting (the average female has 50 to 60% of the upper body strength of male workers). Recommendations to add muscular fitness measures to the selection process were not adopted. The Step Test (and alternative 1.5-mile run) remained the measures used in the selection of firefighters.

In 1994 MTDC was assigned to review test procedures and revise training materials to ensure compliance with new laws, regulations, and recent research. MTDC conducted an extensive review of the scientific literature and legal precedents related to employee selection, and surveyed field comments to determine worker satisfaction with the existing tests. Research, new laws, and field responses all called for revision of the fitness tests. The Step Test violated the American’s with Disabilities Act (use of biomedical data; specifically the heart rate: Equal Employment Opportunity Commission EEOC #915.002, 5/94), the test was not directly job related, and there was evidence of cheating (use of drugs to lower the heart rate). Workers were dissatisfied with the test and eager for a change. MTDC undertook a revision of the wildland firefighter Job Task Analysis, and then conducted a series of laboratory and field studies on the development and validation of a job-related work capacity test.

Job Task Analysis

The Job Task Analysis was conducted with input from National Wildfire Coordinating Group (NWCG) member agencies and some States. Respondents rated the importance as well as the intensity, duration, and frequency of tasks. New categories in the revised analysis included:

The analysis indicated that the most important firefighting tasks included:

Tasks receiving lower ratings, primarily because they occurred less frequently included:

Wildland firefighting clearly deserves the definition of arduous work:

“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 of time. 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.” (NWCG 310.1)

Job-Related Work Capacity Tests

The test development and validation process followed the Federal Uniform Guidelines for Employee Selection Procedures. MTDC used the job task analysis and data from past field studies to identify potential tests. Based on high correlation to other firefighting tasks, a fireline construction (Pulaski Test, upper body) and a load carry (Pack Test, lower body) were the tests best correlated with performance. They were selected for further laboratory and field evaluation.

Laboratory Studies

The Fireline Test and Pack Test were found to have energy costs similar to those required on the job (7.5 kcal/min). Both tests were significantly correlated to laboratory measures of aerobic and muscular fitness, and to performance on firefighting tasks. And both were judged to be valid, reliable, objective, and job-related measures of work capacity. However, because of its reliance on upper body strength, the Fireline Test was found to have adverse impact on females (based on the EEOC 80% rule; females passed at less than 80% of the males’ pass rate). Moreover, the Fireline Test requires a higher administrative cost (test equipment, time). The Pack Test uses available equipment and does not show evidence of adverse impact. The flat version of the test is highly related to performance on a hilly course (r = 0.87, although the hilly course had an adverse impact on female candidates). A score of 45 minutes on the Pack Test approximates a score of 45 on the Step Test (the current standard for wildland firefighters). Based on these studies (Sharkey, Rothwell, and DeLorenzo-Green 1994; DeLorenzo-Green and Sharkey 1995) the Pack Test was scheduled for field trials.

Pack Test Field Trials

During the 1995 fire season, field trials were conducted on 320 firefighters from three regions of the Forest Service, three federal agencies, and one State. The sample represented the gender and ethnic distribution of the firefighter population (Sharkey, Rothwell, and Jukkala 1996). Ethnicity did not appear to be a factor in test performance. For a passing score of 45 minutes, males passed at the rate of 84.4% vs 71.9% for females. Thus females passed at 85.2% of the male pass rate, which does not constitute adverse impact as defined by the EEOC. The field trial was not a condition of hire, so some subjects did not give their best effort. Also, field experience has shown that subjects improve substantially when retested, so those within 1 minute of the passing score would be likely to pass on a retest (89.5% of the males and 79.7% of the females were under 46 minutes, yielding a female/male pass rate of 89%). The scores were also analyzed for the effects of age, height, and weight.


Subjects ranged from 18 to 63 years old, and included 30 subjects over 40 years old. Those over 40 years averaged 41.4 minutes on the Pack Test, a score that was superior to the overall average (41.8 minutes). Of the 30 subjects over 40 years of age, 5 scored over 45 minutes and 25 under 45 minutes, for a pass rate of 83.3%. This pass rate exceeds the pass rate for all subjects (81.9%).


Heights ranged from 61 to 79 inches with an average of 69.7 inches for all subjects (70.6 inches for males and 66.3 inches for females). While the data for all subjects suggested a relationship between height and performance on the Pack Test (r = -0.294), analysis of scores above 45 minutes revealed no significant relationship (r = -0.022. r2 = 0.0005). The correlation squared (r2) indicates the proportion of the variance in performance accounted for by a relationship. Far less than 1% (0.05%) of the variation in performance among test scores over 45 minutes can be attributed to height.

A 1998 field evaluation of over 5,000 firefighters verified the results of the 1996 field trial. However, it identified a somewhat lower pass rate for 101 individuals under 5 feet 3 inches in height. Subsequent analysis of the 33 who did not pass indicated that 18 did not finish, 10 were overweight, several were underweight, 9 did no training, and 27 completed less than 12 hours of training for the test. The results suggested that those factors and the low lean body weight associated with short stature contributed to the somewhat lower pass rate.


Weights ranged from 104 to 270 pounds, and averaged 170.9 pounds for all subjects (178.7 pounds for males, and 140.9 pounds for females). There was no relationship between weight and performance on the Pack Test for all subjects, by gender, or for those who scored over 45 minutes.

Pack Test Summary and Recommendations

The Pack Test is a valid, job-related test of work capacity. The test uses a firefighting tool (pack) and requires an energy cost similar to that demanded on the job. Pack Test scores are correlated to laboratory measures of fitness, and to performance of the firefighting tasks identified in the job task analysis. The duration of the test ensures the capacity to perform prolonged arduous work, under adverse conditions, with a reserve to carry out emergency responses. Pack Test scores are not adversely influenced by gender, ethnicity, age, height, or weight.


Testing and Training

Health Screening

The American Heart Association (AHA) and the American College of Sports Medicine (ACSM) recommend a medical examination for persons over 45 years old, for those with heart disease risk factors, and for individuals who have been sedentary before a major increase in activity. For many others, a simple health screening questionnaire provides assurance of the readiness to engage in training, work, or a job-related work capacity test.


Par-Q is a health screening questionnaire designed to identify that small number of individuals who should seek medical advice concerning involvement in moderate activity (exercise intense enough to result in fatigue within 20 minutes). A “no” answer to seven simple health questions indicates suitability for involvement in an exercise test or moderately vigorous aerobic and muscular fitness training. The revised PAR-Q questionnaire was developed and validated by the Canadian Society for Exercise Physiology. Use of the questionnaire substantially reduces the risk of taking exercise tests or training for apparently healthy adults. Candidates for fitness training, firefighting, and field work should complete PAR-Q screening before taking a work capacity test or beginning strenuous training. An alternative one page screening form may be found in the 1998 AHA/ACSM recommendation. The recommendation raises the age for more intensive screening from 40 to 45 years old.

Persons Over 45 Years Old

A physician may recommend an electrocardiogram-monitored exercise test for individuals over 45 years old, with one or more heart disease risk factors (such as smoking, high blood pressure, or elevated cholesterol), for those who have been inactive, or for those whom the test, training, or work represent a significant increase in exercise intensity.

Medical Examinations

Wildland Firefighter Health and Safety Conference participants discussed the need for more extensive health screening, physician examinations, and medical tests for wildland firefighters. Federal agencies are currently considering a comprehensive medical history, medical tests, and physician examination for entry-level firefighters. The medical history would be updated annually, and the physician examination and some medical tests would be repeated every 5 years under the current proposal. Costs include several hundred dollars per candidate for medical tests and physician examinations. Benefits could include early detection of health problems, some reduction in Occupational Workers Compensation Program costs, and assignment of candidates to more appropriate positions, when possible. Problems include the waste of scarce resources on a predominately young, generally healthy population, false positive results (indication of a problem that may not exist), and the costs of additional testing needed to clear candidates for work. Alternatives to comprehensive examinations include risk stratification by low-cost screening (such as the PAR-Q questionnaire) or a more comprehensive medical history, with tests and examinations for those at higher risk (for instance, those over 45 years old).

Training for the Pack Test

Before training, candidates should complete the PAR-Q questionnaire and see a physician if indicated. They should begin training at least 4 to 6 weeks before they report for duty. They can train by hiking or power walking, wearing the ankle-height footwear they will use during the test. Have candidates:

Job-Related Issues

Other job-related issues considered at the Wildland Firefighter Health and Safety Conference included:

With the increased use of firefighters for spring- and fall-burning programs, and the increasing severity and duration of fire seasons, seasonal exposure limits may have to be considered. Conference participants also considered alternatives to the 21-day assignment. In addition to issues of fatigue, nutrition, rest, and health (immune system), participants considered the effect of assignment or shift length changes on firefighter compensation. Suggested changes can be found in the Recommendations section of this publication.

Selected References

Balady, G.; Chaitman, B.; Driscoll, D. and others. Recommendations for cardiovascular screening, staffing, and emergency policies at health/fitness facilities, American Heart Association, 1998. Available at

De-Lorenzo-Green, T.; Sharkey, B. Development and Validation of a Work Capacity Test for Wildland Firefighters. Medicine and Science in Sport and Exercise, 1995.

This 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 7 female volunteers performed direct (treadmill) and indirect (step test) tests of maximal oxygen intake; muscular fitness tests (bench press, pull down, push up); a field Pack Test (PT) consisting of a 4.83 km (3 mile) hike over level terrain while wearing a 20.5 kg (45 lb) pack (performed w & w/o a respirator); and a five minute simulated fireline construction test (FT). Subjects also performed pack and line building trials to determine the energy cost of each activity. Results indicated that the energy cost of the PT at 4 mph was 22.2 ml/kg-min, which is similar to the documented cost of firefighting duties, including line construction (22 ml/kg-min). There was no significant difference between males and females on the PT, but there were differences between males and females on the FT (161 vs 109 ft; P < .013) and the muscular fitness tests (P < .0001). There was no significant difference in PT performance with or w/o a respirator, and the trials were highly related (r = .92) indicating test reliability. The PT performance was correlated to the FT (-.79) and pull down (-.72). The FT was correlated to the pull down (.73), the push up (.70), and VO2 max (.56). Results indicate that the PT and the FT are valid and job related, but the PT has lower administrative costs and less potential for adverse impact.

Department of Labor, Uniform Guidelines for Employee Selection. Federal Register, Aug. 25, 1979.

Sharkey, B.; Jukkala, A.; Putnam; S.; Tietz J. Validation: Muscular Fitness Tests, MTDC, 1980.

Sharkey, B.; Rothwell, T.; DeLorenzo-Green, T. Development of a Job-Related Work Capacity Test for Wildland Firefighters. Medicine and Science in Sport and Exercise, 1994.

Since 1975 Federal land management agencies have used a 5-minute step test to select wildland firefighters. New laws (ADA), field experience, and research concerning long-term work capacity have led to a re-examination of the selection procedure. This study is the initial step in the search for a new test. Eighteen volunteers (9 male, 9 female; 20-36 years old) performed direct and predicted leg tests of maximal oxygen intake, arm tests of peak VO2 and sustained (30 min) performance, a battery of muscular fitness tests, and a field (pack) test which consisted of a 4.83 km (3 mile) hike over level terrain while wearing a 20.5 (45 lb) 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 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 (49.4 - 43.4 ml/kg-min; P = .085; and 40.1 - 44.9 min; P = .059 respectively). The Pack Test was significantly related to the step test (r = -.455) and the leg VO2 max (-.579), and to muscular fitness measures, including leg press (-.553) and pull-ups (-.501). The Pack Test also correlated to arm peak VO2 (-.52), the arm VT (-.592), and the sustained arm endurance test (-.707). Multiple regression analysis of Pack Test performance vs. aerobic (arm and leg VO2 max, arm endurance, Pack Test lactate) and muscular (leg press, pull-ups) yielded R = .846. 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 approximates the current fitness requirement of 45 ml/kg-min.

Sharkey, B.; Rothwell, T.; Jukkala, A. Validation and Field Evaluation of a Work Capacity Test for Wildland Firefighters, Medicine and Science in Sport and Exercise, 1996.

This is the final phase in the development of a job-related work capacity test for wildland firefighters. This study related the candidate Pack Test to field performance and measures of aerobic and muscular fitness, and evaluated the potential for adverse impact. Ten male and 10 female volunteers (ages 21 - 40) performed strength and VO2 max tests, 4.83 km (3 mile) hikes with a 20.5 kg (45 lb) pack (PT) on both a level and a hill course (w 0.23 miles @ +17.5%), and a 15 min simulated fireline construction test (with handtool). Males and females did not differ significantly on the PT (39.2 vs 42.4 min respectively). Times for the flat and hill versions of the PT for males and combined (male/female) subjects were not significantly different, but were for females (dif = 2.56 min, p < .01). The flat and hill versions of the test were significantly related (r = .87). They were correlated to strength measures (pull-up, r = -.61 & .67; push-up = -.68 & .67), VO2 max (r = -.77 & .65), and the fireline test (r = -.50 & -.60) for flat and hill tests respectively. The results confirm the relationship of the PT to field performance (hill course, fireline test), and to measures of strength and aerobic fitness. Regression analysis indicated that a score of 45 min for the 3 mile Pack Test approximates a VO2 max of 45 ml/kg-min, the current standard. A field evaluation of 320 incumbent firefighters (69 females) did not reveal evidence of adverse impact.

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