The Cooper Institute

Founded in 1970 by the "Father of Aerobics"
Kenneth H. Cooper MD, MPH


Does circuit training prepare firefighters for the job?

Written by
Sue Beckham, PhD
Posted in
Move more

Monday, Nov 28, 2011

Firefighters face challenging physical stresses on the job. These include anaerobic activities which can produce significant levels of lactic acid (6-13 mmol/L)2 while also targeting the cardiovascular system requiring heart rates of 79-88% of maximum3,4. For this reason, circuit training where cardio and strength stations are alternated with short rest periods between is often a popular training option for firefighters to target both aerobic and anaerobic conditioning systems. But does circuit training stimulate aerobic and anaerobic energy systems enough to meet the demands of firefighting?

To answer this question, Mark Abel and his colleagues1 measured the heart rate response and anaerobic stress of circuit training and compared them to the levels required during firefighting activities. They recruited 20 firefighters to complete two rotations of a 12-station circuit comprised of resistance and cardiovascular exercises (stair climber or treadmill equipment), targeting all major muscle groups. Resistance training exercises included the lat pulldown, cable pulldown, seated row, leg press, shoulder press, deadlift, step-up, wood chop, push-ups, and one-arm cable pull. Firefighters selected a resistance that allowed them to perform 12 repetitions in 30 seconds for exercises performed on resistance equipment. Subjects performed as many repetitions as possible for body weight exercises. A 30-second recovery period was used between stations during which firefighters moved to the next station. The circuit lasted approximately 29 minutes. Average heart rate was measured during each of the circuit rotations to assess the aerobic intensity of circuit training. To determine anaerobic intensity, blood lactic acid levels were measured after the workout. 

Researchers reported that the anaerobic intensity of the circuit was similar to firefighting tasks. The average lactic acid level after exercise was 11.7 mmol/L which was within the 6-13 mmol/L range reported by other researchers2 during firefighting tasks. The aerobic intensity of the workout was 79% of age-predicted maximal heart rate. This is a lower average heart rate than reported,4 while performing 15 minutes of fire ground tasks (88% of maximum heart rate). However, it is consistent with average heart rates reported3 during less intense firefighting tasks such as 17 minutes of simulated smoke-diving (entry into a smoke filled room) operations in a heated simulator (79% of maximum). 

It is important to remember that heat, emotional stress, and dehydration can also increase heart rate. Therefore, it is difficult to tell how much of the heart rate measured during simulated fire activities is related to heat, hydration level, and stress and how much to the actual physical work required to perform the task. Also, researchers did not measure oxygen consumption which is a better indicator of physical stress than heart rate.

Based on the results of this recent study and others, Abel and his colleagues1 suggest that firefighter circuits include multi-joint functional exercises to further increase the heart rate response. They recommend using 5-15 functional exercises like the deadlift, wood chop, stair climb, mannequin drag, carrying 5 gallon cans of sand or water to simulate equipment carry, hitting a tire with a sledge hammer and kneeling fire hose pull. With regard to circuit design, they suggest 20-60 second stations with a 1:1 work:rest ratio between stations. Circuits should always include a warm-up, cool down, and static stretching after the workout.  

Circuit training can help firefighters improve aerobic and anaerobic fitness levels as well as muscular endurance. It is also a time- and space-efficient group exercise that can be used to encourage team work. Circuit training, however, should be part of an overall, progressive conditioning program that also targets muscular strength and power, in addition to sustained moderate- to high-intensity cardiovascular training. Firefighter fitness can be challenging and must address the variety of physical stresses firefighters face on the job. If you’re a firefighter, share some of your favorite exercises and workouts with us on Facebook.   

1Abel, M.G., Mortara, A.J. & Pettitt, R.W. (2011). Evaluation of circuit-training intensity for firefighters. Journal of Strength and Conditioning Research. 25(10), 2895-2901. 2Gledhill, N. & Jamnik, V.K. (1992). Characterization of the physical demands of firefighting. Canadian Journal of Sport Science. 17, 207-213. 3Lusa, S., Louhevaara, V., Smolander, J. et al. (1993). Physiological responses of firefighting students during simulated smoke-diving in the heat. American Industrial Hygiene Association. 54, 228-231. 4Sothmann, M.S., Saupe, K., Jasenof, D. & Blaney, J. (1992). Heart rate response of firefighters to actual emergencies: Implications for cardiorespiratory fitness. Journal of Occupational Medicine. 34, 797-800.