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Exercise physiologist to recommend tougher work capacity test for hot shots

The following article was contributed by Rae Brooks.

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Hotshots could face a tougher work-capacity test in the future, including carrying a heavier pack over hilly, instead of level, terrain and performing pushups to demonstrate upper-body strength.

Dr. Joe Domitrovich, an exercise physiologist at the U.S. Forest Service’s Missoula Technology & Development Center in Missoula, Mont., will recommend this summer to the U.S. Forest Service and other agencies that the work-capacity test for hotshot crews be upgraded.

“I don’t think I’ve had a hotshot tell me that they don’t agree with a fitness requirement that’s a little more strenuous,” said Domitrovich, himself a former hotshot. “They feel it will better prepare young firefighters for what the physiological demands of the job actually are.”

The new test would require a hotshot to carry a 55-pound pack over mountainous terrain in a time calibrated according to the elevation gain. Domitrovich hasn’t yet finalized the pushup requirement, but expects it will be “in the mid-teens.”

The current arduous pack test requires firefighters to walk a three-mile flat course, carrying a 45-pound pack, in 45 minutes or less. There is no pushup requirement.

Although more than 20 incident command positions currently require the arduous category test, the recommendation for the new test will apply only to hotshots. Hotshots already rank among the fittest people in the country, placing within the top 10 to 15 percent of national fitness norms. Some female hotshots rank in the top 5 percent.

Domitrovich’s recommendation grew out of a study, which began in 2011, designed to analyze the physiological job demands of firefighting. The Forest Service’s risk management group had asked the Missoula researchers to look at the fitness demands of firefighting and perhaps recommend a new work-capacity test since the research to develop the current pack test was two decades old.

Earlier studies had only looked at the energy costs of the entire firefighting shift. With better technology, Domitrovich and his collaborators are able to track the physiological cost of individual tasks, including the morning hike into the fireline, line construction and mop up.

The researchers first contacted hotshot crews across the country to ask about the frequency and difficulty of their various tasks — including packing heavy loads, building line, and chainsawing, often performed in hot, smoky conditions. In 2011, they performed physical fitness laboratory tests at the University of Montana on hotshot crews from the Missoula area to establish baseline fitness levels.

Chest harness
The chest harness that the study subjects wore that held the receiver that collected data from the transmitter they swallowed. USFS photo.

For the past two fire seasons, researchers have been collecting data from firefighters at large fires in many states. Field staff are detailed from hotshot, helitack and rappelling crews and from various ranger districts. Before heading out for their shifts, volunteers swallow tiny single-use capsules the size of a multi-vitamin pill that measure internal body temperature. The body-temperature data is sent wirelessly to a chest harness, which has sensors to record heart rate, respiration rate and skin temperature. Domitrovich calls it “a heart-rate monitor on steroids.” Portable GPS units worn by the firefighters track speed, grade and elevation. “We can get a real good idea of what they’re doing out there,” he said.

Data has now been collected from more than 100 firefighters at fires in New Mexico, Arizona, Colorado, California, Oregon and Washington. This season, the researchers plan to work at fires in the Southwest and also collect data from initial attack crews. Logistics make collecting data from smokejumpers and rappelling crews more challenging.

“We try not to disrupt normal operations for the crew,” said Domitrovich. The volunteers report to the researchers’ trailer about 45 minutes before the crew goes to breakfast. The researchers have had no problem recruiting volunteers. “Most people want to volunteer because they see the benefit of having us out there collecting data,” said Domitrovich. “Not just for themselves, but for their wildland firefighting crew and future firefighters that maybe aren’t even on the job yet.”

Not surprisingly, the morning hike into the fireline, carrying tools and other gear, was the most demanding — and most common — firefighting task. Measured by oxygen demand, the daily hike was almost twice as tough as the arduous pack test. The souped-up heart-rate monitor and its connected technology revealed that, during the daily hike to the work site, firefighters used an average of 42.3 milliliters of oxygen per kilogram of body weight per minute. Aerobic demand while undergoing the arduous pack test has averaged 22.5 ml/kg/min.

The conclusion: the arduous pack test wasn’t actually arduous enough. Carrying more weight and performing the pack test in mountainous terrain would better mimic job demands.

Researchers weighed volunteers’ packs, and found they were carrying 45 or 50 pounds — regardless of body weight, height or gender — before even adding tools, extra fuel or five-gallon water cubies. “Fifty-five pounds is closer to what they’re actually carrying out there,” said Domitrovich.

Because hotshots usually work in nasty terrain, switching the pack test to mountainous terrain would also better duplicate job conditions. As a hotshot, when Domitrovich fought fire on flat terrain, he knew he was in for a fun day — “because it was an easy day,” he said.

The average elevation of proposed mountainous courses will be calculated using GPS devices. A chart will show time standards for various elevation gains. The chart was developed by Domitrovich and his colleagues by having 45 volunteers of different sizes and genders hike with a 55-pound pack in the hills around Missoula at varying speeds, grades and elevations. “As elevation gets steeper, you get more time,” he said.

Besides push-ups, the researchers considered adding sit-ups and planks to the new test. Sit-ups were rejected because they are an imperfect measure of abdominal strength. Planks, which test core strength, were deemed a duplication since carrying a 55-pound pack also requires core strength.

Domitrovich will present his recommendation this summer to the U.S. Forest Service risk management council and to the National Wildfire Coordinating Group’s risk management committee. If the recommendation is accepted, a date for implementation of the new test would then be determined.

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(UPDATE from Bill, June 9, 2015: we just posted an article about the fitness test for Canadian wildland firefighters, WFX-FIT, that is very different from either the current or proposed Work Capacity Tests for U.S. firefighters described above.)

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