The purpose of this study was to determine the effects of two leather (L1, L2) and two rubber (R1, R2) boots on firefighters' metabolic and respiratory variables during simulated firefighting tasks. Twenty-five men and 25 women, while wearing full turnout clothing, a 10.5-kg backpack, gloves, helmet, and one of four randomly assigned pairs of firefighter boots, walked for 6 min at 3 mph (4.8 km/hr) on a level treadmill while carrying a 9.5-kg hose and climbed a stair ergometer for 6 min at 45 steps per min without the hose. Minute ventilation (VE), absolute and relative oxygen consumption (VO2 and VO2 ml.kg.min-1, respectively), CO2 production (VCO2), heart rate (HR), and peak inspiratory (PIF) and expiratory (PEF) flow rates were measured, and an average of the breath-by-breath data from minute 6 was used for analysis. During treadmill exercise, a 1-kg increase in boot weight caused significant (p < 0.05) increases in E (9%), (5 - 6%), VCO2 (8%), and HR (6%) for men, whereas a 1-kg increase caused significant increases in (3 - 4.5%) and VCO2 (4%) for women. During stair ergometry, a 1-kg increase in boot weight caused significant increases in E (approximately 3%), relative VO2 (approximately 2%), VCO2 (3%), and PIF (approximately 4%) in men and women (p < 0.05) and a significant increase in absolute (approximately 3.5%) in men only. Mean increases in metabolic and respiratory variables per 1-kg increase in boot weight were in the 5 to 12% range observed previously for men during treadmill walking but were considerably smaller for women. Mean increases in oxygen consumption during stair ergometry were statistically significant but were smaller in the current study than previously observed and may not be practically significant. There was no significant effect of boot design in addition to boot weight for either mode of exercise.
Human-factors-engineering; Injuries; Injury-prevention; Muscle-function; Musculoskeletal-system; Biomechanical-engineering; Biomechanics; Exposure-assessment; Fire-fighters; Fire-fighting-equipment; Personal-protective-equipment; Physiological-factors; Physiological-fatigue; Physiological-measurements; Physiological-response; Physiological-stress; Weight-factors
Nina L. Turner, National Institute for Occupational Safety and Health, National Personal Protective Technology Laboratory, P.O. Box 18070, Cochrans Mill Road, Pittsburgh, PA 15236