Project Aquarius .9. Relative influence of job demands and personal factors on the energy expenditure, strain, and productivity of men suppressing wildland fires

Studies of hand-tool crews suppressing summer bushfires showed wide variations in firefighters' energy expenditure (EE) and productivity, and in their physiological and subjective responses ('strains'). Analyses of variance showed that (1) EE while using a rakehoe ('raking') varied mainly between subjects (i.e. with personal factors); (2) sweat rate, thigh skin temperature, and the proportion of the work time spent in each activity of fire suppression varied mainly between days of fireline construction (i.e. with job demands); and (3) heart rate, rectal temperature, perceived exertion, productivity, efficiency, and all-activities EE varied more or less equally between subjects and days, each of which explained about one third of the variation. These findings show that personal factors were no less influential than were the demands of the job.