Conference abstract:
Introduction
Firefighting imposes high physiological and psychological strains. This is due to the variety of physically demanding tasks firefighters perform at an emergency scene as well as high ambient temperatures and wearing protection gears. However, most studies investigated simulated task-testing in absence of environmental stressors such as high ambient temperatures in order to determine the physical loads of firefighting. Moreover, firefighter’s responses to suddenly occurring dangerous situations such as a flashover have not been established yet. A flashover describes the phenomenon where a fire reaches its ignition temperature and spreads quickly due to inflammable gases emitting from materials and exposed surfaces in an enclosed area. This dangerous situation is explicitly trained by firefighters in a burning container that simulates flashovers. The aim of this research was to examine the contribution of aerobic and anaerobic energy systems to the physical performance of German firefighters in a flashover training.
Methods
Sixteen professional firefighters (age 38.9 ± 8.9 yr, height 177.3 ± 6.9 cm, weight 81.5 ± 9.3 kg) performed firefighting tasks with a simulation of the flashover phenomenon in a container. In advance, a treadmill test in order to establish peak oxygen uptake (VO2peak), ventilatory threshold (VT1) and respiratory compensation point (RCP) was done under laboratory conditions. Three intensity zones were identified according to the HR values corresponding to VT1 and RCP.
Simulated task-testing included ladder climb, hose advance and extinguishing different kinds of fires across the enclosed area of the training container. Subjects wore full protective clothing (24.5kg) and a self-contained breathing apparatus for air supply. Heart rate (HR) and depletion of air supply were measured during the drill.
Results
Mean time to complete the training was 16.1 ± 1.7 min with a mean heart rate of 147.8 ± 12.4 bpm across 16 subjects. The depletion of air supply averaged 140.7 ± 20.3 bar. According to preliminary data of 6 firefighters, subjects spent 18.9 ± 11.0 % of training-time below VT1, 66.6 ± 8.0 % of time between VT1 and RCP and 13.9 ± 12.6 % of time above RCP. These subjects performed the training with a mean percentage of 81.7% of maximal HR.
Discussion
According to our results, the highest energy contribution during a flashover training comes from the aerobic-anaerobic system (time spent between VT1 and RCP). Moreover, we found evidence for a high contribution of the anaerobic system in the second half of the flashover drill. Subjects with a higher VO2peak in relation to age were able to supply a greater percentage of the total energy demand aerobically resulting in less physiological strain. Our results demonstrate the importance of an appropriate training level for professional firefighters.
Inwinkl S. *, Seiberl W. *, Schwirtz A. *, Hahn D #.