Firefighting is an inherently dangerous occupation in which intrinsic hazards such as fatigue from physical exertion as well as extrinsic obstacles are commonly encountered. These hazards can lead to slip, trip, and fall (STF) related injuries, which constitute a large portion of annual severe firefighting injuries. The key objective of this work was to assess firefighters’ risk of STF injuries by observing performance when crossing a stationary obstacle. Two studies were carried out to accomplish this goal.
The first of these studies examined the effects of fatigue induced by several different simulated firefighting exercise protocols, as well as the carriage of a unilateral hose load when traversing the obstacle. Three simulated firefighting protocols were implemented, with each intended to replicate the environmental conditions and required workload of actual firefighting. To examine changes in movement behavior as a result of the fatigue induced by each condition, firefighters completed a functional task course which included traversing a stationary obstacle both before and immediately after each protocol. In half of the trials, subjects carried a hose pack unilaterally. Obstacle contact errors and both horizontal and vertical clearances of each foot over the obstacle were measured. Significant changes were observed as a result of fatigue, unilateral load carriage, and protocol. The results of this study can help to develop a standard for simulated firefighting, and may ultimately help lead to a reduction in slip, trip, and fall injuries by providing a better understanding of how fatigue and load carriage can impact movement behavior on the fireground.
The second study examined the effects of different sizes and designs of SCBA as well as the fatigue effects of extended duration firefighting on obstacle crossing ability. Larger capacity SCBA cylinders are becoming more widely available, allowing for longer periods of continuous firefighting. Furthermore, novel SCBA pack designs beyond traditional cylinder geometries are being developed to improve biomechanical compatibility. To assess biomechanical changes induced by these factors, firefighters again completed the functional task course including crossing a stationary obstacle both before and immediately after undergoing one of three simulated firefighting protocols and using varying types of SCBA. Obstacle contact errors, obstacle clearances, and peak normalized ground reaction forces (GRFs) were measured. For this study, several clearance metrics which had not been widely utilized previously were implemented and compared to the more common horizontal and vertical clearance metric. Few effects of SCBA size or design were observed, while effects of fatigue and exercise protocol were more apparent. The new clearance metrics were also observed to be more sensitive in detecting statistically significant changes than the more common clearance metrics. The results suggested that the effects of SCBA size and design on obstacle crossing ability are minimal, while fatigue – particularly that induced by extended duration firefighting, regardless of rehabilitation – increases the risk of STF injury. These results also suggest that the use of the new clearance metrics can provide useful information on changes in obstacle crossing behavior which may not be apparent from the commonly utilized metrics. These results may provide a better understanding of how equipment and varying degrees of fatigue contribute to the risk of STFs and their associated injuries, and may assist fire departments in making informed decisions when outfitting their firefighters
