Physiological stress in flat and uphill walking with different backpack loads in professional mountain rescue crews.

Abstract

[EN] This study aimed to determine the interactive physiological effect of backpack load carriage and slope during walking in professional mountain rescuers. Sixteen mountain rescuers walked on a treadmill at 3.6km/h for 5min in each combination of three slopes (1%, 10%, 20%) and five backpack loads (0%, 10%, 20%, 30%, and 40% body weight). Relative heart rate (%HRmax), relative oxygen consumption (%VO2max), and rating of perceived exertion (RPE, Borg 1-10 scale) were compared across conditions using two-way ANOVA. Significant differences in %VO2max, %HRmax, and RPE across slopes and loads were found where burden increased directly with slope and load (main effect of slope, p<0.001 for all; main effect of load, p<0.001 for all). Additionally, significant slope by load interactions were found for all parameters, indicating an additive effect (p<0.001 for all). Mountain rescuers should consider the physiological interaction between slope and load when determining safe occupational walking capacity.