Metabolic Cost of Load Carriage in a Special Forces Team – A Non-parametric Approach

Military missions are often comprised of heavy load carriage whilst marching in difficult terrains. Furthermore, the ability of carrying a load is a fundamental requirement for successful missions and safety in these populations. The aim of the present study was to quantify the metabolic cost of load carriage in a Portuguese special forces team. Ten active-duty military personnel of a special forces team performed a graded protocol of until exhaustion on a treadmill in a thermoneutral environment in two different conditions: Unloaded and Fully loaded for combat. Using non-parametric statistical methods for hypothesis testing development, considering the Wilcoxon Test to compare two groups and Kruskal-Wallis test for analysing the differences by step in the different variables, with multiple pairwise comparisons, the study is performed in two main phases. First, considering the Unloaded and Fully loaded groups, it was analysed if it provided different results of peak oxygen uptake, heart rate and blood Lactate. Second, taking into account that higher differences were detected across categories (steps), we are interested in conducting an analysis which enables the definition of the ventilatory threshold and peak oxygen uptake for each condition. The fully loaded for combat condition showed higher values of oxygen consumption and heart rate in all steps of the exercise when compared to the unloaded condition. Peak oxygen uptake and heart rate were significantly different between the two conditions. This study enables to enhance our understanding of the metabolic cost of load carriage, in a special forces team, and its impact in military readiness.