Background: Working within the military as a ground combat solider is very physically demanding. Soldiers are required to handle situations ranging from peacekeeping to counterinsurgency and combat, while faced with the task of load carriage either in form of the military gear or other additional loads. Therefore, a good aerobic and anaerobic fitness is necessary. The aerobic and anaerobic fitness can be assessed with a wide range is methods such as measuring the peak oxygen uptake (VO2peak), ventilator threshold, blood lactate concentration and heart rate. However research is rather spares regarding the effects of load carriage on the aerobic capacity.

Aim: The aim of the current study was to investigate if military gear affects VO2peak, ventilatory threshold, blood lactate concentration and heart rate in ground combat soldiers.

Methods: A total of eight soldiers (seven men and one woman) participated in the current study. All participants completed two biological calibrations and VO2max tests (one without and one with military gear) using a modified Bruce protocol, where VO2 (L/min), absolute and relative VO2peck (L/min and ml/kg/min respectively), heart rate (beats/min) and blood lactate concentration (mM/L) were assessed. After the completion of the tests, the soldier’s individual ventilatory threshold (VT) was visually located using the V-slope method. The Wilcoxon test was used for the not normally distributed variables (blood lactate concentration and stage when VT occurred) and the paired sample t-test for the others. The significance level was set to 0.05.

Results: The results showed that the soldier had 10.6 % lower absolute VO2peak and 23.7 % lower relative VO2peak while wearing military gear compared to without (p=0.002 and p=0.001 respectively). The soldiers also had 11.8 % higher VO2 at VT with military gear (p=0.003) and reached a higher percentage of the VO2peak (p=0.023) at VT. The blood lactate concentration was significantly higher when marching at 5.4 km/h and a trend of a higher blood lactate concentration while standing was observed without military gear compared to with military gear.

Conclusion: The findings from the present study shows that performing load carriage in form of the military gear significantly decreased the VO2peak. Wearing a military gear also increased the VO2 at the individual VT and made the soldier reach a higher percentage of the VO2peak at VT. These results can act as guidance when recruiting and training soldiers, along with providing important information to other professions and sports that involve load carriage.