Physiological, perceptual, and biomechanical responses to load carriage while walking at military-relevant speeds and loads: are there differences between males and females?

This study aimed to investigate the physiological, perceptual, and biomechanical differences between male and female soldiers across several military-relevant load and walking speed combinations. Eleven female and twelve male soldiers completed twelve 12 min walking trials at varying speeds (3.5 km·h−1, 5.5 km·h−1, 6.5 km·h−1) and with varying external loads (7.2 kg, 23.2 kg, 35.2 kg). Physiological (indirect calorimetry, heart rate), perceptual (perceived exertion), and biomechanical (spatiotemporal, kinematic, kinetic) outcomes were measured throughout each trial. Females had a lower aerobic capacity and lower body strength than males, which resulted in them working at a greater exercise intensity (%VO2peak and heart rate) but with a lower oxygen pulse. Females demonstrated higher breathing frequency and perceived exertion with specific loads. At selected loads and speeds, frontal and sagittal pelvis, hip, and knee motions and forces were greater for females. Females consistently displayed greater relative stride length and step width. In conclusion, this study demonstrates the importance of tailored interventions, periodisation, and nutritional strategies for female military personnel, given their higher relative work rate and increased injury risk during load carriage tasks. Understanding these differences is crucial for preparing female soldiers for the physical demands of military service.