The effect of single- or multiple-layered garments on interface pressure measured at the backpack-shoulder interface.

Experiments were aimed at determining whether interface pressure measurements are a true reflection of skin contact pressure when made over different layers of clothing. Interface pressures were recorded at the skin interface and above clothing layers, with 11 participants wearing 10 different clothing combinations. The clothing used was standard issue British military clothing, including body armour (without ballistic plate). Participants wore both single and multiple clothing layers whilst walking on a treadmill carrying a loaded backpack (23.5 kg, British military issue). Results showed no significant differences (p=>0.05) in pressure between different clothing layers either singly, or worn in multiple. In conclusion, the soldier (or leisure user) will gain no or very little relief from applied pressure by wearing garments, even in layers, when carrying a backpack. Also, the findings suggest that interface pressure may adequately be assessed using a sensor placed above the clothing layer(s) rather than at skin surface.