Soldiers are on their feet all day -- whether in the desert, the jungle, or even the snow. The loads they carry, their environment, and the speeds at which they move all impact their feet -- and the boots they're wearing. So engineers at an Army research lab in Natick, Massachusetts, are working to ensure that the boots on the ground work well and feel great. Footwear engineer Mike Holthe uses his training in biomechanics -- applying the principles of engineering to the human body -- to create and test boots. In the footwear lab, he measures the impact forces around a boot to test its performance before it's tested on real feet. His work has paid off by reducing soldiers' foot and leg injuries by more than 30 percent. "If we can make it so a soldier's not even thinking about their boots, then that's a victory," Holthe says. "It feels good to be able to hand a pair of boots to a soldier, have him try them on and smile."