Friction in your footwear can lead to blisters, and later, infections. In adventure racing, you're on your feet for hours, if not days. A product like Hydropel, a greasy salve made by Genesis Pharmaceutical Inc., is 100 percent requisite for many racers. Before you leave the starting line, slather the translucent goo between each toe and on your heals. Now pull your sock on. The lube keeps blisters at bay by making your skin slippery and friction-adverse. Available on Amazon for a hefty $19 for a two-ounce bottle.