Altra Zero Drop is a new brand of running shoes with a serious passion for reinventing the running shoe. Their design ideas are smart, fresh, and have resulted in the most effective running shoe I've ever worn. The male-specific Instinct is their core training shoe, reviewed here along with its female-specific counterpart, the Intuition. The shoes take many of the concepts of so-called barefoot running and put them into a practical package that will actually work for those of us who haven't grown up with calloused soles. If you're in the market for new kicks, they're definitely worth a look.