We're all about minimalism when we're working out in the open air, but we also know that it's important to stay safe and supplied! Instead of a full-on gym bag, opt for a slender, lightweight waistpack (yes, the 2014 cousin of the retro Fanny pack) that securely carries essentials like I.D, keys, cash, or small snacks mile after mile without getting in the way. Go for a waistpack like this one from Nike, which has structured side webbing and a padded back panel keep it close and reduce any potentially annoying bounce.