Enrgi Fitness, Chicago

At ENRGi Fitness, the main regimen is a three-step process: workout, recover, and repeat. And clients have been working out, recovering, and repeating since 2009, when founder Amy Lee launched ENRGi Fitness under its original name, TEAMiFIT, as a series of outdoor boot camps taking place at numerous Chicago parks. Today, ENRGi Fitness teaches several different formats of high-intensity, strength and conditioning, and yoga and dance classes to more than 500 clients seeking to burn calories and build muscle. Warrior, for instance, is a circuit-style, strength and cardio workout that utilizes a variety of training aids like weights, kettlebells, and treadmills, and ends with a five-minute cool-down of stretching and flexibility.