Further Fitness trainers Jamie Dreyer and Maribel Torres have made it their mission to "dispel . . . myths and old-wives tales" about fitness. Inspired by their backgrounds in youth sports, exercise-science studies, and a chance encounter with fitness godfather Jack LaLanne, they have created an effective, challenging, and exciting program focused on the fundamentals of boosting metabolisms and muscle mass. Their stripped-down studio builds bodies with simple tools, such as kettlebells, battling ropes, and sandbags. To stimulate the cardiovascular system, Jamie and Maribel might have students haul a weight sled and pull in equal amounts of physiology and anatomy knowledge. Sessions are held in semiprivate and group settings, and an athletic-strength program devotes itself exclusively to training high-school-level athletes and any toddlers that can run a decent 40-yard dash or live in the requisite angst in which high schoolers often live.