It’s just after 6 p.m. at Grady Park, and that sound is back. It starts as a quiet wheezing, slowly growing into a chorus of huffs, puffs, and the occasional groan. These guttural sounds aren’t coming from a wild beast or a meeting of Big Bad Wolves Anonymous—they’re coming from a trove of men and women sprinting, lunging, and jumping through Silverback Elite Fitness Boot Camp's intensive exercises. Twice per week, campers follow their faithful instructors through Grady Park and around McWhirter Elementary, dropping to the ground for a set of pushups or scooping a pair of dumbbells off the ground. The one-hour workout leaves campers’ hearts pounding, limbs shaking, and muscles burning; yet, within a matter of days, they’ll each return for another round, with a renewed sense of fitness and increased capacity to handle the grunt-inducing workouts.