Clanging weights and whirring bikes have unendingly echoed throughout Kraze Fitness since 1998, when the 24-hour gym first opened its doors as 24/7 Fitness. With the help of the facility’s ultramodern fitness and strength-training equipment, the personal trainers enthusiastically motivate clients to drop pounds and lead healthier lifestyles without the hassle of transplanting their brains into fitter bodies. The club is run by an MMA black belt, who shows his stuff in martial-arts classes for youths and adults. Intense cross-training sessions incorporate Olympic weightlifting, gymnastics, and kettlebell drills, and rhythmic Latin beats underscore energetic Zumba classes, providing an upbeat alternative to meditative yoga classes and cathartic kickboxing sessions.