At Cardio Fit Sports Club, a sea of free weights floods the weight room, where strength-training machines, elliptical units, treadmills, and cardio machines also beckon visitors to work toward their dream bodies. Experienced trainers draw upon experience in martial arts and other disciplines while leading workout classes targeted at certain muscle groups. The instructors also design courses according to the needs of seniors, cheerleaders, recent mothers, or guys who have to pick up all the anvils and pianos at cartoon crime scenes. The driving rumble of high-energy bass lines drifts from Zumba sessions, and relaxed sighs waft from a yoga room. At select hours, clients can even take advantage of complimentary childcare to enjoy workouts alone.