What New Research Says About Circuit Training—and Why It Matters for Busy Adults Most people believe that if you want to get stronger, build muscle, and improve your fitness, you need long workouts and lots of rest between sets. The traditional model looks something like this: Lift a weight Rest for three minutes Lift again Rest again Repeat that for an hour and a half. That approach works—especially for competitive powerlifters—but it’s not always realistic for busy adults b