justin steele

YES, YOU CAN work every muscle in your body with one piece of gear. We love kettlebells, med balls, and resistance bands, but if we had to choose one piece of equipment, it would be a single dumbbell.

The game plan: Three times a week, you’ll grab the simplest tool in the gym and use it to build muscle and banish fat in a super-dense half-hour workout. It’s the most effective way to fry body fat, and it’s the perfect way to train for the holidays. It’s also exactly how Hollywood-based trainer Ben Bruno, C.F.S.C., guides time-strapped A-listers like Justin Timberlake and NBA star Klay Thompson. “They want quick, efficient workouts that hit everything,” Bruno says. “So we need to move fast.”

It doesn’t get more efficient than this light-speed, one-dumbbell workout.

Circuit A

Do 4 rounds of this circuit.

1. Single-Arm Standing Shoulder Press

How to Do It:

Stand holding a dumbbell at your left shoulder, feet shoulder-width apart, knees slightly bent, glutes squeezed, and core tight.…