The pro: Molly Day, group fitness instructor at Equinox locations in New York City
The workout: Master of One is based on the premise that you only need a single weight to have an effective workout. “The class focuses on training the body asymmetrically,” says Day, doing each exercise on one side at a time.
The strategy has the unique benefit of evening out imbalances in the body. When you work both sides together (as a typical kettlebell swing does), the stronger one can pick up the slack. Engage each individually, though (like with a single-arm swing), and you’re forced to address those weaknesses.
This routine, created by Day and inspired by Master of One, has the same setup and payoffs. First, warm up with a few cardio moves to raise your heart rate such as jumping jacks, high knees, and skaters for 30 seconds each. Then, do a few dynamic stretches like front kicks, Downward Dog to lunge, and toe touches.
Each of the two blocks include four loaded exercises labeled A through D and two bodyweight moves for core and cardio. You’ll perform the A through D circuit first on the right, finishing with the core move, then repeat it on the left, ending with cardio.
Choose a weight that you can lift consistently for an entire interval, testing a handful of reps with a few different sizes if needed. Perform the workout 1 to 2 times per week to build strength and endurance.
Stand with feet at hip width, knees slightly bent, holding a dumbbell at your right shoulder in your right hand, as if at the top of a bicep curl. Hinge at the hips, keeping your hips and shoulders squared, and swing the kettlebell along the right side of your body (turning your palms toward you) and as far behind as you can, then swing it forward and return to standing with the weight at your shoulder.
Stand with feet at hip width, knees slightly bent, holding a dumbbell at your right shoulder in your hand, as if at the top of a bicep curl. Simultaneously pivot your body to the right, lower into a lunge, and press the kettlebell overhead and slightly in front of you. Reverse the motion to return to start.
Perform the single-arm swing, then move directly into the shot-put. Continue this sequence.
Lie on the floor with a dumbbell in your right hand. Extend the right arm straight up (with wrist above the shoulder) and lift the left leg, getting it as close to perpendicular to the floor as you can. Reach the weight toward the left foot, lifting your shoulder and upper back off the floor. Reverse the motion to return to start, keeping your core engaged throughout.
Lie on the floor with a dumbbell in your right hand. Extend the right arm straight up (with wrist above the shoulder) and lift the left leg, getting it as close to perpendicular to the floor as you can. Simultaneously lower the leg until it's 2 inches above the ground and bend your right arm at the elbow, lowering the weight to your ear. Reverse the motion to return to start.
Perform the sit-up with opposite toe reach, then move directly into the tricep extension with leg drop. Continue this sequence.
Lie on your stomach with your arms extended overhead (so that your head is between them), palms facing the floor. Lift the arms, chest, and legs off the floor and perform flutter kick with both your arms and your legs. Move opposite limbs in sync, so that the left arm and right leg move together and vice versa.
Stand with feet at hip width. Simultaneously bend at the knees and hinge slightly at the hips, then jump forward as far as you can, using your arms for momentum and landing softly on the balls of your feet. Shuffle back to start and repeat.
Stand with the right knee raised, holding a dumbbell with your right hand in front of your right shoulder, as if at the top of a bicep curl. Rotate your body by stepping the right foot about 18 inches back with the toes pointing back and to the right. At this point, each foot should be turned out. Simultaneously lower into a sumo squat and perform the first part of a bicep curl, lowering the weight between the legs. Reverse the motion to return to start.
Stand tall with a dumbbell in the right hand in front of your shoulder, as if at the top of a bicep curl. Simultaneously hinge at the hips, extending the right leg behind you, and lower the dumbbell until chest is parallel to the ground. Reverse the motion to return to start.
Perform the transverse squat with bicep curl, then move directly into the single-leg deadlift. Continue this sequence.
Begin in a high plank with a dumbbell in the right hand, shoulders stacked over wrists, and feet at hip width. Row the dumbbell up to chest height, then lower it to return to start.
Stand with feet slightly wider than shoulders with a dumbbell on the ground between your feet. Get into a squat with the knees bent at 90 degrees and grab the weight with the right hand. In one swift motion, power through the lower body to stand tall and pull the dumbbell up to your chest, with the right elbow extend out to the side. Drop the elbow to your side and press the weight overhead. Reverse the motion to return to start.
Perform the renegade row, jump your feet forward and outside of your hands, then move directly into the snatch. Continue this sequence.
Sit on the floor leaning back slightly with a straight spine, chest up, legs together, and feet lifted off the ground with a 90-degree bend in the knee. Extend your arms forward with hands clasped together. In small, controlled movements, twist the upper body slowly to the left, then to the right, keeping your legs as still as possible.
Stand in an athletic stand, with feet wider than hips knees slightly bent, core engaged, and arms bent at your sides. Jump to rotate our body 90 degrees to the right, maintaining the same stance, then quickly jump back to center and perform a tuck jump, lifting your knees while you're in the air. Repeat on the left side. Continue, alternating sides.