The Infonian

To engage 650 muscles with only 1 dumbell, try this simple workout:

Beginning with a 15-pound dumbbell. Use slightly heavier dumbells as you advance, but don’t use dumbells heavy enough that require you to rest between exercises.

Complete the circuit by doing each exercise for 45 seconds. Rest 1 minute. Repeat 2 or 3 times.

1. Woodchopper
Keeping your arms straight and feet just beyond shoulder-width, start with a dumbbell above your right shoulder. Bend your knees and powerfully twist your torso left as you pull your arms down and across your body. When your hands reach beyond your left ankle, reverse the movement to bring the dumbell to the starting position. Then switch sides. Always contracting your abs to avoid injury.

2. Arms-out squat
Standing with your feet slightly wider than shoulder-width apart, grab a dumbbell by the ends and hold it directly out from your eyes. Now press the ends together as you simultaneously thrust your hips back, bend your knees, and lower your body until your thighs are parallel to the floor. Pause, then drive your legs back up.

3. Standing pressout
Keeping your feet at shoulder-width, grip a dumbbell by its ends and hold it by your chest. Try to press the ends together as you simultaneously trust the dumbbell away from your body and slightly up to eye level until your arms are straight out. Pause, and pull the dumbbell back as you pull your shoulder blades together.

4. Towel row
Secure a towel around a dumbbell’s handle. Grasp an end of the towel with each hand and stand with your feet shoulder-width apart, knees slightly bent. Bend at your hips, keep your lower back straight, and lower your torso until it’s almost parallel to the floor. Pull the towel ends to either side of your abdomen. Pause and lower the towel.

By not incorporating reps in this speed routine, you’ll concentrate on form and activate more muscle fibers, says creator C.J. Murphy, co-owner of Total Performance Sports in Everett, Massachusetts. Complete the circuit by doing each exercise for 45 seconds. Rest 1 minute. Repeat 2 or 3 times.