KEY TO Perfect Posture

BRIDGE EXERCISES, where you lie on your back and raise your hips, can strengthen your glutes and hamstrings.

- BY STACEY COLINO

And marching bridges-a next-level move-engage multiple muscle groups and challenge pelvic stability, back stability and core strength and stability.

"A marching bridge is a great exercise because it's asymmetrical," says Keli Roberts, an exercise physiologist with the American College of Sports Medicine. "As you lift one leg, the other leg bears all your weight and rotational forces are placed on the pelvis." What's more, marching bridges can help prevent back pain and improve posture. They also provide a dynamic stretch for your hip flexors and psoas muscles, which run from your lower back to the top of your hips on either side of your spine and can get especially tight if you spend long hours sitting.

To gauge your ability to do marching bridges with proper form, try the challenge at right.

1 Lie on your back on the floor with your arms at your sides. Bend your knees and place your feet flat on the floor, hip-width apart, so your feet are under your knees.