The lower abdominal muscles – the transverse abdominals – wrap like a belt in front of the hip bones and around the small of the back. Think of these muscles as your own internal corset that holds in your internal organs and helps you sit, stand and walk each day. Your favorite part may be the way this muscle flattens your stomach and strengthens your lower back! Try the leg drops a few times a week and you’ll quickly see results.

Leg Lifts

Starting position: Lie face down on the floor with your arms in line with your shoulders, palms up, and raise your legs until they are perpendicular to the floor, knees slightly bent (a). Pause for three to five seconds to lower your feet as close to the ground as possible (b). Reverse the movement to return to the starting point. Replication.

Repetitions → 15 times + 3 sets

Bike Crunch

Starting Position: Lie flat on the floor with your lower back pressed into your mat. Interlace your fingers to create a cradle and place it behind your head. Elbows should be out of your peripheral vision. Float your legs to a position on the table, ankles aligned with knees. Engage the abdominals. Lift your head up, so that your shoulder blades are in a hovering position relative to the floor. Straighten your right leg lengthwise while turning your upper body to the left. Bring your right elbow toward your left knee. Twist at the ribs and lead with your shoulder rather than your elbow. Switch and repeat on the other side. Continue for a full count.

Form Tip: Don’t pull on your neck. Instead, use your abs to lift, says Phelps.

Rest for best results: Aim for 3 to 4 sets of 15 to 20 reps.

Alternating Lifts

How to do it: Lie flat on your back with your arms slightly bent under your hips, palms facing down. Lift both legs off the floor so they are 6-8 inches off the ground. Slowly raise your right leg until it is at a 45-degree angle while keeping your left leg a few inches off the ground. Switch legs: Slowly raise your left leg until it is at a 45-degree angle and lower your right leg until it is a few inches off the ground. Continue alternating legs.

Rest for best results: 50 reps max.

Scissor Crunch

Lie on your back, bend your knees and pull them into your ribs. Then lift your legs toward the ceiling, contracting your abdominal muscles and press your lower back into the floor. Lower your right leg and scissor your legs so that your right leg comes up. Do these movements slowly and steadily. Repetitions → 15 times + 4 sets