#1 Hanging leg raises
The hanging leg raise is a core strengthening exercise that targets the entire abdominal region with an emphasis on the lower abdominals and hip flexors. With your legs completely straight the entire time, tighten your core and use your abs to raise your feet toward your shoulders.
The plank is an isometric core strength exercise that involves maintaining a position similar to a push-up for the maximum possible time. Assume the top push-up position. Now bend your elbows and place your forearms flat on the floor beneath you. Tighten your ab muscles to keep your back flat. Make sure your toes are pointed into the ground. Hold the position for the prescribed duration.
#3 Reverse Crunches
Lie down on your back with your legs fully extended, your arms along your sides, and your palms on the floor. Move your legs up so that your thighs are perpendicular to the floor and your feet are together. This is the starting position. As you breathe in, pull your knees toward your chest as you roll your pelvis backward and raise your hips and upper back off the floor. Hold this position for 1-2 seconds, then exhale as you move your legs back to the starting position.
#4 Oblique Crunches
Lie on your back on the floor. Keep your legs bent in the air at a 90-degree angle. Place your hands on the back of your head with your elbows flared out to each side. This is the starting position. Twist (rotate) your torso to move your right shoulder toward your left thigh until your upper back is off the floor and your right elbow is close to or touching your left knee. Lower yourself back down to the starting position. Repeat the movement, this time rotating your left shoulder toward your right knee. Alternate reps between your right and left sides.
#5 jackknife sit-ups
Lie on your back with your legs straight out on the floor, your arms extended above your head, and your hands touching the floor. This is the starting position. Bring your body to a "V" shape by lifting your legs and torso toward each other, keeping both your legs straight and your arms extended. Lift your shoulder blades off the ground as you raise your legs as close to perpendicular to the floor as you can. Touch your hands to your legs, then lower your torso, arms, and legs back to the floor.