Crunches exercise is an abdominal exercise done before any other exercise. It helps to strengthen the core. But one has to have a healthy balanced diet and a regular cardiovascular exercise as well.
Crunches are done very slowly and with control, most of all, you can do it anywhere or anytime.

Reverse Trunk Curl

This only takes some practice!

Lie face-up on the floor with your legs straight up, perpendicular to the ground. Keep your palms face down and at your sides, and bend your knees slightly. Your entire back should remain flat on the floor, as should your shoulder blades. Contract your abdominal muscles, then curl your pelvis up, making your feet go up toward the ceiling. Begin to exhale upon contraction of your abdominal muscles.
You should raise your hips only three to five inches off the floor. Be sure your legs and buttocks remain to relax. the primary work should be done by your abdominal muscles. Pause for a split second before returning to the starting point. Exhale on your way up and inhale upon returning to the starting position. Continue until the entire of fifteen is complete.

If you've never done this before, they may be difficult for you, and you may have to gradually build up to completing the entire set of fifteen.

STARTING POSITION ^^^

ACTIVE PHASE

Back And Shoulder Exercises

Along with the muscles of your abdomen, the muscles of your back have the important task of stabilizing your torso. Your back will especially benefit from the two exercises shown below. The arm and leg raise strengthen the lower back, and the Shrug Roll strengthens the upper back. While all of the functional exercises you will perform improve your posture, the shrug roll, in particular, is an excellent exercise for this because it strengthens your shoulders as well as your upper back. It should be performed without holding weights, You should hold a five or ten-pound dumbbell while performing the exercise.

Arm And Leg Raise

You may have to build to fifteen repetitions in these exercises!
Lying face down on the floor with your head supported by a folded towel and your arms extended over your head. Contract your abdominal muscles and the muscle of your lower back. Raise your right arm and left leg simultaneously. Keep your shoulders and your pelvis pressed against the floor. Do not lift your arm or leg too far, you should feel a gentle tension in your lower back muscles. Return your arm and leg to the floor. exhale on your way up and inhale upon returning to the starting position. take a deep breath and begin on the other side, lifting your left arm and right leg.

Starting Position

Active Position

Stand erect with your feet shoulder-width apart. Keep your arms down at your sides. Begin the exercise by bringing your shoulders up toward your ears as though as your shoulders will go. Pause for a second at the top of this range of motion, then roll your shoulders back while squeezing your shoulde4r blade together.
Again, pause for a second, then drop your shoulders back to the starting position. You should simple breathe naturally throughout the entire exercise. Continue until the entire set of fifteen is complete.

The amount of weight that you select for the shrug roll should not cause undue strain but should cause slight burning sensation by about the tenth repetition. Since there is a very little movement of the weight in this exercise, you can probably use more weight than you think you can. Begin with a five or ten pound of dumbbell in each han. If you can complete repetitions easily, you should add more weight.