Getting a bigger waist is best done by building the thickness of your core muscles instead of packing on the abdominal fat. Exercises to beef up the size of your lower back muscles, your obliques and your rectus abdominis muscles must be done with progressively heavier weights just as you would lift to build your biceps. Squats, deadlifts and hyperextensions with weights will enlarge the muscles of your lower back. Forego crunching an infinite number of repetitions and instead use heavy enough weights in which you can only complete six to 12 repetitions per set for all exercises.
Decline Weighted Crunches
Grab a dumbbell then situate your body on a decline bench in an upright position. Hold the bar of the dumbbell with both hands, lowering your body with the dumbbell extended directly over your chest.
Lower the dumbbell just beyond your head, nearly in line with your trunk; keep your arms straight. Perform a crunch as you simultaneously draw the dumbbell back over the center of your chest and raise your trunk off of the bench.
Slowly return to the start position with the dumbbell just beyond your head. Complete four to six sets using a heavier dumbbell for subsequent sets.
Barbell Side Bends
Remove the safety bars of a squat rack, then position a barbell across your trapezius muscle, near the base of your neck, and your shoulders as if you are going to do a squat.
Place your feet wider than your shoulders and bend your knees into one-third of a squat. Extend both arms over the length of the barbell to hold the barbell in place.
Contract your transverse abdominis muscle tightly, sucking your navel toward your spine. Bend your waist, lowering the right side of the barbell as far as you can. Contract the left oblique muscles to return to an upright position.
Lower the left side of the barbell as far as you can then return to an upright position. Complete four to six sets of 12 repetitions per side.
Reverse Crunches on an Incline Bench
Position an incline bench to nearly 135 degrees. Lie on the bench as if to do incline presses but place your pelvis on the inclined portion of the bench, holding yourself in place by grasping the upper end of the bench.
Contract your rectus abdominis muscles to raise your pelvis slightly off of the bench. Complete one set of 10 repetitions.
Secure 5-lb. ankle weights to each ankle then complete four to six sets of no more than 12 repetitions per set.