Another great exercise is the weighted crunch on an exercise ball or stability ball. Not only will the weight help increase the resistance, but it will also make your abs work harder. The use of the stability ball will cause the abs to work harder, because they need to remain centered and a lot of work on the abs as a whole is happening.
Simply lay on the exercise ball and make sure to be comfortable. Get a weight, it cab be anything, it does not have to be a dumbbell or medicine ball, it can be a rock if you have one. Then place it overhead and perform crunches for a good, 12-20 reps and then rest, then repeat for 3-4 sets.
