Get a Beach Body Fast
By Marty Munson
Avoid a Toning Plateau
When working on your abs or underbutt, the key to consistent progress is to do less every three weeks, not more. On the third week of your program, decrease the number of repetitions by a third. In the fourth and fifth weeks, increase the weight and take an extra 30 seconds of rest between sets (but keep the number of repetitions the same as week three). During the sixth week, drop the number of repetitions again (like you did in week three), and so on.
From RealAge.com: Build a Better Body With a Personalized Workout Plan