The fastest way to a flatter stomach isn’t doing hundreds of crunches. Rather, the key is to train a deep abdominal muscle that wraps around your midsection called the transversus abdominis (TA). Think of it as a sort of internal Spanx shapewear, smoothing your belly from the inside out. Your TA acts as a natural girdle, and it needs proper training to make your lower abs in particular look and feel flatter and sleeker.

“However you train your ab muscles is how they develop,” explains Linda LaRue, creator of the Crunchless Abs DVD series and a celebrity trainer in Los Angeles. LaRue says that doing standard crunches incorrectly can cause you to build your ab muscles outward. The trick to a flatter belly is “pulling your abs up and in as you work them from all angles.”