To maximize results abs should be trained with both high reps and low reps. To get the results from you low rep sets weight will need to be added, which brings us to our next myth. MYTH #4: “USING WEIGHT FOR AB EXERCISES WILL MAKE YOUR WAIST BULKY” This actually ties into the high rep theory of ab training. I often hear people say that you should only do bodyweight exercises for very high reps. When I ask them what their reason is for doing this, the usual response I get is, “It keeps the abs tight.”