"3 Game-Changing Ab Exercises for a Stronger Core in Just 15 Minutes"

After adding hundreds, plank shoulder taps, and roll-ups to her ab routine for a week, the author noticed increased muscle definition, improved flexibility in her hamstrings, and easier performance of the exercises. She also found it simple to progress the exercises and felt the burn, recommending these moves for a challenging core workout, but advises against working abs every day to allow for rest and recovery.