'Quick Abs and Core Workout' is less than ten minutes long. This no equipment abs workout will have your abdominal muscles burning like crazy. It consists of seven exercises to fire up your core, while toning and trimming all those pesky problem areas. This routine uses all major abdominal muscle groups so you'll probably drip a little sweat here and there as well. Mat is optional and moves require very little space. Trainer: Melina Christidis.