Don't Always Train Abs at the Same Speed

Regular readers are well aware that m&f recommends changing up your rep speed from slow and controlled to fast and explosive, allowing you to utilize more fast-twitch muscle fibers to build more power, strength and size. According to new research from Spain, scientists tested the muscle activity of subjects’ rectus abdominis, external and internal obliques, and spinal erectors while they did crunches at rep speeds of four seconds, two seconds, 1.5 seconds, one second or as fast as possible. They reported in a 2008 issue of the Journal of Strength & Conditioning Research that as the rep speed increased, so did the activity of all four muscles. The greatest boost occurred in subjects’ external obliques, which were hardly involved in the crunch at slower speeds but increased by more than six times at the fastest speed. So don’t fail to vary your rep speed. The fast reps will help recruit more muscle fibers in the midsection and turn the crunch, which targets the rectus abdominis, into an effective oblique exercise.