By Eric Velazquez, NSCA-CPT ProSource
Researchers find that speed is key to getting maximum benefit from crunches
Bodypart: Abs, Obliques
One move that everyone does when training abs: the crunch.
One move that everyone is sick of: the crunch.
What a tragic duality for this fundamental exercise. While the crunch is ultimately effective at building stronger, better-looking abs, it can be nauseatingly boring for the more experienced trainer. Crunch, hold, down. Crunch, hold, down. Arrrgh!
But because it is so effective at touching up your rectus abdominis (read: six-pack), it would be nonsensical to abandon it. A better approach, as with many exercises, is simply to find a version of it that is more challenging. Even the crunch, one-dimensional as it is, has a number of varieties that can be employed. You can change the incline, add a twist or change the pace. Here, we'll focus on the latter.
Spanish researchers tested the muscle activity of subjects' rectus abdominis, external obliques, internal obliques and spinal erectors while they performed crunches at rep speeds of 4 seconds, 2 seconds, 1.5 seconds, 1 second or as fast as possible.
Guess what they found? The faster the rep, the greater the muscle activity in all four areas. Strangely, the greatest boost in muscle activity occurred in the external obliques, which were hardly involved in the crunch at the slower speeds, but rose by over six times at the fastest speed.
In other words, fast beats slow when it comes to the crunch and, as a bonus, your obliques are worked to a greater degree than in the standard speed crunch.
Make sure to still work through as complete a range of motion as possible.
Since the burn is likely to set in later, you may want to use higher reps (20+) when crunching fast.
To get the best of both worlds, alternate between fast and super-slow crunches from set to set, or add an extended hold (10 seconds or more) on your final rep of each set.
Miguel Hernandez University (Elche, Spain)