The age-old question in bodybuilding is whether it is better to do crunch exercises in a slow and controlled manner, or at faster speeds. Until recently the advocates of the former approach were more numerous. When it came to strength exercising, the maxim ‘slower is better’ held true. And to no surprise – the idea behind slow workouts is fairly logical.
When going slow you transfer all the tension on the muscles, forcing them to work hard, instead of relying on momentum and making the exercises easier. The ‘recommended’ speed for performing crunches is 2 seconds on the positive reps and 2 seconds on the negative reps. However, new studies have emerged proving that this widely accepted truth no longer holds as tightly as one would believe. Some of them even argue that crunch exercises performed at faster speeds (1 second instead of 2), are more efficient then crunch exercises performed at lower speeds. The increased speed helps in recruiting more muscle fibers, which in turn results in improved muscle development. According to this study, the strength gain of slow exercising is 15% while that of fast exercising is 39%.
Another study performed by Spanish researches revealed that increasing the speed can substantially boost the muscles activity. They base their results on testing the muscle activity of rectus abdominis, external obliques, internal obliques and spinal erectors while the subjects performed crunches at 4 different speeds – 4 seconds, 2 seconds, 1.5 seconds and 1 second. Turns out, the muscle activity of all four muscles increased at increased speed. Moreover, the activity of the external obliques saw a raise of over six times when the crunch exercise was performed at fastest speed. Comparatively, they were hardly involved at slower speeds.
Again, from a logical point of view, this should not come as a surprise. Just compare the leg muscles of long track and fast track runners. While the legs of marathon men are lean, their faster brothers sprinters, who engage in explosive movements, tend to have more muscular legs.
Nevertheless, this doesn’t mean that from now on you should go through your crunch exercises as a fast train. It’s just a proof that increased speed can improve your results. Try mixing the speed of your crunches, always beginning at slower pace, and gradually increasing to faster.