Stomach crunches: more quickly, or fewer but holding them?
November 30, 2013 4:53 PM   Subscribe

Is it better (in terms of muscle building) to do a large number of stomach crunches quickly without pausing at the 'up' part of each crunch, or fewer but pausing and holding the muscles tensed for a few seconds with each crunch?
posted by paleyellowwithorange to Health & Fitness (7 answers total) 3 users marked this as a favorite
Best answer: I've found that if I do crunches quickly, I tend to use a propulsive motion that mostly seems to be powered by the muscles of my back. If I do crunches slowly and come to a complete stop at the top of the rep, I can isolate the range of motion when I'm mostly using my midsection and do, in fact, feel the exertion there.
posted by Nomyte at 5:01 PM on November 30, 2013 [1 favorite]

Exactly as Nomyte states. Fast = momentum = cheating yourself. Slow and controlled with a pause at the top = isolating the abdominals.

Now please add in some planks.
posted by matty at 5:08 PM on November 30, 2013 [4 favorites]

Slowly, and hold.
posted by seawallrunner at 5:58 PM on November 30, 2013

What they said. The buffest SOB I ever met in the Army did half the reps at half the speed.
posted by Etrigan at 5:58 PM on November 30, 2013

I was under the impression that any exercise you can do more than 10 of in a row is going to be more of a cardio workout than a muscle-building one. So, I guess, whichever is harder? And if you can do more than ten of both styles, then, neither?
posted by Jacen Solo at 6:18 PM on November 30, 2013 [1 favorite]

Slower = harder workout. And do some different styles of crunches - legs straight up, bent at 90 degrees, holding a medicine ball, on an incline, alternating sides, for maximum development of all the different parts of your abs.
posted by leslies at 7:26 PM on November 30, 2013 [2 favorites]

"Better" in what sense? What is your goal?

Doing any exercise "too fast" is necessarily going to be bad. If it weren't, it would just be doing the exercise "fast." But where is the threshold? Probably not something distinct, but I would try to focus on proper form rather than speed to keep yourself from "cheating." (Cheating, in a training sense, is not something like inflated numbers so you sound stronger compared to your bros or going to the gym with a different workout buddy on the side. Rather, it just means recruiting additional muscles that aren't the focus of the exercise. In some instances it may be called for, a sort of a "self spot" to eke out a few more reps, but for the most part it should be avoided as much as possible.) 1 (see "Cheating")

Now, let's say your form is perfect. Is there any benefit to slowing down further? Some would argue yes, that spending more time on each rep ("time under tension") will force the muscle to work harder. While I haven't heard any argument that it contributes to strength or explosiveness, it seems to be more for muscle growth and endurance. 2

Slowing down even further, and your exercise changes from isotonic to isometric. While isometric exercises are not completely without merit, the consensus seems to be that they are not as beneficial as isotonic exercises. 3

I will be the first to tell you that the sources I linked are not the most scientific, but they do seem representative of current ideas about training in the gym (by both professionals and brofessionals alike). I personally would recommend 1) just doing them (showing up is 90%!), 2) make sure your form is good and your speed is comfortable yet challenging, and 3) move to a decline bench and add weight to build strength/explosiveness instead of slowing down the exercise to build mass/endurance (unless that is a priority of yours).
posted by GooseOnTheLoose at 7:51 PM on November 30, 2013

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