Is clenching one's legs and torso bad form for squeezing out one more push-up when going to failure?

Question

When I'm doing push-ups to failure, most of them are relatively effortless, then I'll have 2-3 where I'm feeling the strain in my arms and they start feeling rubbery, and then I can squeeze out 1-2 more push-ups, but only by clenching the muscles of my torso, my buttocks, and my legs. I've tried experimenting with not doing that (and thereby doing a few less) and it seems like that's correlated with not feeling muscles soreness the next day (it's not 100%, but those 1-2 extra push-ups just seem to put me over the edge).

I know that muscles soreness can be sign of breaking them down to build them back up, and that the last few reps, when you initially think you can't do any more, are where you're really getting the benefit of the exercise because you're pushing your limits. But, such pain can also mean that you're doing something wrong, or pushing yourself into the area of damage. So, the long and the short of it, is tightening those muscles to squeeze out the last rep or two a bad thing?

Answer 1

Clenching your torso and butt is a common tip* in proper push-up technique. It helps keep your entire body straight and flat. Push-ups are a core exercise as much as an arm one, so it does make sense that engaging more of your core would be beneficial.

The sudden ability to do two more may be because you're in a bad position to begin with and this corrects it (butt too high or too low usually). It could also be you're focusing much harder so mentally you're capable of doing more.

It's always a good idea when doing push-ups, or any workout for that matter, to film yourself on a side-angle. With a push-up, you should be flat and straight from head-to-heel. While filming yourself, you may find that you suddenly correct yourself when you clench.

These tips also helps with planks.

*It's step 2.

Answer 2

No, it's not bad to contract the muscles of your torso, buttocks, and legs during push-ups, regardless of whether you're going to failure. You must be contracting them to some extent regardless. Consider: Why would not want to contract those muscles?

Answer 3

Its not bad. You are probably shifting your weight by doing this. I got the standard pushup PhD from the Army. There are several different ways to do a pushup and if you do a set each way you'll get more of a workout in and do more overall. The biggest boost in strength Ive gotten from pushups have come from repeatedly going through muscle failure in many different ways in the same workout. Using my knees became a normal part of my routine. Also became a fan of the 8 count pushup where you start standing and get down to do two then recover. Im not very strong in my arms so Ive always had to work harder than others to get that strength, so that was one good way for me to get it.

For situps though I never grabbed my legs and followed the advice that it will hurt your back, but I did the same thing in general. There are a bunch of ways of doing a situp too.

Actually Ive started doing the same thing for running related strength training.

Yeah so the answer is yes because overall you extend the session training yourself to do that one fundamental movement...

... darn, another reason for long runs.