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Stretching has many advantages, among other things it helps us to be flexible in our movement (which is an advantage?!).

But why do we need to actively stretch, it seems that the body wants to shorten the muscles by evolution (e.g. when training often in fitness studio). This is the opposite of what we do when stretching.

It seems to be that there are advantages of being not stretched. So what are these advantages / what is the evolutional rationale?

Edit: Why this question is different from this question:

That question asks, why we automatically stretch sometimes after e.g. sleep. The answer is that we stretch the soft tissues because of transitions of high and low activities (especially after sleep, in which we ease the tension in our muscles [muscular antonia]).

This question asks something different. It asks about explicit stretching in sports and not about automatically stretching behavior. The aim is different. In sports we stretch because, we want to lengthen our muscular. The question is why lengthening doesn't seem to be a good thing from an evolutional perspective.

Edit 2: I'm not sure, if it is clear for everybody, what I mean, so I add a succinct example: Why would it be bad (evolutional rationale), if everybody could do a split (gymnastics) by nature (disadvantages?)? In our reality, the ability to do this is almost always an result of stretching. This is only one extreme example, mostly people don't strech to such extremes. Maybe this now helps to understand, for what this question heads.

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  • $\begingroup$ Now I understand your question, thanks for editing it. I just retracted my close vote. $\endgroup$ – user24284 May 15 '17 at 7:20
  • $\begingroup$ @GerardoFurtado Thanks, shall I edit the title to "Lengthening the muscles not good from evolutional perspective? Why do we do it with explicit stretching?"? $\endgroup$ – SearchSpace May 15 '17 at 7:22
  • $\begingroup$ Yes, I think it's a little better. But certainly a top user will edit it again to make the title even more clear. $\endgroup$ – user24284 May 15 '17 at 7:24
  • $\begingroup$ I don't know enough about this to make an answer but I wonder if you might find some answers in looking up "hypermobility" or "hyperflexibility", and why it can be bad. There may be a tradeoff between mobility and strength; sometimes you want to bend, but sometimes you want to have a limb "locked in place", and if the muscles/ligaments can stretch too far then you need to spend energy keeping them contracted where you might otherwise not need to. $\endgroup$ – Oosaka Jun 4 '17 at 18:34
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Muscles only ever work by shortening, as you say, but muscles in the human body tend to be found in antagonistic pairs. These pairs of muscles act in opposite directions, one example being the biceps and triceps muscles - the biceps bends the arm (a flexor muscle) while the triceps straightens the arm (an extensor muscle), another example is the quadriceps-hamstring muscle pair in the upper leg.

If our muscles remained shortened, our mobility would be impaired. If the biceps muscle remained too short, it would be impossible to extend our arms, for example. Muscles do work by shortening, yes, but it's important for them to be able to stretch as well, and remain long enough for antagonistic muscles to have their full movement be possible as well.

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  • $\begingroup$ Welcome to Biology.SE. Your answer seems good enough to me but please add references (peer-reviewed articles are best, Wikipedia articles or blogs are also okay for common knowledge) to back up your claims and give people starting points for further reading. Thanks! $\endgroup$ – AlexDeLarge Jun 2 '17 at 14:28
  • $\begingroup$ This doesn't answer my question, or at least what I meant. I edited the question. This question heads for streching in the meaning of lengthening the muscle at its maximum resting length (and maybe to shorten the completely contracted length of the antagonistic muscle partner). $\endgroup$ – SearchSpace Jun 4 '17 at 8:44
  • $\begingroup$ Thanks for your comments, both. Apologies that I don't have any references, it was purely reasoning that lead me to my answer so please take it with a pinch of salt, obviously! $\endgroup$ – Jonathan Page Jun 4 '17 at 12:56
  • $\begingroup$ Sorry I haven't been able to answer your question entirely. Perhaps it's just the case that stretching to such extremes aren't that frequently used in a natural setting. It may not be detrimental, but it may not be advantageous enough for it to have been selected for over the course of evolution. This article has some suggestions too: ideafit.com/fitness-library/… $\endgroup$ – Jonathan Page Jun 4 '17 at 13:03

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