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Of course the number of muscle cells can be different person to person. But within a single sarcomere, are we all the same?

Would the frequency of the protein motor binding and release cycle different for each person? And if that is a constant, then do we all attain the same speed of muscle contraction?

If not, what causes the different speed?

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    $\begingroup$ In consideration of the fact that protein structure is encoded by your DNA, I would assume that it could be possible to have different muscle-contraction speeds that are dictated by the exact amino acid composition of a sarcomere. I don't know if the effects would be measurable or not. But I suppose it could be possible to have sarcomeres that are able to make stronger bonds than the sarcomeres of other people, thus having an increased reaction rate. And, as you said, release cycles might not be the same for each person which could also contribute. $\endgroup$ – Bob Apr 8 '17 at 17:06
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    $\begingroup$ @user1589188 if you talk about potential then initially yes, but considering the fact that muscle contraction is regulated chemically by the nervous system they would be different in different people even of the same age. Unless the portion of the muscle fibre under consideration is damaged then they would show same frequency for requiring Ca+2 and ATP level. (Mutation in the DNA most likely lead to failure of proper binding) $\endgroup$ – user30561 Apr 9 '17 at 3:21
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    $\begingroup$ Muscle contraction speed is also situation dependent-- varies with force and length even within an individual, even just by virtue of the sliding filament model... I'm not sure that the initial assumption that an individual sarcomere has a fixed speed is correct. $\endgroup$ – Kara Apr 12 '17 at 0:08

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