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Muscle Physiology Question

What happens to the myosin heads during an eccentric contraction?

Do muscle fibers shorten at all to continue producing force to control a load during eccentric contraction?

I’m curious about the specific physiology of eccentric contraction, because I have MANY books on the topic but none of them cover this in much detail.

Bump. I even attached the greatest .gif in existence :expressionless:

I can’t answer your question, but I can tell you that you’d probably get more responses if you posted this in a diffrent section.

Mysoin and actin start to elongate/separate back to normal positions

Muscle fibers shorten during the concentric.

K, thanks.

I’m a lurker, but I thought I’d give some of my input. During eccentric phases the muscle is contracted, and slowly increasing its length back to normal or resting.

At this point, there is an applied tension that is slowly decreased, allowing for the ‘lowering’ phase, where the muscles are becoming less contracted. Hope that helped :slight_smile:

… back to lurking

Thanks for the input.

I understand that much, so I guess myosin must just slide back into its original position. This is what I thought previously, but wikipedia says that we don’t know what happens to the myosin heads during eccentric contraction.

I’ve been told that muscle fibers all lengthen during eccentric contraction, but I’ve heard contradicting evidence from other sources.

well, it is called the sliding filament theory

[quote]Flow wrote:
Thanks for the input.

I understand that much, so I guess myosin must just slide back into its original position. This is what I thought previously, but wikipedia says that we don’t know what happens to the myosin heads during eccentric contraction.

I’ve been told that muscle fibers all lengthen during eccentric contraction, but I’ve heard contradicting evidence from other sources.[/quote]

A couple things to consider are that these aren’t the only structures in a muscle and that these structures all behave differently at different lengthening velocities and magnitudes.

If you’re interested in this sort of thing, check out the works of Walter Herzog on PubMed. His lab has done some pretty cool work on the subject (as have others).

-Dan

Thanks buffalokilla.

Yeah, you’re right Jehovasfitness. It is a theory after all