enter image description here

Image and question have been updated for clarity!

The image above is a side view of a semi-transparent skeletal muscle. The dark red lines represent individual fibers, the blue lines represent tendons. The pink area also consists of muscle fibers, but it is made transparent for the purpose of the demonstration. Please assume the fibers are properly encased in fascicles and fascia. Tendons connect the muscle to the bones. The bones can move towards the center of the image if pulled. The arrows show the flow of force during contraction along each fiber.

The muscle has grown large enough that the outer fibers protrude around the tendon (where they connect). During contraction, do the protruding outer fibers help pull the tendon towards the center of the muscle like the internal fibers in the middle of the muscle do? If so, how is the force controlled and directed to accomplish this?

It seems there exists athletes with this type of anatomy (such as very large bodybuilders) but the bio-mechanics of this type of anatomy completely confuse me. It would seem the flow of force of the outer fibers would pull the tendon away, unless the force is somehow redirected. Thank you so much for your insight on this!!!

  • $\begingroup$ Could you try to clarify this? Is your drawing of a muscle fiber showing a cross section or a side view? My guess based on your quesiton is that it's a side view (meaning contraction is in the same plane as the tendon) -- is that right? If that's the case, knowing that muscles only contract (meaning they are unidirectional in their "tugging" ability), I would suspect your tendon would move in the same direction as the muscle fiber. However, without knowing where your muscle is attaching (i.e., which side is the origin vs insertion) it's difficult to say which direction this muscle is moving. $\endgroup$ Mar 17, 2017 at 17:19
  • $\begingroup$ I recommend thinking about this a little more and then trying to clarify both your picture and what you're asking. Perhaps also provide a reference for your athlete example to help clarify. Thanks. $\endgroup$ Mar 17, 2017 at 17:21
  • 1
    $\begingroup$ Sorry about the confusion, I went back and edited the question and image to try and clarify things! I hope the question makes more sense now! $\endgroup$
    – Jon Yang
    Mar 18, 2017 at 23:16


You must log in to answer this question.