In bodybuilding the benefits of long muscle bellies are fairly self evident, just look at Ronnie Coleman's out of place biceps and compare them to Sergio Oliva.

For any sport requiring strength there would also be significant benefits simply due to the increased muscle mass. In the case of the legs, there seems to be a fair amount of literature showing that long achilles tendons and short calf muscle bellies are an ideal combination for runners, so there's an obvious reason why someone would have long tendons and short muscles in the lower extremeties.

I can even make a hypothesis that not having a too long bicep and having a longer tendon distally would allow for better elbow ROM. However, for the forearm, I haven't been able to find any literature, nor think of any practical benefit to having a short muscle belly and long tendons, yet some people have exactly that - a large flare right below the elbow with not much of a taper to the wrist.

Any thoughts on this topic?

  • Could you explain the relation you think there is between the length of a muscle-tendon-complex and the ROM? Then I have an idea about what the answer should try to explain.
    – Ivo Flipse
    Commented Jun 25, 2012 at 8:31
  • If your distal tendon of the bicep is so short that you can't see where the muscle ends and the tendon begins, and you flex your elbow joint, the contracted bicep will get in the way of making a very small angle. If the tendon's longer, even though flexing the elbow joint contracts the bicep, the angle's a lot smaller before the forearm comes in contact with the bicep, thereby preventing further flexion.
    – Robin Ashe
    Commented Jun 25, 2012 at 8:36
  • How much a muscle shortens doesn't depend solely on the length of the muscle belly, but also on the location on its insertion (given it a moment around the joint), the orientation of the fibers in the muscle and the way the tendons are connected to the muscle. I'll have a look in my anatomy books to find some good images for you
    – Ivo Flipse
    Commented Jun 25, 2012 at 8:50
  • sorry its taking so long, but I'm currently moving and those books are in the new house already, so don't have access to it just yet.
    – Ivo Flipse
    Commented Jul 6, 2012 at 7:52
  • So, is this something that can be effected significantly through exercise or fitness? Commented Jul 9, 2012 at 21:04

2 Answers 2


I believe shorter muscle bellies fatigue faster and have greater explosive potential.

To get a full contraction on a short muscle belly, actin and myosin filaments have to attach, detatch, and reattach fewer times hence my belief that it would have greater explosive potential.

  • Interesting thought, but I think that would be offset by longer muscle fibers having correspondingly more binding sites. In a longer fiber, you simply have more sarcomeres per length. I would think that would argue for more sarcomeres being able to generate more power. In any case, it's simply a belief. Would make for an interesting study though.
    – JohnP
    Commented Sep 11, 2012 at 20:58
  • What suggests that short muscle bellies have longer muscle fibers? Also think about this. Shorter sarcomeres have less distance to contract and get the job done faster. Whereas long sarcomeres are the exact opposite. Who would get done digging a large hole quicker: 100 men or 10 men?
    – BryceH
    Commented Dec 11, 2012 at 11:28
  • Depends on the size of the hole and how many of them are working. But if you were to ask who can get 100 holes dug faster, I think the answer is clear. Commented Jul 9, 2013 at 11:23
  1. Muscle to Tendon ratio: Those who have long bellies and short tendons have a greater potential for achieving muscular size than those who have short bellies and long tendons.

  2. Strength: Individuals with long muscle bellies have the potential to be quite strong, because of a larger cross-sectional area.

  3. Lever and Proportions: Those who have favorable lever lengths and body proportions have a greater strength potential in certain exercises because they don't have to move the weight as far as those who have less favorable lever lengths and body proportions. The end result is that they can lift extraordinarily heavy weights

  4. Tendon insertion: The farther away that a tendon inserts from an axis of rotation, the greater the biomechanical advantage and strength potential.

Reference: https://www.t-nation.com/training/4-genetic-factors-that-determine-your-success

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