First, I'm free to admit that I don't know exactly where along a limb the muscle mass really is and also that I have a very simplistic view of "short muscle" - so if I'm conceptually wrong, please correct me or point me to some links.

When I was doing Muaythai, I think I had strong legs, specifically the muscle responsible for stretching the leg (quadriceps?). This muscle also seemd to be bulked on the upper end of my thigh, away from the knee. The range of movement of what I did with the leg was typically very close to a stretched position. Since I started going to a gym (and doing presses with the leg with a higher range of movement), I notice that my body builds muscle nearer to my knees ( or there's a new fat-deposit) - a good thing in my book, because I hope for more stable knees.

Is my observation plausible? Can this be generalized for the training effect of movements with different ROMs?

2 Answers 2


I suspect that you previously noticed more muscle near your upper thighs because your quadriceps were not very developed except for the rectus femoris (one of the 4 quadriceps muscles), which also acts as a hip flexor that would be used to develop a lot of the power during Muay Thai kicks and knees. (This is a quirk specific to the Muay Thai style of roundhouse kicks.) It would be developed disproportionately to the other quadriceps unless you were doing strength training.

The muscles you're seeing develop now are the vastus lateralis and medialis. These are two other quadriceps muscles with a bulk of their visible mass closer to the knee.

However, this doesn't generalize well. The idea of muscle building close to the proximal joint vs distal joint is very specific to the motions you happened to be doing and the structure of the quadriceps (because they're actually 4 different muscles).

What does generalize is that you will get strong in the range of motion that you exercise. You were previously exercising Muay Thai kicks, which demanded strong hip flexion, so your upper quadriceps got strong. Now, you're exercising strength being pushed through your legs to the ground (or leg press platform), so the rest of your quadriceps are getting strong.


When you say 'range of motion', both a muaythai kick and a leg press have the same ROM...which is zero. Range of motion is determined by the final joint angle minus the initial joint angle, and since both movements are a cycle, you get zero. So maybe that's not the best vocabulary to use.

As far as 'the muscle responsible for stretching the leg', muscle is responsible for stretching the leg if the contraction is what is called an 'eccentric contraction' -- meaning the fibers lengthen during the contraction. You get this often when you are resisting gravity, like trying to maintain a moderate speed when running downhill. I'm not sure if this is what you are talking about?

Muay thai kicks follow the classic 'stretch-shortening cycle', where force is developed using eccentric contractions followed quickly by a concentric contraction. This is the same strategy you will spot in many high-power generation movements. As such, the hip flexors (illiopsoas) will contract but isn't a prime mover, as opposed to karate-type snap kicks that have a tremendous demand on the flexors. If anything, the posterior chain will contribute more during the preparation phase than the flexors on the anterior of the body, since that's when the GRF has time to develop, being that you are in double support.

I suspect the reason you are seeing more hypertrophy around the patella is because, if you knew it or not, you are now training for hypertrophy in a closed-chain movement. Your volume, intensity, speed, and recover time is now totally different than it was in muay thai.

  • you are seated and aren't challenged for balance, like in kicking -- thus you can apply more force as you do a knee press.
  • leg press is symmetric, meaning you can overload the muscles in the leg in a safer manner, which gravitates you towards moderate to high loads.
  • leg press puts higher eccentric demand on the quad than you could ever get in muay thai, and it's the eccentric demand that leads to the hypertrophy you are noticing.

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