In a way that is true. However, nervous control has a huge influence, that and the incredibly low bodyweight! Funnily enough, I also did a unit on further generation and control of movement that was almost completely on the nervous system! Cats are used a lot, mostly for gait actions recordings and are very well researched. The tendon length has an influence because it acts like a lever. However, you can't change the length of the lever yourself which means you can't train it. Achilles tendon length is actually the reason why many elite level sprinters are black - they are genetically determined to have longer achilles. The tendons transmit the force of muscle contraction to move the bones - that is all. Their strength is purely structural ie. maximal strength as they have no contractile components. Although their hysterisis will have an influence, it is negligible compared to other components of movement. No, the muscles do begin to fail but they continue to contract. If they failed, you would fall over. Simple.The large MMAist probably falls over first in standing practice because he has the lowest amount of local muscular endurance combined with higher bodyweight, which means it is a lot harder for him to hold positions for a long time. Muscle strength is a complex thing, but on very light effort like holding positions you are talking purely endurance rather than strength. Hysterisis is something that is generally trained as an aside in most sports training - to concentrate on it would be foolish unless you are an elite athlete. SSC efficiency is trained through repeated quick movements similar to what you are practicing, like a footballer working on change of direction. However, greater maximal strength, explosive strength etc. will give better results. If you have control of their body, they will find it difficult to strike your legs, especially without leaving themselves open to a sweep or giving up into an even worse position. It is very hard to catch a leg in the clinch that is trying to knee you because if you go for the knee, you are leaving yourself in a poor situation position wise and you are exposed to many other threats. I'm sure others like Ikken can expand on this. How can someone step into your centre out of knee range? Anyone in a clinch is in knee range - pulling away leaves you in the best position for a knee if the person has control of your head. The best way to counter knees in the clinch is to pull the opponents hips in. If you have a good clinch game, nobody is stable enough to not be moved - that is the idea! Also, if someone is stronger then you are at a disadvantage all-round anyway, so they can apply to all other situations. It is upto you what you do with someone stronger. There are a million "what-ifs" in this situation! Again, feel free to ask any more questions on the anatomy front.