Again, "Sure!" We simply don't know, and there's no good reason why it can't ever be so.

However, will cheetah muscles be better? We don't know.

This possibility is strongly in the speculation part at the end of essay. It's science fiction at this time.

We might instead have nanomachines which augment the muscles and tendons. Is that more likely to occur first? (To avoid detection, smuggle it into the body through a glass of water, and have it geolocated so it breaks down quickly into normal body waste products.)

Given the reasoning for why we are at our limit given a few comments up, that specific combination is unlikely to yield benefits, as the ligaments cannot take any additional strain. Are there better ligaments to be swapped in a well?