[cesarbs]

Now I'm wondering if I have some degree of that. I've just commented on a sibling comment that while I love exercising, I just feel terrible right after it.

I also have this funny thing where I can't build endurance. I've been doing push ups on every work out and I can't for the life of me do more than 20. But I have no trouble increasing difficulty (putting hands closer, elevating feet, etc.) or weight (for things with weights like squats).

[jMyles]

How old are you? Some people don't develop endurance until their 30s, 40s, or even later! (see Diana Nyad)

I had pretty good endurance in my 20s, but noticed a huge boost in my early 30s.

[cesarbs]

Interesting! I'm 29. Looking forward to my 30s :)

[jMyles]

One interesting data point is to look at the age of UFC champion for your weight, who is probably one of the most fit people in the world.

However, you need to (sadly) keep in mind that weight-cutting is a thing and compensate for that.

So, for example, if you weigh, say, 175-210 pounds, presumably you'd be in either Welterweight or Middleweight.

The champions of these divisions are 34 and 37, respectively.

Of course, they cut a substantial amount of weight, which favors younger fighters. It's possible they'll be at their max fitness in another 5-8 years, even though their capacity to cut weight will have diminished.

There's a message in the zeitgeist that max fitness happens in early 20's, but the evidence, at least in the martial arts world, is that it's late-30's to late-40's.

[tertius]

How often do you do workouts? How far do you push yourself on number 20?