The common denominator in throwers who can sustain their velocity is elite sequencing & efficiency.

How you create your velocity is more important than just being able to hit a number.

Do your patterns supply the velo or do you rely on active muscular effort from your arm?

One sign of this is a thrower's ability to throw hard at very low efforts (RPE).

When a guy can flip balls at mid 80s+ with very low perceived effort, that's a sign his patterns and sequencing are efficient.

Best example I've seen: https://twitter.com/PitchingNinja/status/1219991130735022080?s=20

When a guy needs adrenaline/caffeine to create his velo, it's a sign the kinetic chain isn't optimized and much of that velo is being generated at the end of the sequence (from the arm).

You can still throw hard this way, (esp. great athletes) but less efficient & sustainable.

Another indicator of efficiency is one's average velocity not dropping off over a game.

Fatigue plays less of a role because they aren't muscling their way into release.

Arm speed created by the center of the body.

This is why DeGrom can average 96 in the 1st and 9th inning.

In summary, we shouldn't just be going for a quick 1-2 mph gain on the radar gun from grunting more or improving our ability to close the gap with our arm.

That's one very small & short term piece of the puzzle.

Optimizing efficiency and sequencing is the major unlock.