I don’t think energy is youthful — a lot of fighters bring high energy to fights past their early 20s. And a lot of fighters with power have long shelf lives.
I think energy is about youth when it comes to the high energy of a Tyson. I remember a fighter in the 1980s named Frankie Warren, who fought McGirt two times.. Just had a whirlwind style which overwhelmed guys, yet he didn't look like he could punch hard.. Soon his style wore him out and McGirt won the rematch, a combination of Buddy learning some things and Warren wearing out a bit from that style. That is my take on it. That is all we give on here is opinions, beyond that what is the truth? Tyson to me had this style which after a few years was harder to naturally exhibit, which is why he was hit cleaner later and didn't utilize his head movement in the same way.