I'm on board with suspension of disbelief, for the most part. There is a point where that can get strained, even within a fantasy context, but I'll wait until I see the film.
I *have* seen some real-life, heavyweight fighters move frighteningly fast with deceptive agility; they just can't move like that for long, necessarily.
The idea being they don't have to, given their devastating firepower.
I'm going to assume Bats has maintained himself in peak physical condition. As an amateur athlete past his prime, I can tell you that power increases in your 40s, but speed decreases while recovery time and potential for injury increases; prep time increases as well.
Experience makes up for it up to a point. Your mental game and pain tolerance is very high, but age *will* tell on you, sooner or later. Yoga helps.
Batman has money, time, talent and obsessive drive so I'll give him a slower rate of decline than most. And I bet he does Bat Yoga.
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