Eh, water off a duck's back, just let it roll.
My old guy, Banjo, was MASSIVE. Tall and long with a chest that was equally impressive. He wasn't nimble, not to say he wasn't blindingly fast in some respects, but the smaller framed GSDs of friends could make him look silly when playing. He had a nice topgear, but needed some real distance to catch back up to the better proportioned dogs.
My female now, Allie, is on the small end of the scale. Just nudging 50 pounds, great leg length and overall structure. She has some serious leg muscles too. She can cut and run so easy, she makes daredevil moves look like she's gliding on skates. She regularly makes my bigger male, Cable, look like an idiot when they play. Cable is stout, compact and heavily muscled. He's in the lmid 60s weight wise, sorta stubby legs with a big beefy thick chest. He's easily twice as powerful and Allie still makes him look like he has 4 left legs.
Going from my old freakish mutant gazelle with canines to these more svelte dogs has made me appreciate the idea that the smaller ones are the sports cars of the breed. They move more easily, with more grace and can do some pretty cool acrobatics when the mood strikes.
Never cook bacon while naked.