Nacho Beristain: Marquez doesn't have the speed!

[the inbetweener]

Another good example of how speed is retained when moving up weights classes might be Roy Jones Jnr. He refused to use weights.
Instead, it was all push-up's & sit-up's.

He only touched weights for the 1st time when moving up to Heavyweight.

I'm not entirely convinced Roy Jones never did any free weights. But if he didn't, you don't get that physique (see below) without some kind of resistance training. Most likely bodyweight stuff. Pull-ups, dips, press-ups, body weight squats, pistol squats etc.