I noticed as well on the V3 that some characters are just naturally good at bump no matter how much they weigh. The ones I obviously noticed was teketchi's and the one that looks like a samurai. Can't recall the name. I noticed they're really good with bump and sprint.
That samurai guy tries actually be sumo wrestler, I think. The name's Sekitoritchi
And as you know sumo wrestling is mostly pushing each other off the arena, it's logical that Sekitoritchi is naturally skilled in Bump.
Just like Young Mimitchi and Mimitchi have fast response in Heading game. They are "sort of" rabbits