[As Hulk, Bruce has a lot of agility and strength, able to catch quickly falling objects in midair with only a single jump. But as Bruce Banner, slowly aging scientist, the only thing he's got on his side is a very nice pair of legs, toned from years of running.
Which is what he does now, sprinting towards the spot where he thinks Kitty might land. He's not sure if he'll be able to catch her, but if nothing else, he should make a nice cushion to land on.]