Will has recently discovered he can hop - sort of. He can at least get both feet off the ground for a very small amount of time. Half of the time this results in a hilarious wipeout (hilarious when he doesn't hurt himself of course). When he hops, he also tends to yell the word "HOP!", which helps him get some air I guess.
If you ask Will to do a really big jump, he will get a running start of at least 25 feet, stop, then the jump itself pretty much looks the same as in the video.