How does pumping generate speed?

Hi all, first post!
So just a quick question because I couldn't find it on the internet.
Can anyone break down how pumping generates speed? The question came about after purchasing a surfskate which is yet to arrive, I don't often pump whilst in the water and even then I only do it because I see other folks doing it. Most of the time I'm too busy concentrating on other things while up on the wave, but I don't take to pumping because I genuinely don't understand it and a couple of friends are in the same boat... don't even get me started on Foil surfing.
So can anyone break it down for us? Even use the dark art of 'science' if you have to, to explain how pumping works.
Cheers guys, stay safe.
So just a quick question because I couldn't find it on the internet.
Can anyone break down how pumping generates speed? The question came about after purchasing a surfskate which is yet to arrive, I don't often pump whilst in the water and even then I only do it because I see other folks doing it. Most of the time I'm too busy concentrating on other things while up on the wave, but I don't take to pumping because I genuinely don't understand it and a couple of friends are in the same boat... don't even get me started on Foil surfing.
So can anyone break it down for us? Even use the dark art of 'science' if you have to, to explain how pumping works.
Cheers guys, stay safe.