Look at some of the clips under
or if you prefer quality (youtube sucks) :
I'm an Aussie wave sailor, who's temporarily living in some Godforsaken, land-locked place in North America. I consider 95% of boardsailors don't live within cohees of the warm waves of Hawaii, Bali and Sydney (home). In them's lakes and rivers and coastal waterways, wind is flaky and seasonal, wind chop is not jumpable.
I sail and freestyle longboards 'coz it keeps me fit. I don't use a harness so endurance. As you can see on videos, I push as much as I pull, so biceps and triceps. Dorsal and abdomen. Probably trapeze and deltoids, if I knew which is which.
It's cheap - the board in those clips cost me $25 - not a joke - in a garage sale. I sail that old gear from about 15 km/h to about 30 km/h. Yes, low wind is less eventful, but with freestyle I find things to do and shins to crack. I can prepare higher wind moves. Lotsa sailors just sit on the side, wait that the wind picks up all day, and trade incredible (really) war stories - I sail. I don't need a windmeter device to know which sail I'm gonna use, as I have only this one.
That kind of freestyle can be done on so many boards, Starboards, Konas, many non-rail moves are on shorties (110L), and so on. And once on a closet door.
When I do return in Australia, I'll be in the waves and then will carry more, fancier, more expensive equipment. I'll still have a longy to fart around for the rare low-wind days.