To the player that say that he wants to jump, I would just say that, "sure, you spend a couple of hours jumping, what does the rest of you wants to do?" and that's it.
By the way the player will respond: "No, wait! You misunderstood me. I didn't want to jump for hours. Just a single eight meter jump. Did I make it?"
That's still meta-gaming because the reason he wants to do it is to push a skill roll in a safe environment to earn easy WP for no effort, not to jump 8m. If he say that it is some sort of training, then I would say that this game doesn't have that kind of training. In this game you earn XP that you can spend increasing XP. There is a specific list how to earn XP. The only XP question that could be called for here would be
Did you perform an extraordinary action of some kind?
To do a long jump where failure has no consequence is not extraordinary. To do a jump over a 8m chasm is another thing. This calls for a skill roll because it is both very dramatic and is a tough challenge. This chasm jump, I would probably give a formidable difficulty (-3) move skill roll. The Art of Failure is obvious, you fall down. If this is not the end of the adventure, the GM might call for a failing forward if he fails, like he manage to stop his fall a bit down, taking a critical injury, but he is at least not dead. Also worth mentioning here in my example is that if the player actually succeed this -3 skill roll on his initial roll, he can't push it since pushing would have no further effect. In the end of the session I would accept this as an "extraordinary action of some kind" and he will get an XP.
If the player insists of doing a long jump just by the camp with the only meaning of failure is that he only jumps 4m instead of 8m. I wouldn't allow that kind of skill roll because it has no meaning in the game, other than a meta-gaming reason. To the player I would just say "sure, you jump 4m" without any skill rolls or anything or I could even say "congrats, you jump 8m" but I still wouldn't allow any skill roll because there is no consequence for failing. I would also tell the player that if he just plays the game he will get WP naturally.
WP represent your inner strength, your Ki if you will, something that you get when you are pushing yourself to the limit of your abilities or when visiting a shrine, not by doing some exercises just to see how long you can jump, measuring distance with twigs.
It all comes back to the GM. If the GM thinks that this kind of skill rolls are ok, then they are ok. It is not in the spirit of the game, but it is common to tweak and house rule RPGs to your liking. I just told you what the idea of the game is. Change it if you like. It is not a big deal. Personally, I would think the game would be boring because the players would just do nonsens skill rolls during the days back inte a settlement where they can sleep safely in an inn at night until they all have earned 10 WP.