"Do you want to weightlift until you have low stamina?"
Yes No
Probably like this. Alternatives on this one would be: ".........until you are out of energy?" or "..........until your stamina is near depletion?" or "...........until your body is feeling fatigue?"
Hmm, I'm pretty sure indivi can come up with something.
Edit: Or maybe what daynen said. "until you're tired". Simple is best.