Roadie sprinting (waving the frame around) is iffy on fixed rollers. I've been doing some standing "trackie" sprints (bike very upright) at high cadence. That kind of sprinting works perfectly fine and really forces you to be smooth even while standing.
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Cat 2 Track, Cat 3 Road.
"If you’re new enough [to racing] that you would ask such question, then i would hazard a guess that if you just made up a workout that sounded hard to do, and did it, you’d probably get faster." --
the tiniest sprinter