Hello @Sir_Paul! Generally speaking, peak neuromuscular power in humans is developed between 90 and 130 RPM…so quick answer is that NM sprints in FF should be done from a rolling start, for sure.
That being said, the kind of trainer that you’re using, the kind of training that you’ve been performing, and your technique (standing/seated, starting cadence/gear selected, etc.) all impact where you can generate peak NM power. We find that many folks tend to use too big of a gear during the NM sprints during Full Frontal. I usually recommend starting in a gear where you’re at 80-85 RPM at approximately 100% FTP power and then start sprinting without changing gears…trying to accelerate as quickly as possible while out of the saddle.
If your trainer doesn’t have a significant flywheel/resistance then it’s possible that you will spin out the gear pretty quickly. While using a KICKR I can consistently hit > 1000 watts by doing sprints on Level 0 (level mode) in a 53X16 gear starting off at 80-90 RPM. When I do a max 5s sprint in Full Frontal, I still use Level 0, but a 53 X 14 gear and typically hit 1300-1400W for the 5s efforts at a cadence of ~115 RPM.
If you haven’t done enough high cadence training (especially workouts like cadence builds) and/or if your maximum cadence is <150 RPM then you likely have a speed limitation that will prevent you from hitting peak NM power at a “normal” cadence of 90-130 RPM.
Doing a workout like Violator in Level mode is a good way to figure out the kind of gear and cadence necessary to hit peak power…since you get about 64 attempts to get it right 
Standing starts allow for a higher peak torque, but not necessarily a higher peak power (though in the course of a standing start, we often see peak power generated in the last 5s of a 20s start effort since the cadence is getting up over 100 RPM).
Let me know if that makes sense!