AC intensities

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by Kermithimself

Had a discussion earlier with a cycling friend. We talked about AC intervals. He said that 30 second AC intervals should be done at 200% of FTP. I relied on Allen/Coggans 121-150% guidelines, which would say that 150% would probably be the most likely for that duration.

What's the verdict here?

If I was to ride 30 second intervals I would try to stay as close to the 150% mark, not going much over, but I read some other places that the 121-150% is average. So if you start out at 200% and fatigue kicks in, you'd probably land around 150%, but much of that time would have been spent above and below the AC intervals. Correct?
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by Weenie

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by devinci

not quite

it's not black and white like that. If you average 121% for 1 min you still do plenty of aerobic work.

It depends quite a bit on what quality you want to work out. Anaerobic power? Then I would simply go pretty much as hard as possible with using long rest periods. Something like 30s or 1min efforts with at least 5min inbetween. On the other hand, if you want to work out your hability to crank up some high power efforts repeatedly, then I would either work arround some 20s-1min efforts with shorter rests periods arround 1:1 or 1:2 work/rest ratio. The later would turn out being mostly aerobic work after a few repetitions while the former would draw more on your anaerobic glycolitic energy system, with long rests allowing for anaerobic energy system to restore itself partially at least.

It depends a lot on how you manipulate your variables and what's your goal. FOr exemple, I use a workout often described here: 2x4x30s/30s. I use it mostly during winter time and I average arround 175% of FTP for each 30s efforts, yet the overall workout remains mostly aerobic given the short rest durations.

There's a significant difference between going out and hitting some 30s at 150% of FTP or going out and hitting 4-5 x 30s at whatever you can sustain for that period, on a fatigue point of view.

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