Question about Power Intervals

Azikara said:

....OK, here's my problem: I cannot do the 2 sets of 3x3 min PI (Power Intervals). Chris describes these as being "all out" efforts. To get through the 3 mins feels like 90% to me. That's the only way I can get them done. ...

"All Out" has to be taken in the context of what you're trying to accomplish. No athlete can go "all out" for 3 minutes during VO2 Max work or 30 minutes during Threshold work if you define "all out" as a full sprint or your best 1 minute effort.

All out for focused interval work basically means a level that's difficult but still allows you to finish both the individual efforts and the overall session. If you blow up after two minutes or can't finish the entire set then you're going too hard. In power terms classic VO2 Max efforts like those you describe are typically performed at 110-120% of your FTP. Heart rate won't work well for intense shorter efforts like VO2 Max because your heart rate just takes too long to respond.

Without a PM, your best bet is to tune into your perceived effort and if you do these on a trainer or on a consistent course like a steady hill then you can watch speed as a proxy for power. But however you gauge your efforts, you want to hold back just enough to finish each effort and the overall session. It definitely shouldn't feel easy and should take a lot of focus to dig deep and finish VO2 Max efforts but you need to finish.

Good clues on proper pacing are getting to maximal breathing at roughly 2 to 2.5 minutes into each effort but not much earlier but you definitely want to hit maxed out and ragged breathing during each effort. They're VO2 "Max" efforts after all so you'd better be exchanging "Max" O2 before the end of each interval.

BTW, this is a great example of the ways that power measurements assist training. HR just can't respond fast enough to gauge VO2 Max efforts and descriptions like "all out" are subject to interpretation. But power targets for each effort like 115% of FTP clearly define the target intensity level.

Good luck,
-Dave

Dave,

Thank you very much for your insight. I did exactly this last night and got through all nine intervals. They were tough and I did have to dig deep but I finished.

Agree totally on the HR comment for these types of intervals. Hopefully the PM will arrive shortly!

Thanks
Azzy

Hi Azzy,
I am also doing Carmichael's workouts using a HR monitor. I agree with Dave: a power meter would be WAY better. That said, I can do PIs without power, using HR and perceived effort. I start my PI like I would start a time trial, though usually from 15 mph as opposed to a standing start. I ramp-up the effort in the first minute or so, so that I don't start hyperventilating or build-up too much lactic acid. From then on my PI is all about perceived effort: I go as hard as I think I can go for the duration of the PI, and toward the end I just keep trying to go harder. My HR usually takes over a minute to go from what is usually an initial 110 bpm to my target of 170+. My HR will increase linearly over the last 2 minutes of a 3-min PI, and sometimes I am able to kick it up just a bit more at the very end (perhaps suggesting that I could have been going just a touch harder?). The HRM is only helpful for me to look at my interval workout afterward, to look for consistency in the repetitions as well as for the general "shape" of the peaks.
I find OU workouts to be very difficult to do properly with only a HRM because your HR's response time--relative to, say, your power output--is so slow. I find it best to use the HRM to get a feel for the perceived effort of the Over and Under portions of the workout and then go by "feel".