Hard-start FTP intervals

I have heard of and have read many exercise physiology blog posts about hard-start VO2max intervals, but I recently came across the concept of the “hard-start FTP interval”.

For example, do 30 seconds to one minute at about 120 or 130% of FTP, then settle in for a further 12 minutes at between 95% and 100% FTP.

Obviously, there is much overlap (about 12 minutes worth in this example :slight_smile: ) with the standard FTP intervals, but what incremental physiological adaptation would be pushed by this hard-start FTP interval, all else equal?

Would this be something that could improve lactate buffering and jamming it into the Krebs cycle?

“Mental” training for road race attacks where you have to go very hard but then settle into a pace that’s still not really sustainable?

Or would this maybe increase VO2max via a faster way of getting to the slow component?

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I’d be interested to see how others approach this.

In my base (10-15hr wks) I do 3x8min with 5-10min recovery between (1x or 2x per wk depending on other loads). I do the first few minutes at ~120% FTP and then drop down to ~105% FTP. I usually end the 3rd interval at 95% of max HR. I look at both HR and power at around the 4min mark to fine tune the effort on the fly (knowing I’m shooting for 24min total time). For these fast starts I’m interested in getting my HR up quickly and hit the target (energy system, time, HR, metric). For me, it’s less about being race specific and more about making it a higher quality session… I only get 40-60min of high intensity per week, so I need to make the most of it.

That said, I think a lot of folks like 4min intervals for “VO2”. To me, fast starts and/or fast finishes within shorter intervals get into pretty high %FTP. I prefer doing 40/20s instead.


Hard start intervals definitely display some benefit. I did it regularly during my running days i.e. prior to XC races or competitions in general. Lactate goes up, but the body adapts with good lactate clearance, reusing lactate a s an energy source.
I didn’t use a heart rate monitor for that, it was first minute almost all out, then holding a high pace for a couple of more minutes.
So 120% FTP interval makes sense if you are a racing cyclists - that’s what happens in races.