Hello All,

I will appreciate your advice on that:

According to a study I was shown, when one wants to improve VO2Max, sets of intervals in which one goes above 90% of his HRMax is the better way, while an interpretation suggests that the key thing is the total time one manages to stay at such above-90%-of-HRMax.

I personally, when doing such intervals, say of 2 minutes duration each, get above my 90% in the second minute, so for example, if I'd do a set of 6 of them, I'd 'collect' 6 minutes above 90% HRmax.
While - - - in some 2 hours rides, the aggregated time above 90% HRMax is 15-20 minutes, which in no way I can reach by intervals.

I wonder what is better / more effective for improving VO2Max - those intervals ? or such a ride ? (any additional value to short all-out intervals ? )

Thanks a lot !

VO2Max is a complex combination of the body's ability to take in, absorb, transport and utilize O2. While I believe both the intervals and the ride would have benefits to the body I also believe those benefits would be different.

For VO2Max, my bet would be on the intervals -- especially depending on how you do them (and specifically their intensity and duration) because the intervals have the ability to systematically and predictably stress all of the systems and processes that are part of the VO2Max equation.

Conversely, I would also suspect that 2 minute intervals may be barely enough to stress all of those systems -- by the time you get all the systems running at their (near) maximum capacity, you shut them down.

My exercise physiologist has recommended 4 minute intervals for me alternating between 80-82% MaxHR and 95-97% MaxHR. In actuality, I divide the 'rest' period into 2 minute halves: 2 minutes bringing my heart rate down and resting; then 2 minutes (or 1.5 minutes) bringing it back up to 95% -- so my actual interval is actually more than 4 minutes. Actually, my 4 minute high intensity interval starts where yours ends.
... I do 3 sets of them bracketed by a 4 minute 90% interval bookmarked at each end.

During that 4+ minutes ALL of my systems are being stressed to their near maximum capacity and thus building on my overall VO2Max.

Well, that's the theory anyway!
... I'm sure I'll get some push back from those doing 30 second intervals.
....... But, when you change the equation, you change the results.

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Thank you GeorgeBMac !

Interesting.

Firstly, going for 90% of MHR or whatever percent is a bit of a mistake. What you want is to be over your lactate threshold (LT) by some amount, which means first of all knowing where that is. There are tests to find it. Google or use the sticky on this forum. Among those who use power meters to determine the intensity of their efforts there's a concept known as functional threshold power (FTP), which is the power one can produce at or near one's lactate threshold. FTP has been found to be a better gauge of effort than HR because what happens in your legs during an effort starts as soon as you hit them, not when your HR reaches some certain level.

Your HR will always lag during hard short efforts. So say you do a hard effort of only 3 minutes. Your HR may only be over your lactate threshold for the last minute. However if you are holding a steady effort, you will be doing a VO2max interval the whole time, not only the time your HR is above LT. So use your HR to gauge the effort you are supposed to produce, but count the whole time of the interval during which you are holding the effort that eventually produces the desired HR. Note that if you are too tired from other recent workouts, you may not be able to reach this HR and thus should not be doing the intervals anyway.

Elite athletes using what is known as polarized training have found the most effective interval plan to raise VO2max is a set of four 8 minute intervals just over LT. There are many interval plans to choose from. See https://www.bikeforums.net/33-road-bi...cipe-book.html

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Thank you very much Carbonfiberboy.

If a rider does some steady efforts intervals, say 8 of them. The first interval will feel much different than the 4th. and then the 8th is way different and most exhausting as the desire to maintain that intensity starts to wane.

Is there an optimal number of intervals here?

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Sorry I am not an expert so I cannot advise. Guys tend to go for 6*3 min, 4*4 min but I cannot tell if that's the optimum

[QUOTE=Garfield Cat;17890599]If a rider does some steady efforts intervals, say 8 of them. The first interval will feel much different than the 4th. and then the 8th is way different and most exhausting as the desire to maintain that intensity starts to wane.

Is there an optimal number of intervals here?[/QUOTE]

Of course... The optimal number is the number given by whoever you ask -- and if you ask 5 people you will get 5 different answers. And that includes not only number of intervals but also the intensity and duration of each interval -- as well as the rest periods between them. And, it even includes how you measure/determine the intensity...

Exercise physiology is still a very crude science (if you can even call it a science)... And, HIIT training being a relatively new addition to the field, it is perhaps less of a science than most other forms...

That doesn't mean it is not beneficial. But, when you start getting down to the details and nuts and bolts, you end up with a lot of educated guesses... But [heavy sigh] that's the best we have to go on right now...

Personally: my exercise physiologist suggested: 3 or 4 sets of: 4 minute high intensity at 95+% MaxHR followed by 4 minute rest at 85% MaxHR. But, if you change either the duration or the intensity or the rest periods, then you should also adjust the quantity of intervals (and vice-versa)...
... Some people prefer 10 sets of 30 second intervals of high perceived effort.

Perhaps the best general advice is: "Do it till you see Jesus!"

carbonfiberboy's comments are spot on.

You're probably referencing one of Seiler's studies, where athletes apply the maximum effort sustainable for each interval. Heart rate there is just a symptom, and may be lower or higher (the subjects reached 90% +/- 2% doing 4x8, and 94% +/-2 on 4x4).

He also says the heart rate measurements were over the last 25% of each interval.

Seiler reports 4x8 produced bigger improvements in both VO2max and threshold power versus 4x4 or 4x16. As hard as tolerated (for me at 10 minutes that's 110% of FTP estimated from 20 minute power). 2 minutes rest between intervals. In a slowtwitch post he suggested 7-10 minutes.

Intervals. Much longer than 2 minutes. Short intervals will improve your sprint, but aren't the right tool for VO2max.

As many as you can do without an unacceptable drop in power, perhaps 5-6%, ignoring the first one or two where you're extra fresh.

[MENTION=78894]Carbonfiberboy[/MENTION] is correct. It's not the amount of time at 90% max heart rate, it's the amt of time over lactate threshold. The problem with training with HR (as opposed to power), is that heart rate changes slowly, there is a physiologic "damper" on HR, it doesn't change instantly even though your power output might.

Here is an example from some VO2max type intervals that I did this morning. These were 3 min intervals at 115% FTP, followed by 2 minutes at FTP, for a total of 20 min. Power is purple and HR is red. You can see that power changes instantly but HR only gradually. The entire time that the power is within target "counts" towards your desired effect.



As far as what is the "best" interval length, I hear what people are saying. But I think it also depends on your overall training schedule- what you did over the last month, last week, yesterday and what you need to do tomorrow and beyond. There might be an optimal VO2max interval but it might not be optimal for your overall training schedule. Some of that too will depend on age, cumulative training, ability to recover, etc. It's a bit of an art, putting together an optimal training plan.

If you can do those where the 2 min is at FTP it's probably time to raise your FTP.

Lol, you'll have to take this up with my coach.

Seriously, by my calculations my FTP should probably be raised by 5-8 watts, but my coach has not increased it. He 100% knows what he is doing and trust me is completely paying attention. I'm not sure what his rationale is, I've had a number of more pressing things to discuss with him in the time we have to converse. But I'm very confident he has good reasons for not increasing my FTP, I speculate it has to do with being a woman, a master, a newby, an endurance rider (which means lots and lots of pedal strokes) and just completing a series of difficult climbing rides (which meant generating a lot of pedal force). Whatever, I'm not concerned, I'm making rapid gains and already need new cycling friends about every 8 weeks.

"Elite athletes using what is known as polarized training have found the most effective interval plan to raise VO2max is a set of four 8 minute intervals just over LT" would the intervals be above your FTP?
Also "elite" are we talking CAT3 and up or pros ?

Good stuff as ussuall from you

My impression is that those folks were of the medal contender variety. Be that as it may, I tried that interval protocol in my late 50s. It was extremely effective, but also a very large training load for me, so large that just doing one set/week in addition to my weekly hard group ride had me overtrained in a month way back then. So I quit doing that. YMMV. I was killing it for that month though! Then one day I realized as I was riding uphill to the gym for a workout that I was grabbing a smaller gear rather than a larger. Uh oh.

If you can just barely hold that effort level for 8 minutes, you're doing it right. You should be panting hard all the way after the first minute. It takes a little practice to learn how to titrate the pain. And it's all about recovery.

In my case, the social aspects of the group rides were more important to me so I dropped the intervals. If I were training seriously, I would have done the opposite.

At the end of the day FTP is just a number. If you tell your coach the workout was easy, next time he'll make it a little harder by raising the target powers.


I just just made my comment since some people would struggle to do a 20 min workout 9-10% above FTP.

Who said it was easy? And who said it was a 20 min workout? It was just 20 min of those intervals, then 15 min of 1 min-1 min- 1 min at 115% FTP-100%FTP-75% FTP. Plus warm up and cool down. Pretty tough workout, total 1hr 5 min. Love it.

I find almost all of his workouts to be very hard but do-able. He's really good at scheduling just exactly the maximal thing you're capable of on that day. It's influenced for sure by the surrounding days, this is kind of a light week overall for me but because of constraints on my end this weekend, I wound up with three consecutive interval workouts, plus a road ride. So what I can maximally do on my interval days is different than what I might get assigned in a week with two interval workouts for example.

He gets notes on every ride, we talk on the phone, he knows how I feel. I'm pretty comfortable that he has an excellent sense of where I am right now.

I mi agree that the FTP is just a number. A big huge important number from which a lot of training and pacing is determined. But it doesn't capture your entire picture. There is a little more nuance to it, I think. I don't completely understand that nuance. Fortunately I'm not the brains of this operation. My role is to just ride the bike. Fine by me.

I was testing a saddle for a couple hours this afternoon, so out of curiosity I went over to a local hill and did 2 X 8' VT2 interals, all I had time for. The second was faster than the first so I know I had at least 1 more in me, but probably 2 more. Not bad for not having done one in 12 years. VAM was 941 - it's a Strava segment and it takes me almost exactly 8' to get up it, so convenient! Granny gear climb. 20 mph headwind for 12 miles on the way back, drops, 90 cadence, and Friel zone 3. The saddle worked great and only $30! We have a bike tour starting in 4 days, so a good day for a little hard work.

Excellent contributions to the thread. Thanks.
Enjoy your tour!