How best to do repeat bike intervals ?

harringtonp

You are doing a set of 6x3mins or 3x10mins and have access to power.

Do you ?

1) Target the same average for each set
2) Have lower target averages as the sets progress

Anyone understand the subtle differences in benefit between the 2 approaches ?

And assuming you are working to 1) above for any individual interval do you ?

1) Try and stick religiously to your target average interval
2) Start the interval above your target average power and ride below it in the latter part of the interval

dahat

If I'm doing 6 x 3 mins @ 120% (VO2) then I'd expect the last one or two to hit less due to natural fatigue over the reps. I'd still expect to hit 110% or the interval isn't much use to you. A tip I picked from TrainerRoad was to start VO2 at slightly lower cadence then build to 100rpm+ over the interval itself.

For longer reps I'd expect to hit the same averafe and aim for the higher end of the target range each time. This is of course allowing for rolling roads etc.

JimmiesRustled

I'd be the opposite of Dahat. My main aim would be repeatability across the board even if that means bringing the power down ever so slightly so that I can hit those same figures over and over. I'm not saying bring the numbers down so much that it's easy. I'm saying bring them down so that you're just barely able to finish the workout.

I always aim to keep the power where it is. I don't shoot high at the beginning and then just try and hold it unless it's a 1 minute effort. If we're talking 3-8 minutes I sit in and try to be as consistent through the whole thing.

Cadence for me, unlike dahat, I need to keep high. If I start low I just end up fatiguing the muscle too much. This depends on how much muscle you have though I guess. At 65kg I only have spindle legs so I always try to tax my cardiovascular vascular system more than my leg muscles wherever possible.

In relation tof your question about the difference between lower target averages as the sets progress vs the same throughout - if you're working through with a lower average as the sets progress you may very well end up in a situation whereby the workout started as vo2 max intervals at 120% or 110% but due to the number of intervals you're now only working at 105% which would be supra threshold. You're not taxing your system as much as you should be. Granted this is an example of vo2 but applies across the board. If you can't repeat the entire workout at 120% look to lower this across the board. Not everyonesure vo2 max will 120% no matter what a coach tells you. You might be a freak when it comes to vo2 stuff and you'll be up around 130% - 135% or you could really struggle and only manage 110% or so. Its different for everyone.

Taxuser1

Not meaning to have a go but surely if you're not able to complete your set at the required power then your body isn't meant to be doing that set at this stage of your training cycle. This is where heart rate is key. Your later sets could perhaps be looked at in tandem with the load on your heart. Less power, average of otherwise but the heart work out is the same?

Bambaata

The way i read it is your target is ..... your target. If you aim for 120 then you hit 120. If you arent hitting it consistently then you most likely have an over inflated threshold and similarly if you feel too comfortable its time to test again. Key here is consistently, one or two seesions wont tell you much if its close.

harringtonp

Okay. So for

Do you ?

1) Target the same average for each set
2) Have lower target averages as the sets progress

everybody so far answered 1) and I would be the same myself.

If I have a target average for a set I aim to hit that every set (as mentioned above too) and if I can't, I quit. When I quit (which has happened quite a bit in the past) I ask myself was I fatigued going into the session, a little sick (wouldn't start the session if noticeably unwell) or is the target average just a little too high. If I think its too high I then drop it for the next session. On the other hand, if after doing 6x3m I feel like there is a bit more in the tank I try a 7th. If that goes well then I'll consider adding 5 watts to the target for the next session and go back to 6 intervals.

This method is self regulating and you don't even need to know your threshold. If you are repeating VO2 max intervals regularly like this you will be working at the correct wattage after a few sessions. I'm always monitoring HR too and see it increasing with each interval. Once it hits a certain value during an interval I usually know I have at most one more in me.

I recognize that most people try to keep an interval steady but for VO2 I always start above the average and drop below it. The best reason I can give is laziness, it allows me to complete intervals a little easier. This can be seen in the attachment, each 3m interval has an average of 315-317 but after 30 seconds I could be averaging 350, 1 minute 335 and for the last 30 seconds I may be only holding 290 as the interval's average drops to 315. In Carmichael's Time Crunched Cyclist he calls this a PFPI (power fade power interval) and he mixes his shorter intervals between PFPI's and SEPI's (steady effort power intervals) which is what most of you guys seem to do. I've longed since dropped the SEPI's and suspect there is little difference benefit wise between them.

I can never do repeated VO2 max at 120% threshold, 115% is about as high as i can sustain

dahat

In your case would repeated 115% be better than tailing off over the interval?

I've not done VO2 stuff in a while but next time I must track the interval and see how it actually goes rather than looking at end lap avg power.

JimmiesRustled

harringtonp wrote: »

Okay. So for

This can be seen in the attachment, each 3m interval has an average of 315-317 but after 30 seconds I could be averaging 350, 1 minute 335 and for the last 30 seconds I may be only holding 290 as the interval's average drops to 315. In Carmichael's Time Crunched Cyclist he calls this a PFPI (power fade power interval) and he mixes his shorter intervals between PFPI's and SEPI's (steady effort power intervals) which is what most of you guys seem to do. I've longed since dropped the SEPI's and suspect there is little difference benefit wise between them.

I can never do repeated VO2 max at 120% threshold, 115% is about as high as i can sustain

The above is kinda what I was getting at with my previous post. The intervals you're doing don't seem to be vo2 max intervals. I'm not sure of your zones but it seems like you're spending 30 seconds in your anaerobic zone, a minute at vo2 and then another 30 seconds around the supra threshold range. So for your 2 minute effort you're only spending half of it at the prescribed zone if that makes sense.

If you can't hold 120% for 3 minutes then you can't hold it. Look to reduce the value by 5% so you're still working within your vo2 zone.

harringtonp

dahat wrote: »

In your case would repeated 115% be better than tailing off over the interval?

Perhaps you're right, that#s the sort of thing I'm trying to get a feel for. The thought of keeping it steady is even worse than the thought of doing the VO2 session but guess I'll have to try and see how it goes.

When I do fade below the target interval average, I still try and ensure that I am at least working above FTP

Mehaffey1

Repeatedly

dahat

harringtonp wrote: »

Perhaps you're right, that#s the sort of thing I'm trying to get a feel for. The thought of keeping it steady is even worse than the thought of doing the VO2 session but guess I'll have to try and see how it goes.

When I do fade below the target interval average, I still try and ensure that I am at least working above FTP

I may be wrong you would need at least 105% for it to be an effective VO2 interval.

harringtonp

JimmiesRustled wrote: »

The above is kinda what I was getting at with my previous post. The intervals you're doing don't seem to be vo2 max intervals. I'm not sure of your zones but it seems like you're spending 30 seconds in your anaerobic zone, a minute at vo2 and then another 30 seconds around the supra threshold range. So for your 2 minute effort you're only spending half of it at the prescribed zone if that makes sense.

If you can't hold 120% for 3 minutes then you can't hold it. Look to reduce the value by 5% so you're still working within your vo2 zone.

What you are saying makes sense from a wattage perspective. Taking a typical definition of VO2 training (e.g. coggan) as being 106-120% of FTP then 1 minute out of 3 would be outside this range in the intervals shown in the image above.

I'm playing devils advocate but if you look at it from the angle of heart rate and physiological response, fading gets the heart rate high quickly as the initial power is well above the target average. You can see however from the image that even though the power drops to suprathreshold towards the end of the interval the heart rate does not. Instead it levels out. I will have to try SEPIs (steady effort) again for comparison but it may well be that PFPIs has the heart rate higher for more of the interval.

harringtonp

Did the same workout (6x3m at 315W) yesterday but this time kept the power steady (as shown in attached image) rather than fading.

Heart rate probably didn't get as high but there was more lactate buildup in the legs and overall it felt harder. Will do them like this for the next few sessions to see if there is adaptation and then alternate between SEPI and PFPI

Bambaata

Not sure if related and i was going to start a new thread but this might play into the intervals advice. I came across this article today and i think its an excellent read. Particularly like the focus on hard work when fatigued! Ive found ive struggled later in races (i know i work waaaay to hard all race but gives food for thought about doing hard reps when you've already built some fatigue)

https://www.trainingpeaks.com/blog/the-making-of-a-pro-tour-rider/

Anyone doing any rides/sessions of this nature?

Taxuser1

Bambaata wrote: »

Not sure if related and i was going to start a new thread but this might play into the intervals advice. I came across this article today and i think its an excellent read. Particularly like the focus on hard work when fatigued! Ive found ive struggled later in races (i know i work waaaay to hard all race but gives food for thought about doing hard reps when you've already built some fatigue)

https://www.trainingpeaks.com/blog/the-making-of-a-pro-tour-rider/

Anyone doing any rides/sessions of this nature?

I'd love to be an under 23

I'm doing some but it's still January. everything so far is short repeat efforts around threshold followed into tempo. Not quite above threshold. But then that's nothing new really for this time of year? Still building with goals in late April/may