Power Intervals - 4 x 10 vs 2 x 20 vs 1 x 40

[Toolish]

I have been working on doing intervals at 90% of FTP. I am training for long course triathlon

I had been working up doing 6 x 4 min with 2 min rest and things like that. The other day I decided to just hit the wattage and stay there as long as I could. I ended up doing 40 minutes straight at the goal wattage.

I have read in various places that spending as much time as possible at around sweet spot intensity is a pretty good off-season plan for triathlon, and everywhere I see recommendations of 2 x 20 workouts.

It got me wondering, is there any reason to do 2 x 20 rather than just do 1 x 40, or go the other way and do 4 x 10? Ithe end the TSS of the ride would be the same and the training effect very similar wouldn't it?

[vander]

The answer is 6 and half a dozen. There is no precise way to do it as long as you are increasing something. Most people try and extend either interval duration which is a progression like what you have above. Or total time at that level eg 2x20 > 3x15 >3x20 > 3x30 etc. The last way is to increase the intensity whether that is by riding (AT) 90% of FTP and increasing that to 95% of FTP or by going from 90% of 270W FTP to 90% of a 280W FTP. They all work some better some worse for some people. It also depends on what you are targeting.

If you are targeting an Ironman I would suggest upping the total time at that level and upping the interval length. However if you are targeting a sprint triathalon you will probably get more out of upping the intensity.

The reason (I think) 2x20 is used is that it is long enough for the required adaptations but short enough for people to be able to handle it mentally. Dont be afraid to try different things.

[toolonglegs]

90% of FTP is Sweet Spot isn't it?... you should be holding that for long periods 30-60minutes.
96-97 to 103-104 % FTP are more you standard 20 minute bread and butter.
110-120 % FTP is VO2 level 4-6 min stuff.

Longtime since I used a power meter though so I could be way off

[Alex Simmons/RST]

It got me wondering, is there any reason to do 2 x 20 rather than just do 1 x 40, or go the other way and do 4 x 10? Ithe end the TSS of the ride would be the same and the training effect very similar wouldn't it?

Similar, but IMO there is more training stimulus benefit from a contiguous effort than splitting it up (ceteris paribus).

That does not mean you should not do such work in shorter intervals, as there are other benefits to that, e.g. might be more suitable for your training terrain/roads, safety considerations, can help mentally when on trainer or a chance to have some saddle relief and so on.

[ausrandoman]

I do 2 x 20, 3 x 15 or 4 x 10 depending on the mood I'm in and road conditions. I find that the rest period between efforts makes a difference. Five to ten minutes recovery is enough for 4 x 10 but I need ten to twenty minutes between 2 x 20.

[ljk11]

Quick question,

due to location and time I do 3x14's on a little hill near where I live.

When aiming for FTP, should the entire interval be done at the target power or is it ok to finish the last 100m with a harder effort or sprint ?

thanks,

L

[filip]

As it is only 14', i would do the first with the last 3' a hard effort - this will bring your average power for the interval up. The next 2 intervals you should target this new average.

[filip]

or maybe power up the first 1' and then settle into ftp number for the rest of the climb. it makes you train for attacking at the bottom of the hill and to stay away. Very though interval though. i wish i had a hill like that in my area.