L3 and L4 Auto interval selection. - Problem and suggestion.

[Hugh English]

Hi Mark,

I'm having problems with the automatic interval selection feature. Firstly - I love it, in principle its great especially in combination with the sustained efforts, but the current 85% cutoff misses a lot of my intervals as I have a high W' (I definitely have a big Anaerobic engine).

My CP is 275 and W' 42kJ (FTP 288 = 275+42000/3600). I have plenty of max effort data (at plenty of different durations including >30 mins) and anecdotal evidence that supports this within a handful of watts on CP and within 2 kJ.

I put CP into the CP box not FTP, but train with Zones based off FTP (which makes the GC zones wrong - I could edit them manually I suppose but not sure that'd make much difference to this particular issue. I'd like to see both a CP and FTP box, with whichever you don't enter calculated off W' - for a long effort, 13 W is quite a big difference!) .

Problems arise when doing L3, and 4  intervals that they often don't register as 'Efforts', as my best (both tested and modelled) efforts for common interval durations are well above my FTP. Anything more than a few watts above CP seems to be ok, as some W' is burned up and I get a 'Match'. Sweetspot intervals are the worst offender... see below.

20 minute Sweetspot interval at 90% FTP (259W)

20 minute best (CP model) = 310W = 275+ 42000/(20*60) (Actual best 311W)

85% of best = 263W... so my 259 doesn't register.

Often do 3x20 Sweetspot in winter, but can't get it to register as an effort.

With 5 minute repeats - I need to do at least 4 to get a worthwhile session in, but I can't do 4 at the wattages required for the interval to register.

L3 - I've never had a deliberate L3 interval register despite plenty of 40-90 minute efforts at c. 85% ftp. I had a single 1 hour L3 interval appear from early this year during a training ride more by luck than judgement it appears.

So.... what can be done? I'd much prefer that efforts were detected by reference to FTP or CP and duration rather than a best effort. Perhaps something user definable like.

L3 effort = above 80% of FTP (or CP?) for a minimum of say) 30 minutes

L4 effort = >90% FTP for >8 minutes (I know plenty of people do 4x8 at FTP)

L5/6/7 intervals seem to get picked up well because of the W' expended.

If not this, then maybe the ability to user define the lower cutoff for an 'EFFORT' to below 85%?

Or will user redefining my zones to be off FTP not CP solve my problem?

I'm sure there are people out there with higher W' than me who'll be experiencing the same thing.Thanks for reading.

Hugh