Since it seems to be that time of year. Let’s disregard the discussion of whether it’s your hour power or your MLSS or something else.
Let’s hear what people use their FTP number for in their training.
Me, I use it to scale a set of workouts I call threshold. I work at a range of percentages around the FTP number. Might I be able to optimise it if I knew the FTP number matched MLSS? Maybe but I don’t test lactate so I stick with the functional side of it on the basis it’s good enough.
Do I use it to scale my endurance workouts? No
Do I use it to scale my VO2 work? Used to, but not any longer.
Same, except I do still use it for the above threshold work (not the short, all-out efforts obviously)
eta: I started using power in the last year to add more structure, and because I was having to do almost all my training indoors due to too much job work, so felt the need to track power numbers in the progression. I’ve used HR only for several years, but there is significant difference in my HR from inside to outside (mtb) relative to perceived effort, and the HR lag at higher intensity wasn’t working for me. And, it was the higher intensity work that I needed to work on (consistently) since almost all my previous was outdoors and offroad, without power to guage (i.e., too much high intensity has been an issue for a long time). So, using the ftp to help me set relative limits, has been very helpful.
My power curve fits right in the middle of the normal distribution of riders, so i can use it to set endurance, threshold and vo2max workouts.
65% of my ftp is lactate inflection point. So i stay below that for the vast majority of endurance work. 75% of my ftp is +1mmol over baseline so is the barrier between z2 and z3. 105% of ftp is right around Cp, so a good barrier between threshold and suprathreshold. 110-120% are good numbers for vo2max work but on those workouts i dont care about hitting the power target with precision but use the target as a starting point.
Coggan’s zones will be pretty good for about half of the people out there, and for me are spot on, except for the z1/z2 barrier. There’s clearly a difference in metabolic strain below the first inflection, so not sure if that was the original intent of his z1 or not and he went on the low end for it to be appropriate for most people.
I spent a few years trying different things out. Scaling workouts based on 1 hour power as seiler had been suggesting was not effective for scaling workouts as it made them too easy.
Threshold, Sweet Spot, and Pacing (Pacing on certain rides / races - e.g. racing Leadville this year, will absolutely have power targets and maximums based on my FTP for different parts of the race)
Not for endurance. Moving away from it for V02 Max - just figured that out / learned that recently. I might use high level %FTP intervals to get me in the ballpark, but those are more heart rate / RPE based on different ends of the spectrum.
I nowadays make use of Trainerroads AI FTP detection (which seems to pretty spot on!), by design once a month. I use that number to build my workouts, to build a monthly 4-week plan and to measure my improvements (or deterioration ).
Using it like this, it’s very important to use the same measuring device/test all the time, consistency is crucial.
I use it for whatever TR does with it. I suspect as an estimation of my LT2, it’s an overestimate, as generally threshold workouts are killers – my last base block I managed 5.0 but failed 5.3, then TR backed off to 4.5 and I failed a 4.8. But if I set my TR FTP to a much lower number, the VO2 max and anaerobic workouts would be easy.