TR workouts vs HR zones. i need some help



new cyclist and to TR. finished sweet spot base I with additional outdoor rides. calculated initial FTP at 185 using wattbike app, last 4 weeks were mostly easy. started SSB II low vol with FTP test today which came out at 233. I estimate my max HR at ~182 (TR 20’ FTP HR maxed at ~180bpm). 49 yrs old, 191cm, 98kg.

i understand the recommendations that HR is a poor metric for training and that many users dont use a HR strap. However, at least one of my weeks TR sessions is away from home in a hotel gym. Ive found from experience that the advertised power on other equipment can vary from my home equipment ( wattbike atom), so it would be useful to have approximate HR zones or perhaps RPE for the various workouts.

the second part of my question, in relation to the first. Im impressed with the new FTP though it seems high. I fear i may not complete future workouts at this level, particularly over-unders, even if i can and my new FTP is higher than actual, is there a detriment to the workout sessions if im working harder than intended. ie sweetspot workouts are approaching failure, endurance workouts at too high an average HR over and under reaching max HR.

apologies if this sounds muddled, in essence, im used to HR training when i was a (poor) runner so moving forward to power training with TR i need reassurance that, though hard, if completed, the required training is still effective but what levels of RPE/ HR should i expect for the various workout types.

many thanks



Hi WillyR, I started out doing HR sessions, based on E1 E2 E3 and Vo2 max HR Zones, I converted over to Power a few years ago, first on a fluid trainer (smartless) and have now used a couple of Smart trainers (currently a Tacx Flux 2), One thing I have learnt that if you are consistant with your set up then the results will be consistant, the improvement will be accurate, so if you have been consistant then trust the new FTP. If I was you I would use that away from home session as a recovery or active recovery session and punch out the harder sessions on your bike with Power.
If you have never done a cycling structured training plan before then it is not surprising that your FTP has jumped high, in my case I started around 217 and after running the SSB SPB and CRR was up at 340, I dont believe my trainer was accurate but by being consistant I trusted the FTP adjustments for sessions, I can say I have never felt so strong on a bike in my life and completed some very satisfying cycling goals.


thanks for the advice. im with you on that. heartening to see big increases and yes they would be bigger in the early days. just trying to juggle the TR sessions vs travel. im a longhaul pilot so with rest after a trip just doing the low vol plan means i need to do a quality session away from home.


For a 20 minute test you should not be near your max, you’ll be right near your threshold hr. The old friel test is to take the avg hr for the last 20 minutes of a 30 minute time trial.


as i understand it the TR 20’ test should be done to failure.

“…keep turning those pedals over until you simply cannot maintain target power any longer…”

if thats the case then surely HR would be approaching maximum?


That instruction is specifically from the Ramp Test, not the 20 Minute Test.

Ultimately a proper power test will lead to smoked body, so it’s probably similar overall.


Hi Willy:

You understand the problems with HR? It depends on temperature, your other stresses, your state of fatigue, and all that? And you understand
[a] that HR tends to “drift”, ie at a constant power output, it tends to gradually rise or fall, and
[b] that it takes a while for HR to adjust to a new power output – on your trainer, the power jumps immediately you put more effort in, but HR takes a while to respond.
You get this?

OK, then given that you are often going to be in a situation with inaccurate / no power, then you can go with either rate of perceived effort or some approximation through HR.

RPE requires you to develop an understanding of how it feels to put out 150 watts, 180 watts, and so on. You need to keep notes about your training sessions and develop this understanding. It takes time.

For HR, and recognising that this is really on approximate [because of the caveats with which I opened this reply], you need to go into your TR workouts and establish what is the general level of you HR that corresponds to different power outputs under specific conditions [hot/cold, tired/rested, …]. Of course, given the lag between HR and power changes, you cannot possibly do this for short intervals.

Once you’ve got this relationship [approximate], then you can start a workout and observe the gears / resistance settings that give you the HR that corresponds to the power you are trying to put out. So intervals of > 2 minutes become feasible using this method.

Good luck.