I’ve been riding for almost two year. In order to get my training more consistent and my form better I bought a powermeter and a HRM. I just discovered intervals.icu, it looks great as a starting place for my power data and to follow up on my evolution. David, thanks a ton for making this free to use! If I keep using it, I’ll certainly consider a donation.
I just synced everything from Strava. But only the data from the last week contain power & heart rate. The rest contains guestimated strava power. Is it best to delete all those older activities? And how can I do that in bulk? Or do I just add more rides and will intervals.icu get my current form sorted by itself?
Intervals.icu will normally not use estimate power from Strava. The Strava API doesn’t give that out actually. Was the power estimated by your trainer?
Any as Kosio said I wouldn’t make any changes. The fitness impact of those old activities will disappear from your stats over time.
There were no power estimates from my trainer. I do have a trainer that is way too low in higher power readings (Elite Suito), but that’s something I’m trying to get sorted. Initially by riding on the trainer with the bike with PM and using that as power source. But also communicating with Elite to get the trainer calibrated to my PM…
I’ll keep riding and learning how intervals.icu works in the meantime!
It’s only of general interest anyway, and only with respect to the overall average of an activity.
Provided you perform a ‘round trip’, i.e. leave from and come back to the same place, the overall estimate isn’t all that bad.
Unless the wind turns halfway… Strava doesn’t take any external factors in consideration, it just uses an estimate based on general ‘rules of thumb’ to estimate your power based on your moving speed.
Riding 15 mph into a strong headwind, will estimate 100 Watts, while returning the same way, moving at 25 mph assisted by the tail wind, will estimate 200 Watts.
Or whatever - I don’t know the exact numbers…
The average of 150 Watts is usually not that far off, when compared to data from a power meter, assuming you go with the flow (wind) and do not actually also push harder while returning, perhaps to set a PR or something.
Not sure if I should make a separate thread for this one, just another beginner question.
There’s a problem with my race bike, so yesterday I took the gravelbike for a ride with a (well-trained) friend. When I compare the training load of that 118k flat-out ride yesterday (186) with the load of an really easy 105k on Tuesday (187), something is clearly not right.
Average speed 27,3kph vs 33,8kph, avg HR 136bpm vs 174bpm, distance 105 vs 118.
I would expect the training load of my last to be double that of the first one (felt like triple the load actually), although I’m not familiar with training load calculation tbh…
Most crucial difference is obviously that the first ride was with HRM and PM, second only with HRM.
I spent considerable time around 220bpm, which is above my lactate treshold for sure, based on a max HR of 236). Anything I can change in my settings to get the load more in line with the HR data? I hope to have my racebike with PM fixed asap. But when I ride gravel, I use the other bike anyway, so it would be nice is if the training load based on HR was a bit more reliable…
As to the load: there may well be a difference in calculation if your normal rides are with, and this one is without a PM. However, that would normally not account for such a difference, but @david is the guy to explain this…
On Strava, your ride shows wild jumps in HR that cannot be explained by the change of pace (speed) or terrain (it’s flat). It jumps from 140 to 220 instantly, or the other way around - it may get ‘stuck’ when it is spiking, I’ve seen that on mine sometimes. Also in the low spectrum, where I am blowing up, but my HR monitor is stuck on 85 bpm…
If you take those out of the equation, your average HR is still higher than the Tuesday ride, because of the higher pace, but depending on how much you drafted off your buddy, not that much higher.
Furthermore, Strava calculates an estimated 313 Watts NP for Sunday’s ride, against a PM based NP of 189 for Tuesday. Obviously, had you used a PM on Sunday, your NP would have been (a lot) higher, but I do not think you can produce over 300 Watts for 3 hours, or do you know you can?
Your Zwift race in between had a NP of 270, but that was only 28 minutes. Also that activity shows a weird HR spike halfway btw.
Maybe your HR monitor is acting up (batteries, poor contacts? Which HR monitor is it?) and maybe intervals.icu takes out the spikes when calculating load on HR based activity.
Still, your Sunday load should be higher than your Tuesday load…
I’m a bit surprised myself about my HR… Never have been sporting seriously before I started cycling two years ago, so never wore a HRM. At 44, that max HR looks really high, but apparently there is a broad range of max HR in the population. I’m going to have a lactate test in a couple of weeks to determine my power zones and heart rate zones.
The guy I rode with yesterday has a max HR of 175. And is in better shape. In the longer blocks of high HR (>220), we both took turns, until I was too slow for him and I staid in his wheel for as long as I could cope. I’ve asked him a couple of times to get back to endurance pace to let my heart rate drop to about 150 for a couple of minutes. Then we went full on again.
and here with interval zones of about 220bpm - in blocks of 12-16min, which seems to be how long I can go at this pace (bpm and time depend a bit on where you start the interval of course).
At 44, if you indeed have a max HR of 236, I’m pretty sure that would be a medical miracle I’ve recently underestimated a guy’s claim to have a FTP of 70, but that apparently is possible too
I’ve always assumed that a human HR will max out at 220, which is also the base for many ‘rule-of-thumb’ max HR calculations of 220 - age (so, ~176 for you).
PS And you can see the wild HR variations/jumps in your screenshots - that’s not normal.
PPS. I’m nearly 60 and my max HR is 174, so 220 - age is not science. Also, I’m not untrained
just read you other post… Thanks again for your time. I use a viiiiva HRM, it’s supposed to be good, but there can be some faulty data in there for sure. I analysed my first ride with HRM and it goes up and down quite fast. The further in the ride, the harder it is to get it down apparently…
These are 5min from my first ride with HRM and PM. Full on sprint on a short 38m altitude climb (with some turns as you can see from the cadence)
HR goes from 150 to 236max and back in 5min. If the HRM was wrong, that curve would probably not as gentle as it is? But definitely high enough to get a test to check if all is well.
The 220-age only gives you the median value of a bell curve with a really wide spread. With my max HR at my age I’m probably @99,5 of the curve. But until proven wrong, I’ll assume that both my HRM and heart are in good health
The zone with the spikes was where we changed course as we were in the middle of heavy showers. My mate was looking for another route, so we stopped frequently, then went full out and stopped again to find the way. So GPS went to pause and restarted with a lower HR maybe? Maybe I had a bad contact too as in one instance it seems to drop to half the rate and then back up. But that’s the only place I can find in which the HR data don’t match what was going on on the road.
I can’t ride @300W for 3h for sure. Last FTP test was about a year ago 333@ 20min, so about 315 FTP. My sprint values are my strength, so an actual FTP test over 60min would probably be lower. I think now it should be around 300W. At full speed, I think my friend has done around 60% of the work and I was in his wheel. So NP should rather be around 260W I think. Maybe 280 for the 90min in which we went full out.
Re: the trainer ride. I bought a new trainer (Elite Suito) and tested it against my PM. Above 200W the trainer reads too low. At 750W on the trainer, my FSA powercrank showed 900. That ride was also the same day I rode 105k in the morning, so legs were not really fresh for a zwift race… So not really representative.
Since MHR’s seem to be distributed by Mother Nature along the lines of the Standard Distribution Curve, only the very few in the population who are right on the mean with MHR’s that can be predicted by the 220 minus age formula. It also seems that folks who are one Standard Deviation from the mean will find a difference of plus or minus 12 bpm’s from the mean. And, trust me, in my career I have counted hundreds of HR’s that were as high as 250 bpm’s for people who are down near the bottom at the positive end of the Bell Shaped Curve.
Anyway, hope I can keep that HR controlled and that FTP up! @david any suggestion on how to optimize training load would be great!
Well, I can’t tell for sure how accurate that monitor is, nor whether or not your max HR is that high. If so, it’s exceptional, despite the mention of ‘hundreds at 250’, without mentioning their age and sportive level.
Also, he does an educated guess of a max HR of 195 bpm for a guy feeling ‘relaxed’ at 175.
You feel relaxed at that HR? If so, well…
Anyway, if you get the chance to get it verified, then you will also know if your HR monitor is okay
I think your HR monitor is acting up a bit as @Cyclopaat suggests. If you look at “time in zones” for that ride you spent 66% of the time in Z1 which isn’t likely for a tough ride.
I think the heart rate zones calculation might not fit my heart well… I’ve just change my lactate treshold (214) to fit my max HR (236) exactly. Was at 221 - 240, so too high.
That helps with the zones already. But my recovery zone is still way too large I think. (0-172)
Early in the ride, we rode a long straight segment next to eachother at 34kph. This is from my friend’s strava:
Almost 200W. I had a average HR of 154 on that segment - probably for +200W (he’s a bit smaller and has more drop). I’m not fit enough to consider that recovery… That’s middle of zone 2 in the power zones. Are power and HR zones supposed to correlate?
This is Strava’s Relative Effort (based solely on heart rate) for those same activities. Max HR in Strava is 236 as it is here. 4 times higher for this ride vs last week. While in intervals.icu it is about the same in effort. Other HR zones calculation (based on TRIMP by Bannister) with very different results!
I’ll try to borrow a HRM from a friend to see if the HRM is the problem. Lactate testing and more precise determination of HR zones might help as well to finetune load.
I know this is a tool for power and intervals and you are still working on implementing HR more consistently. I hope this sort of extreme profile can give you valuable feedback!
BTW, the exact same is going on the in the Friday ride. 45km at 35kph average solo ride. Really had to work hard here. Most of the (what felt like) tempo work here is around 150-160bpm. So power zone 2-3, HR zone 1.
Load is 35% of the 120k LSD ride. Relative effort is 142% of the ride. So difference between both models is a factor 4 here…
This is interesting. My max HR is nowhere near yours (188) but 150-160 is where I am at riding tempo power. The “time in zones” load estimation model might work for you but you need quite a few rides with power and HR first.
Ok! So the algorithm will recalculate my HR zones over time to match my power zones? That’s great!
I have a mechanical problem with my PM bike that I can’t fix myself unfortunately… and the bike store has just reopened after the lockdown, so it will probably take a while to get it back…
Thanks for all the feedback. Will get back to this after the tests!
I’ve recently underestimated a guy’s claim to have a FTP of 70, but that apparently is possible too 
