I did today 211 watt @ 20 min during the Zwift Medio Fondo. My weight is 63 kg. And so 95% of 20 min should be: 95% x 211 / 63 = 3.18 W/KG. However, it is listed as 3.1 W/KG.

In fact, that is not the only calculation being wrong, it is on more places I just discovered.
:lol:
:lol:
whats so :lol:
Some riders get DQed or UPGed or WKGed just by a fraction of hundreds. So if you are that strict you need to make sure your roundings are correct or beter perfect. Furthermore it should not be that difficult to get the numbers correct, don’t forget there are a lot of cyclists who take their numbers serious.
The specific column seems to be replaced by w/kg over the whole effort. The rounding is correct :D

In fact, the 95% x 20min value makes no sense for most efforts.
Alexander Perdon wrote:
Tue Jan 15, 2019 3:04 pm
The specific column seems to be replaced by w/kg over the whole effort. The rounding is correct :D

In fact, the 95% x 20min value makes no sense for most efforts.
The FTP calculation based on your best 20 minute effort in fact makes a lot of sense for most event. It's a much better way of filtering out people riding below their true cat.

Think racing over the epic KoM for example... imagine a "cat C" rider pushing 3.6kwg all the way to the top for let's say a round 20 minutes to make it easy. This translates into an FTP of 3.42kwg, well over the cat C limit of 3.2wkg. Now after the climb he goes into the descent for 10 minutes pushing 2wkg. All of a sudden his average power over the ride drops to 3.07kwg... you see where we're going with this?

The 20 minute calculation is imo the best way to calculate FTP for racing, most of the time... I just opened a new topic with an example of a race where the 20min rule does not work, because it's being circumvented by the race only lasting 19m07s.
Reverz wrote:
Tue Jan 15, 2019 8:49 pm
Alexander Perdon wrote:
Tue Jan 15, 2019 3:04 pm
The specific column seems to be replaced by w/kg over the whole effort. The rounding is correct :D

In fact, the 95% x 20min value makes no sense for most efforts.
The FTP calculation based on your best 20 minute effort in fact makes a lot of sense for most event. It's a much better way of filtering out people riding below their true cat.

Think racing over the epic KoM for example... imagine a "cat C" rider pushing 3.6kwg all the way to the top for let's say a round 20 minutes to make it easy. This translates into an FTP of 3.42kwg, well over the cat C limit of 3.2wkg. Now after the climb he goes into the descent for 10 minutes pushing 2wkg. All of a sudden his average power over the ride drops to 3.07kwg... you see where we're going with this?

The 20 minute calculation is imo the best way to calculate FTP for racing, most of the time... I just opened a new topic with an example of a race where the 20min rule does not work, because it's being circumvented by the race only lasting 19m07s.
I agree that 95% of 20 mins would be a better value to judge a rider's cat than average w/kg over the whole effort, but in my opinion this value still doesn't make sense for most events. For me in fact both values are not useful to determine a rider's cat.

Let me explain why. FTP is considered to be your maximum average over an hour and 95% of 20 mins can be considered as a well prediction of this value. However, it is quite important that the effort is steady and your muscles are free of stress of any other previous effort. If you take a look at all courses there is allmost no single part where you can go steady for 20 mins, for sure the Epic KOM not since it is quite irregular, maybe the climbs in Innsbruck can a bit meet up the expectation. Furthermore, at the start of a race most riders will go crazy hitting their anaerobic and vo2max zones for the first couple of minutes. After that it will drop down to threshold or tempo and for sure you won't be able to hit a proper 20 minutes anymore. Therefor, if the race results show that a rider is very close performing to his FTP and he or she does this a couple times in a week I highly suspect the provided FTP value.

If you take a look at my results for example I never go above 3.2 watt/kg during a race. Does this makes me a cat-C based on w/kg. Way no. My actual FTP divided by my body weight makes me a mid-B rider. And why I never hit this 3.2 I explained above. On sunday I was on 3.18 after allmost 2 hours after a week with some heavy load. You will never achieve that score if you are a true cat-C. So in my opinion the 95% of 20mins is not useful to determine the cat.

Furthermore, in most races the absolute power is quite dominant. Or to make it easy, to be able to stay in the pack in cat-B you need to push at least 200 watts in a steady pace. That is already very close to my FTP. Hence I have no chance at all to compete in cat-B, but in fact neither in cat-C since they guys are able to stay in the pack at the start of the race and enjoy the draft when I just simply already got dropped.

For that reason I really favour categories based on racing competence in which you can promote or relegate based on your achievements. So let's forget about w/kg based categories and just look at the bare results in time and position.
I think Zwift and Zwiftpower seem to be quite popular, which might suggest they have something right?
Fozzzer wrote:
Wed Jan 16, 2019 10:59 pm
I think Zwift and Zwiftpower seem to be quite popular, which might suggest they have something right?
Yes ofcourse because it gives lots of fun. But why not try to make it more fun for more people.