Originally Posted by
DaveWC
Two things... a 5mph wind is not a wind. It's a calm day IMO. So yes, take wind out of the equation for a flat day and avg speed tends to be consistent.
But no one says that avg speed is an inaccurate measure. It's very accurate. It's just meaningless. My best avg is 22.6 mph but it doesn't mean anything. It's irrelevant and can't be compared to any other rider on any other course for any other day. It doesn't mean anything to me other than that I had a lot of power that day. My avg power/ NP was 307/315w and that is something that means something. I can directly compare that ride with my ride from yesterday into/with the wind where I averaged 275w and determine how well I did, whereas I would come to a completely different assessment if I compared the 22.6mph with the 18.8mph from yesterday.
I also can't determine any type of training program using average speed. It's just an outcome, a result of how I did given the conditions. But given that conditions change from course to course, day to day and with the weather, it's an irrelevant outcome that can't be compared to any other outcome and provide any meaning.
Disagree that the meaningless speed number is useless. If you ratched that number up in the right conditions (meaning not 30mph winds one day, 0 on the next), on the same course, you're improving.
You could say the exact same thing about TrainerRoad's virtualpower. It's an awesome training metric, allowing you to precisely and reproducibly get an objective read on YOUR effort, even if it's not truly equivalent to a real powermeter's output. YOu can't compare it to anyone else, and it's only good for you, but as long as you obtained that number through the FTP test (like the 2 x 20 all out), you're good to go using that very number on the rest of the workouts which dictate what % of power to target.
Again, for the rest of the peanut gallery, if used judiciously, avg speed is a pretty good metric IF USED JUDICIOUSLY, particularly for repeated solo time trials on your favorite training course.Training by power is still much better if you have access to it as it can help equalize many of the variables. Still, if we're dealing with extremes, you can imagine comparing a 80 mile climbing ride in Death Valley at 120F versus an 80 mile ride with same elevation profile in perfect 55F riding temps. Even your powermeter will show dramatically lower power for same perceived effort on the Death Valley Ride, but that doesn't mean the powermeter's not useful, it just means you're not using it in the right context.
And a 5mph wind is still a 5mph headwind. You're cherrypicking the extremes by not posting examples of how your avg speed barely differs if the wind speed is +5 or +10mph different, but only posting +25-30mph wind speed differences.
And again because it keeps coming up, I still train with power, and not by avg speed now that I have a powermeter.