4.2 w/kg ftp = 4:30 mile time. don't ask to see my math.

The times that I was up at 4.2W per kilo last winter I can assure you that I was no where close to 4:30 mile speed. My best mile speeds in the past 10 years have not been sub 5:30 and my all time best was only 4:42 (albeit for a 7:06 1.5 mile fitness test in college). At the moment, I'm limited by Orthopedic issues from running faster, but not limited by orthopedic issues while riding at FTP type paces.

inquiring mind.

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http://www.truckeecyclocross.com
California

The faster I climb, the faster I run (no rocket science).

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http://www.truckeecyclocross.com
California

LOL...thanks for pulling up this thread from 2011, but I think on Mont Ventoux that's what Chris Froome thought about and went back to his high school middle distance running days and just kept going at 6.25 W per kilo but this time running.

(Directed to no one in particular in this thread.)

The notion of "running power" is antithetical to many classically-trained biomechanists - at most, they will admit it exists, but is small. I can see their point, but if you define it as "the rate of performing work against the external environment", then clearly it exists. Defined as such, however, mechanical efficiency is significantly higher than observed during cycling - in fact, it can be "impossibly high", at least compared to the efficiency of muscle contraction. This is because the environment also does work on the runner, with this energy being recycled via the series-elastic elements of muscle. In essence, this results in a form of double-counting, and hence an elevated efficiency.

Anyway, my point is that although there may be a modest correlation between cycling power and running speed, you can't accurately estimate running power from speed by assuming a comparable efficiency.

For experienced runners, running effectiveness, I.e., the ratio of speed (m/s) to power (W/kg) on level ground is around 1 kg/N. So, all you would need to do is convert the Vdot paces into speeds.

Thanks Andrew....on the "double counting" are you referring to the compression and subsequent rebound? But on the other hand you have a phase of the running stride where zero work is being done (runner is floating in the air and getting ready for next stride). But in cycling, rider is continuously applying force. Are you suggesting that the integral of the continuous force application (through crank length distance0 in cycling ends up in less work per second than the integral of discrete "impulse" applications in running per second

Not sure what is expected but I got a Stryd last year and was using it for a while. I found my running FTP was about 5-10% higher than my cycling FTP. I didn't do many hardcore tests and they're all stored as cycling activities in my Garmin so difficult to pull up exact numbers.

In a word, yes.

The magnitude of the difference will vary between individuals, depending upon 1) how good of a physiological "motor" you are in the two sports, and 2) your mechanical efficiency when running vs. cycling (with the former varying more between individuals than the latter).

Just as another point of reference, I'm at least as good of a motor when cycling vs. running, and my cycling efficiency is on the high side, whereas my running efficiency is presumably poor (I know that my economy and effectiveness are). Yet, I can still sustain a ~20% higher power output while running.