Say Watt?

There was an article in Outside recently, about ideal power-to-weight ratios: top cycling medico Max Testa had studied Tour de France winners, and found that the ideal power output for winning the Tour is 2.8 watts per pound of body weight; for ordinary weekend athletes Outside gave a figure of 1.6 watts per pound. This is not a "peak output," but is the level you should be able to sustain for about 45 minutes. (For me, that translates to 264 watts at my "ideal weight" of 165 lbs, or 288 watts for my current weight -- and for those following at home, that would mean 462 watts at 165#, or 504 watts at 180#, and I too could win the tour...)

Anyway, the gym I go to has a bunch of stationary bikes with all sorts of calories/watts/etc output. Years ago I used to use these machines a lot more often, and I remember seeing my power output held sustainably at about 250 watts, so I thought I'd see where I now stood on this issue. When I went in on Saturday, I tried to figure my wattage, and almost died -- 250 watts was amazingly hard, I couldn't keep it up for even a minute!

Then I noticed that the power output (also the speed) was constant for any set resistance level, no matter how fast or slow I pedaled. This is where an engineering background comes in handy: I knew that power is resistance times speed, or in this case resistance times pedal RPM, just as speed should be a product of gearing (i.e. resistance level) and pedal RPM. It looks like the bike manufacturer picked some average pedal cadence, figured the bike speed and power output for each resistance level for that cadence, and skimped on the instrumentation. Since wattage and even calories burned, is mostly a gimmick for most people, who wouldn't know or understand if this stuff is accurate, they cheated -- not to put too fine a point on it. This is a fairly prominent sports-equipment company too, one that built their original fortune & reputation on instrumentation fer chrissakes -- no names, but this gives me one more reason not to use their heart rate monitors.

So to make a long story short, on Tuesday I found one of the older bikes, which behaved the way I expected it to (though I can't truly vouch for this one's accuracy either). After warming up I did a bunch of intervals, 1 minute at 300 watts & one minute at 225 watts, fifteen minutes total with cooldown, no problem.

So anyway: I'll probably be taking the singlespeed out tonight; I was thinking of riding Jacobsburg but may just do the towpath. After that, I might go to the ol' WB.