Originally Posted by
Drew Eckhardt
Where power = torque * rpm, torque becomes infinite as rpm approaches zero. Eventually you run out of physical strength, and at some point you're not pushing fast enough to recruit sufficient muscle fibers.
_Training and Racing with a Power Meter_ tells the tale of a racer who was dropped every time he spent over 5 minutes at his FTP but cadence below 70 RPM. Lower gears fixed that problem.
This is what I'm afraid I experienced. At about mile 50 there was a 5 mile climb averaging 5% (obviously some of this climb has short stretches much higher than 5). Then a flat of about 2 mile, then a 3 mile climb averaging over 9% - again with segments well over 9%. I just didn't have enough energy left to spin up the last 3 miles so I had to use a lower cadence. But as I used the lower cadence, my power just kept decreasing. I have very low gears, but at these grades it's tough for my fitness level. To me I've got 2 ways to fix the problem: 1)increase fitness & threshold so I can spin up the climb at mile 60 or 2)improve power sustained power output at lower cadence. I'll probably just work on both.