The work required to move a bike down the road is measured in watts. To define it very simply:
Watts = Torque x Cadence, where Torque = Force x Distance; or how hard you press on the pedals multiplied by the number of times per minute you apply this force.
Two cyclists, Bob and Bill, weigh the same, have identical bikes, identical aerodynamics and are riding next to each other at the same speed on a flat road. Because they are riding the same speed and we’ve controlled all the other variables, they are performing the same work, ie, riding at the same watts. However, Bob is mashing at 70rpm while Bill spins at 110 rpms. Bob’s pedaling style dictates that he press hard on the pedals with each stroke. But he does so less frequently than Bill, who is pushing lightly on the pedals but much more frequently.
Low cadence cycling requires us to push harder on the pedals, but what does this mean at the level of our leg muscles? To generate that higher force contraction, your leg muscles must recruit more fast-twitch muscle fibers vs slow-twitch fibers.
CyclingPeaksSoftware.com developed this analogy. I think it’s a good one, but I like to elaborate a bit. Imagine your legs are a book of slow and fast burning matches. The purpose of training is to increase the size, number and flavor (ratio of slow and fast) of your matches, depending on the demands of the race. Sports requiring short bursts of speed favor athletes with lots of fast matches. Endurance events favor slow matches. You can use either match to do the work of racing but the total number of matches in the book is finite. And once you burn a match, it’s gone - you can’t get it back.
Now, back to our discussion of cadence. You are riding on a flat road, approaching a hill that will take you about a minute to climb. You will likely do one of four things:
Option #1: Low cadence = high force = high fast twitch recruitment = burning matches that you may need towards the end of the run. Forget “feels” powerful. Power is watts to the wheel, period. If you can climb a hill at the same speed (equal watts) at 60rpm or 90rpm, choose 90rpm. Conserve your fast twitch fibers so you can recruit them later in the run.
Option #2: See Option #1 and always bring enough gears to the race. In my experience, the only people who attach sexual competency issues to the gearing on their bike are folks who don’t climb. I have (no lie) six cassettes hanging in my garage that I swap on and off my bikes according to the terrain of the ride. I have everything from a 27-12 to a 19-11. You can flatten any hill if you have enough gears on your bike J.
Option #3: Standing = power spike = high fast twitch recruitment = you know the drill. From riding with a powermeter for many years I can tell you that if you don’t have a meter it is VERY difficult to stand in the saddle and not toss out huge watts for a brief amount of time. It might “feel” ok, but chances are very high that you just burned a few matches with your little burst.
Option #4: Bingo! Spin up the hill, burn slow, not fast matches so you can use those matches on the run, burning the last one as you cross the finish line.
What is the optimal cadence?
Ok, so I’ve sold you on the value of high cadence vs low cadence. But what is the optimal cadence? In my experience, most athletes should ride at a cadence of 88-95+ rpm. A few notes here:
Cadence and Training
Some coaches prescribe low cadence intervals as a method to train your body to push harder on the pedals. However, consider the importance of specificity: if you want to run longer, run longer; if you want to swim faster, swim faster; if you want to ride the bike farther, ride the bike farther. If you want to ride the bike faster at 92rpm, then ride the bike fast (high watts, ie greater work output) at 92rpm.
Having said that, both low and high cadence work are useful for increasing your “cadence comfort,” or your comfort within a wide range of cadences. By this I mean you have strong, resilient, well-adapted legs that can handle a broad range of cadences, including that high force/high wattage contraction that may happen if you run out gears, decide to climb out of the saddle, etc. You have a large tool kit to handle a broad range of conditions.
The most common tool is a period of low cadence intervals fitted into the early season. My guidance: