What struck me the most that year was Armstrong’s pedalling style, his high cadence technique. Not that he was the first to ever ride like that—good pédalage (smooth, high cadence style) has always been a mark of a classy rider—but he was the first, in modern era at least, to ride at that kind of high cadence, especially on the climbs.
Cycling commentators and journalists picked up on it too and it became part of the smoke and mirrors campaign that helped create the Armstrong’s myth. Soon, the cycling world—pro, amateur, and everyone in between—was spinning the pedals at 120 rpm.
Is high cadence a fad or does the technique have merit?
The Physics of Cycling Cadence in Plain English
If you ever tried to find an answer to this question and googled it, you probably found what everyone else finds: pages of mumble jumble infused with scientific language no one without a Ph.D. in physiology can understand.
Although human physiology is a complex science with a lot of unknown unknowns—you know, the things we don’t know we don’t know—you don’t need a Ph.D. to understand why high cadence pedalling could be good for you.
Let’s start with physics, a subject I regularly failed at school but managed to catch up on in recent times through reading cycling literature.
Riding a bike requires power, a measure expressed in Watts. We generate power by applying force to the pedals one revolution at a time.
This concept can be expressed as a simple equation:
Power = Force x Cadence
Looking at it in this form, it’s easy to see how power can be increased: either by applying more force (pushing harder on the pedals), or by increasing cadence, or both.
I hope this is clear. Keeping the above formula in mind, let’s compare 2 cadences: 50 rpm vs 100 rpm.
If power stays the same, let’s say 300 watts, the force required to sustain that power at 100 rpm will be 50% less than at 50 rpm. This too is clear enough.
Put another way, if I want to generate and sustain 300 watts, I’ll need to apply less force per pedal revolution at 100 rpm cadence than I’ll need at 50 rpm.
Several interesting consequences follow from this observation.
Physiology of Cycling Cadence in Plain English
The recruitment of the so called “slow” and “fast” twitch muscle fibers varies depending on the force we want to apply to the pedals. The higher the force, the more “fast” twitch fibers will be recruited (track sprinters are “fast” twitch junkies).
The trick with “fast” twitch muscle fibers is they consume more glycogen (fuel) and fatigue quicker. Want more force? You have to pay for it.
This is why you need to be careful with accelerations when racing or why grinding big gears on the climbs will toast your legs (this doesn’t apply to Jan Ullrich).
Lowering the force you apply to the pedals by increasing your cadence creates another useful effect when more “slow” twitch muscle fibers are recruited: more fat is used for fuel. Unlike “fast” twitch fibers that rely on limited supply of glycogen to generate energy, “slow” twitch fibers burn mostly fat, a type of fuel you’ll never run out of. Not only that, but the fat burning energy production uses less oxygen than glycogen burning does.
You win again by using higher cadence.
Force exertion in your body is achieved by muscle contraction. Every contraction—think pedal revolution—reduces blood flow and therefore oxygen delivery to the muscle fibers because of the increased pressure in the contracted muscle. The higher the cadence you ride at, the shorter the contractions are and, therefore, the time periods when the fibers’ oxygen supply is reduced are shorter.
Higher cadence, in other words, allows your muscles to “breath” better.
Finally, one last point. We all know we have a pump inside us—the heart. But not many of us know about our second pump—the so called “peripheral pump”—a system of veins in the legs responsible for returning blood from the lower parts of our body back to the heart.
We need this second pump to overcome gravity to transport blood upward. The peripheral pump works by contracting leg muscles and using vein valves to push blood upstairs.
This pump works best when muscle contractions are short, the type of contractions used with higher cadence. It explains why you can’t stand still for too long on your feet: the peripheral pump stalls because too many muscle fibers are contracted for too long and you begin to feel pain, a signal your body sends you to do something about it before any serious damage is done.
The same principle is at work when we rest our legs against a wall to recover after a race or a hard ride. This time, we use gravity the other way around to help blood to flow more freely back to the heart without using the peripheral pump too much. It spares our muscle fibers from extra work when we want them to recover and rebuild themselves.
What should you do with all this information?
I know what you shouldn’t do, and that is, jump on your bike tomorrow and start spinning at 120 rpm. Instead, think, experiment, and evaluate. Find out if what I wrote here works for you or not.
This is how.
Work Your Fast Twitch Muscles
Make your “fast” twitch muscle fibers work more by using bigger than usual gears on your rides. Don’t be shy, shift your gears to the right by a good chunk, 3 gears at least.
For example, if 53×19 feels like the right gear to use, use 53×16 or 53×15.
Ride overgeared for 20-25 minutes at a time, then have a break for 5 minutes or so and back into bigger gears again. You want medium intensity with this kind of work. Don’t hurt yourself.
After 2-3 “big gear” rides, have a “normal” ride, and then repeat for a total of 6-8 “big gear” rides, including at least one long ride.
As you do this, observe and take notice of how your body deals with this workload.
Do you get fatigued quicker than usual? Any muscle ache? Does it improve as you go along? Does it get worse after each ride?
Work Your Slow Twitch Muscles
After you finish with the big gears, give yourself a week to rest and ride any way you want. Once rested, experiment with high cadence in the same way you did with big gears.
This time, you don’t need to undergear yourself by 3-4 gears, 1 or 2 will do. Using the 53×19 example again, if that’s the gear you feel like using at any given moment, go for 39×16 instead.
Speaking of gears. If you’re not fluent with gear ratios, here’s a useful tip for you:
On a road bike, a difference of 3 teeth at the front equals roughly 1 tooth at the rear.
Example: a 53×19 ratio is about the same as 50×18, or 47×17, or 41×15, and so on. So 39×16 I mentioned above is roughly 54×21, a lower gear than 53×19.
With high cadence, you don’t need to break your rides up into chunks of efforts. Try to maintain higher than “normal” cadence for the entire ride. Aim for 7-10% increase in your cadence. If your “normal”cadence is around 90 rpm, aim for 100 rpm.
Keep in mind that you’re not trying to increase your cadence for the sake of increasing cadence. You’re experimenting. You’re trying to find out if changing cadence one way or another affects your body, and if it does, in what way.
Give yourself at least a week of high cadence training. Observe and evaluate. Do you feel fresher than usual at the end of a ride, especially a long one? Do you feel your body recovers better? Do you need more food or water on these rides? Do you feel like you want to attack a hill sometimes because you feel too fresh?
Write your thoughts and questions somewhere and at the end of the experiment you’ll have some information to think through and evaluate. Armed with this knowledge, you’ll know if you need to work on your cadence or not.
Get on your bike and start experimenting.