I believe there is no topic in cycling that is covered so extensively as cadence. One of the reasons for that is that nowadays you really have so much to choose from. The lightest gear until the 1980s was 42 on the front and 19 sprockets on the back. Currently, you can buy a group set with 34 teeth both in the front as well as in the back, which makes your gearing ratio more than twice as easy. So basically, today anyone can take their bike up the most brutal climbs in the Alps. However, sometimes you can question whether it wouldn’t make sense to buy a pair of hiking shoes instead of a bike.
High cadence or not?
But besides having something to choose from, we also see pro cyclists flying uphill with really high cadences. This clearly adds fuel to the fire of the cadence debate, since most recreational cyclists find it nearly impossible to have a cadence above 90 rpm. So, what is going on here? Before we dive into this, there is one major distinction that is often overlooked. We have to make a distinction between an ideal cadence where a lot of factors are put into play and the most efficient cadence where it’s just about the equation of energy costs and mechanical output.
Despite what you might think, the most efficient cadence in terms of energy costs and mechanical output is way lower than expected. Research shows that for both experience and inexperienced riders riding around 60 rpm results in significantly lower oxygen costs than higher cadences. So, this question is actually not that difficult to answer.
Other factors come in play
However, looking at it like this is a bit oversimplified. The problem with a really low cadence for example is that the muscle strain is really high. It means that adopting a low cadence might be a good idea for one short climb. But what if the goal is to conquer multiple climbs, even on multiple days? And looking at cadence from this oxygen efficiency standpoint doesn’t answer the question why pros pedal at really high cadences. They must know what they are doing, right? And this is right, because there are also a lot of other factors in play, like experience, power output, muscle fibre types, gradient and speed.
First of all, the muscle fibre distribution is important. What we know is that a muscle is most efficient in contracting at 1/3 of its maximum contraction speed. This maximum contraction speed is dependent on the muscle fibre type. The body contains fast and slow twitch fibres and depending on the distribution of these types the ideal contraction speed is different. Having more anaerobic fast switch fibres should result in a higher cadence than being a more aerobic endurance kind of cyclist.
Also, the gradient of the road is a factor here. When you pedal uphill there is less kinetic energy involved and your position on the bike is different. This results in a higher peak pedal force and this peak is earlier in the down stroke than on the flat. So, because the pedal force pattern is different, when and which muscle groups do the heavy lifting also changes. As a result, the ideal contraction velocity changes also. It basically means that with a higher speed and more kinetic energy on the flat an ideal cadence should be around 90 to 100 rpm depending on the exact speed, but uphill between 70 and 80 rpm or even lower on steeper climbs.
Thirdly, the power output is an important factor. If you pedal on a low power output, it’s inefficient to have a high cadence because a lot of energy goes on to moving the legs instead of turning the pedals. So, it seems efficient that the lower the power output gets, the lower the cadence should be adopted. In line with this is the factor of the level of the rider. A pro simply delivers higher power numbers, so the percentage of the amount of energy that goes to waste in moving the legs is small compared with low-level riders. Experienced riders also have a better pedal stroke. That means that at higher cadences, the interplay between all the muscles still delivers a smooth pattern without any dead spots. So, less experienced riders deliver less efficient force patterns when the cadence gets higher. Another factor that experienced riders hold above less experienced ones, is the better you get the more blood vessels are present to provide oxygen to all the muscles. This training effect is capillarization. New research shows that at a high cadence blood flow drops in the thighs compared with a lower cadence at the same intensity. It seems logical that having more blood vessels can postpone or diminish this effect.
So, putting all of this into perspective, it seems nearly impossible to answer what an ideal cadence actually is. There are just so many variables and possible outcomes. Luckily for you the body is actually quite capable of letting you know what the most comfortable and therefore the most ideal cadence is. All you have to do is listen to your body and turn off your brain. Just make sure you don’t copy what you see on television unless you are actually a pro. But don’t make the mistake that you shouldn’t train on high and low cadences. Training is actually all about letting the body feel uncomfortable so there is an urge to get better. So, training on different cadences will definitely help in getting you into the pro ranks.