Cadence is the speed you turn your legs to propel a bicycle forward, and is most commonly measured in terms of revolutions per minute (RPM). Out of everything that most cyclists obsess about, cadence is usually well down on the list, and yet it is where a lot of easy gains can be made.
It is worth a recap about power.
Power = Force * Velocity
In a cycling context, force is dependant on strength, and velocity is dependant on cadence.
High cycling Power = big gear*high cadence. It is as simple as that.
To generate more force you need to work at becoming stronger and that takes a lot of physical effort.
To generate more velocity you need to work at improving your cadence and that takes less physical effort (but arguably more mental effort)
What is your ideal cadence?
There has been a lot of research on this topic and a lot of smoke and mirrors. Yes, riding at 50w at 50rpm, as one test was set up, maybe more efficient than riding at 50w at 100rpm, but who wants to ride around at 50w!
My general advice is that for general riding, on flat to undulating ground, you want to aim for a cadence of between 85-100rpm. For climbing I don't like to see cadences lower than around 70rpm for long periods of time. Cycling with a low cadence places more strain on the muscles and back, and will cause fatigue. Spinning at a higher rate reduces muscular stress, and places more emphasis on your cardiovascular system which has more 'capacity' and will recover much more quickly from bouts of hard work.
All but one of the professional hour record breakers in my lifetime won with an average cadence of over 100rpm. That's got to tell you something about how to go fast!
If your current 'cruise around cadence' is lower than 85rpm then you really should make some changes to improve your endurance and speed.
As with any change you need to make gradual changes. Part of speeding up the legs is not physical at all, it is neural. Training the brain to send messages to your legs to move faster is surprisingly hard. If you are currently riding around at 70rpm (I bet some of you are!) then trying to increase to 95rpm in one move will be a disaster. You will find it extremely difficult and you will give up quickly.
Get it Visible
That which we don't measure will not change. If you do not have a cadence sensor, buy one, fit it, and make sure that you have cadence on the front screen of your bike computer.
Chunk it up
Let's say you want to improve from 75rpm to 95rpm, thats a 20rpm increase or more interestingly a 27% increase. This is going to be impossible if you shoot for a binary change. Your heart rate will be sky high, your pedalling technique will be all over the place and you will give up.
Instead chunk the desired improvement up into 5rpm buckets. Aim to increase your average cadence to 80rpm for the first few rides. Even this will feel strange at first and you will be surprised how hard it is to keep it up. Once 80rpm feels like the new normal then aim to increase to 85rpm and so on.....
Get really Fast
To improve neural pathways and 'teach' the legs to move more quickly, I like to prescribe some super fast cadence drills that are best done on an indoor trainer.
Workout: Complete Cadence: Choose an easy gear and wind up to the highest cadence you can achieve without losing control and bouncing (power should be no higher than 60% FTP). Ride for 4.5 minutes at this rate. Then for 30 seconds spin as fast as you can, not worrying about control. Repeat this 5 minute sequence for a total of 20-40 minutes. At the end of the session check your average cadence and make a note of it. Next session try and increase this average and so on. You will improve your average very quickly. Call me when you can average 120rpm for the whole session.
Check your set up
Your cadence is affected by the shape of your body. Remember back in school physics classes when doing experiments involving moving objects with pulleys and levers? Well guess what - longer levers are stronger but move more slowly than short levers. So for cycling, the lever we are most interested in is our thigh bone. Long femurs are generally better for cycling because they can exert more pressure for a given force.
If you have particularly long femurs then you will want a long crank length. Short femurs then a shorter crank will suit your body type. Funny thing is, most bikes these days come with a crank length that will suit the average femur length. So if you have either very long or very short legs then it would be worth checking that you have the most appropriate crank length.
If you are building a new bike from scratch then I would now recommend fitting a shorter crank for most people, say a 170mm or even 165mm even if you are of average to short femur length.
Increasing cadence will improve your endurance by placing less demands on your muscles, which tire quickly. It will also improve your speed for a given muscular effort.
In the table below we can see how a given gear ratio and cadence translates to speed. Firstly let's look at a nice easy climbing ratio of 34/27 - that means you are using the small ring on a compact chain-set, and a large 27 tooth cog on the rear cassette. At 60rpm (which I bet many of you are climbing at) you are moving the bike at 9.58kph. If you drop down a gear to a 30 tooth cog on the rear, and increase your cadence to 70rpm, you increase your speed to 10.02kph. Thats a 4.6% increase in speed. On a 10km climb, the easier gear, higher cadence option works out at 2m 45s faster. If you can master a higher cadence you will be able to climb faster with less muscular strain and hence better endurance.
Now let's look at a fast gear ratio. 50/12 at 90rpm generates a speed of 47.54kph. Drop down a gear to a 50/13 and increase cadence to 100rpm and you are going 48.77kph a 2.6% gain. In a time trial this makes a massive difference and again the higher cadence will spare your legs and enable you to go faster for longer. Improving your cadence by 10rpm is not trivial but it is possible over a relatively short timescale.
Helping our riders improve cadence is a key deliverable from our coaching. It's is one of the first things I look at when analysing a workout file and is the one element of cycling that I keep banging on about like a stuck record! Having seen the dramatic impact it has had on peoples' cycling, and how relatively effortless it is to improve, it is a no brainer in terms of a big marginal gain.
Have a great weekend and remember spinning is winning and grinding is well.....just a grind.