Cadence in cycling is the speed at which your legs turn. It is measured in revs per minute / pedal rotations per minute.
Much the easiest way to measure cadence is with an attachment to your bike computer, but it is also easy to calculate as you are cycling along - keeping an eye on the clock of your bike computer, count how many pedal turns you make in 30 seconds (and double it for a one minute result).
The problem with counting your own cadence while cycling along is that the act of counting and looking at the watch can actually change the speed at which you are pedalling. There are also some circumstances where it is less easy to manually count - going up a steep hill for example.
Once you have counted your own cadence a few times you will quickly gain a natural feel for whether you are turning at 60 rpm or 110 rpm.
Casual cyclists will tend to have a cadence around 60 rpm, professional cyclists up to about 110-120 rpm. Your goal is somewhere between the two. Lance Armstrong was well known for maintaining avery high cadence, around 120, even on steep mountains.
Very broadly speaking, it is a good idea to get used to cycling at a reasonably fast cadence - say 90-100. This can seem unnaturally fast at first, but with practice will become second nature. The principle is that it is less stressful on your muscles if you can pedal faster, but with each turn taking less pressure.
You will notice this very quickly when you get used to turning the pedals faster - cycling in a difficult gear at 50 rpm is much more work for your legs than cycling in an easier gear at 80 rpm - assumaing the same overall speed.
Pedalling at a low cadence is known as 'mashing', while a high rotation speed is called 'spinning'.
In technical terms, cycling at a low cadence with great force uses 'fast twitch muscle fibres' while cycling at a high cadence with less force uses 'slow twitch muscle fibres'. Fast twitch muscle fibres use locally stored energy (glycogen in the muscles) that will run out after an extended period of exercise,and tire easily whereas slow twitch uses fat, much more available in the body and much better able to cope with extensive periods of effort.
There are still times when you might use slow pedalling (eg that extra steep part of the hill where you are standing up on the pedals), but in general, almost all aspects of your cycling will be improved, from endurance to overall speed, if you can use a target cadence of 90-100 rpm.
This even applies on hills. You should aim to use an easy gear, and keep pedalling at your preferred cadence, rather than make great efforts in a gear that is a bit too hard and in which you can only manage 55 rpm.
As with all cycling training, the best way to attain a goal is simply to try and do it! One approach is:
- Find out your current cadence
- Set an intermediate goal, say 10 % faster than your current level
- Do regular 'intervals' in which you cycle for a couple of minutes at a time at a rate 15-20 % faster than your current level. You can change to an easier gear to do this of course.
- Pretty soon you will become used to pedalling faster, and your cycling will feel better for it.
Very likely you will then be able to forget about cadence training, with your new level seeming 'normal' - but still remember to monitor and check the rate sometimes, to be sure it isn't gradually falling away again.