Power meters have been around nearly 30 years, since SRM developed the first system in 1986, but they’re more popular – and affordable – now than ever.

However, despite the falling price of power meters – now available hundreds rather than thousands of pounds – buying one is still a considerable investment.

That said, there are many advantages to using a power meter over a heart rate monitor or a riding on ‘feel’ and it’s for good reason that a power meter has become the most popular training tool in the professional peloton.

The main advantage is that using a power meter takes out all the guess work involved in estimating how well you are riding. With a power meter on your bike, there is a quantitative number that tells you exactly how much power you are putting out – or, in other words, how well (or badly) you are going.

A power meter doesn’t replace a heart rate monitor – in fact, they are actually telling you different things. Heart rate is a relative figure which measures your body’s response to effort – or its input – whereas power is an absolute figure which instantly measures your output, regardless of the effort required to reach that number.

In short, a power meter doesn’t lie, whereas heart rate can be affected by a number of external factors, such as fatigue, hydration and temperature. It is also relatively slow to respond to an effort. Using a heart rate monitor and power meter will allow you to see how your body is responding to training.

So how does a power meter work?