A power meter measures, or ‘meters’ the amount of power the rider generates when they turn the pedals – hence the term ‘power meter’. Power meters provide loads of valuable information that cyclists can use to become stronger, faster riders. Power and cadence data is displayed in real-time on a bicycle-mounted computer or watch. In addition, we can save this data for later critique and analysis. However, truth be told, some cyclists don’t truly understand what power really is at a fundamental level. And if we don’t understand the numbers…it makes training to a power meter more difficult. So we wanted to take a quick moment to discuss just what a power meter needs to do to calculate cycling power.
Calculate Cycling Power
In its simplest form, the equation for cycling power is: Power = Torque x Cadence.
Power is a measurement of the work you do on the bike. It is the most accurate way to measure your effort. Cycling power meters measure power in watts. Watts are defined as the energy required to a move a mass a certain distance in a known time period. The mass is you and your bike. The distance is the amount of ground you cover.
Torque refers to how much force the rider is generating. Most power meters use strain gauges to measure torque (these are referred to as direct force power meters). A strain gauge is a tiny electronic device whose electrical resistance varies depending on how much resistance (strain) is put on them. The primary challenge power meter manufacturers must overcome in building an accurate and consistent power meter is accurate torque or force measurement.
Cadence, also called the pedaling rate, is the rate at which the cyclist turns the pedals. It is measured as the number of revolutions of the crank per minute (rpm). For a point of reference, most cyclists turn a cadence of around 80 rpm, however pros often put out a cadence of 90 rpm or higher. Cadence is multiplied by torque in order to determine the power of a single pedal stroke.
So How Do I Produce More Power?
In essence, there are two ways to produce more power on the bike:
- Increase your torque. That is, apply more force to the pedals.
- Increase your cadence. Turn the pedals faster at a given torque.
So know that you know what power is, it’s time to go generate some! Thanks for reading.