A lot of cycling is about power, and generating as much through your legs as you possibly can to reach your finish line in the best possible time. Even when the going gets particularly tough, powering on through can help you to reach the top of the climb more quickly so you can enjoy the descent or level terrain that bit more.
In order to maximise the amount of power you can generate it's important to do plenty of training and many turn to power meters and specially designed power cranksets to help them do that. Power cranks can be fitted to your existing road or mountain bike to deliver accurate, real-time data to a small computer telling you exactly how much power you're generating at that moment and if you're making progress in your training.
If you're taking your cycling training seriously - even if your only other form of training is spinning in the gym - then a power crank and power meter might be the next stage to help you reach your physical goals as well as to smash that PB.