Power meters are increasingly becoming the tools of choice for cyclists looking to improve their fitness. Measuring wattage is currently the most accurate way to tell how fit you are on a bike.
Direct measure power meters come in many different varieties: housed in crank spiders and crank arms, hubs and pedals. They're expensive pieces of equipment, starting at around £600 / $800 and going up from there.
BikeRadar's power meter page brings you all the latest reviews, news and guides on these popular gadgets.