Power Meters

There are myriad advantages to training with a power meter , as opposed to simply training with a heart rate monitor . By quantifying the amount of force the athlete in question produces, as opposed to relying on the resultant increase in heart rate, the read-outs provided are up-to-the-second accurate and more pertinent to workout goals. 

Different Types of Power Meters

Power meters come in a variety of types, and are mainly differentiated by their varying placement on different parts of the bicycle. It's important to note that many of these implemented gauges require special modifications or unique bike parts in order for them to function.

• Crankset: The crankset meter  is positioned within the crankset of a bicycle, and it measures torque using strain gauges . Using this type of power meter requires a specific crankset, but due its positioning directly on the generation of power, the readings are among the most accurate. 
• Bottom Bracket: Meters based on the bottom bracket  shaft utilize sensors that detect the torque applied to the left pedal and then double this figure to derive the power. Bottom bracket systems are unique to each bicycle, so compatibility is low and the switching of units is often difficult. 
• Freehub: A freehub power meter  is similar to a crankset meter, as it uses strain gauges to measure torque, but is located lower down the drive chain, on the rear hub. Due to its placement, the freehubs readings will be less than their crankset brethren. The upside is that their compatibility is high and their replacement is simple.
• Opposing Force: The opposing force system is a complex system of sensors with the benefit of being able to measure gravity, wind speed, acceleration and frictional drag.
• Applied Force: The applied force method of measurement senses the force in the pedaler's foot directly, and by using the magnitude and direction of the force, figures out the aggregate power. An advantage of this system is that, since both feet are being monitored, one is able to derive the force being generated by each leg individually. Outside of a laboratory setting, however, this system of measurement is unavailable. 

Quick Picks

Power Meters
Power Tap  The CycleOps PowerTap  is a contraption built into the bike wheel, used to measure torque. It weighs 402 grams, and is engineered with wireless transmission technology.	SRM   The SRM Training System  is an 8-sensor crankset power meter weighing in at a little over 600 grams. It guarantees an accuracy of +/2%, and boasts wireless data transmission capabilities.	Ergomo  The Ergomo Pro Power Meter  is a bottom bracket power meter developed to measure the torsion of the axle and converting it into a measurement in watts. One unique advantage of the Ergomo power meter is its non-contact sensors, which provide a highly accurate reading.	Polar  The Polar Power Meter  system vows to revolutionize the way you train by measuring your power output data alongside your heart rate information for thorough and useful readouts.

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