The Pursuit of POWER
By Dr. Kevin Steele, Ph.D.
Power means many things to many people, but what is power and why has it become important to cycling? A power meter is one of many tools used to impact performance, fitness and other desired physiological outcomes such as weight loss. Power meters used in road cycling have been around since the late '80s, but in the early days, power meters were only available to elite athletes and in sport science laboratories. Today, power meter technology is available in road racing, on indoor bikes and is being used by a wide variety of people. Regardless of one’s age, gender, fitness level or athletic ability, measuring work effort is key to achieving fitness and/or performance goals.
To assure effectiveness and efficiency while training for performance or exercising for a healthy life, both should be based upon fundamental scientific principles. The foundation of these principles is the work to rest ratio; the success of your program is predicated upon how you utilize power and other principles to quantify your work. Having specific information available provides you with the knowledge necessary to objectively design your program to achieve current goals.
Power is defined as “how much work you do and how fast you do it." The “watt” is a measurement of power determined by calculating the rate at which the work is completed, and equals joules per second. “Watt” is commonly used in cycling to express how hard the cyclist is working at that moment, i.e. “pushing 360 watts." Stated in another way, if you squat down and then stand up, the quicker you stand then the more power you will generate. On a bicycle, you can increase your power by adding more resistance and maintaining cadence, or maintain resistance and increase your cadence, the outcome is the same.
When measuring power on a bike, the methodology used is critical to the accuracy of the data being generated. There are many types of gauges and devices that claim to capture power; strain gauge technology has consistently demonstrated the highest levels of validity and repeat-ability in the lab and on the road. A strain gauge is a device that measures the strain of an object by assessing the physical effect of the resistance in proportion to any change in movement. Ideally, the strain gauge is placed on the bike where the most force will be applied by the rider such as the flywheel, the crank arms or the pedals.
One of the main benefits of using power in your training is that there are no external variables that can influence the outcome of your ride. Other devices such as heart rate monitors will “monitor responses” of how your body is reacting to the ride and their data can be affected by variables such as caffeine, stress, lack of sleep, and more, whereas power meters “measure actual work being done." The ideal approach is to use a power meter and a heart rate monitor combined with a good pre-ride preparation strategy.
As mentioned above, the primary reasons for incorporating power into training and exercise is to enhance performance, general fitness or weight loss. Increasing one’s speed, improving ability to climb and improving endurance are all benefits of adding a power component to one’s performance training. Increased strength and endurance are general fitness benefits gained by having power on a Spinner® bike, and a weight loss program can be specifically designed to incorporate a power meter to provide objective protocols that accelerate success.