Whatt is a watt?
Power as a measure of workout intensity
Power is a commonly used measure for the intensity of a workout. To fully understand power, we need to understand work. Anytime you exert a force (either a push or a pull) over a distance, you have performed work. The amount of work you do over a given length of time is your power. For example, on the Arc Trainer, you apply a force to the foot plate and it travels a certain distance over a length of time. The length of time varies based on your speed, measured in strides per minute. In order to increase power, you must either increase resistance or speed…or ideally, both! When we think of powerful movements, like sprinting and jumping, they are always associated with generating a lot of force in a short period of time.
Watts are the unit of measurement we use to measure power. If you want an idea of your workout intensity at any time, check out the wattage - you can find it on the Arc Trainer, a bike, or the rower machine. Sometimes in the U.S., ‘horsepower’ is used in the place of ‘watts,’ but they are both measuring power. The next time you hear about a car with a higher horsepower engine, that means it is more powerful!
Why should I care about watts?
How can this knowledge of power help me get the most out of workouts? Let’s look at the Arc Trainer as an example. If we know how to increase our power, we can increase the intensity of the workout. Increasing the intensity of the workout means increasing calorie burn! Also, working at very high wattage for shorter periods of time can allow us to develop leg strength and power – which is critical for walking, running, and jumping.
Two advanced modes on the Arc Trainer can help us get the most out of our workouts by measuring power. The first mode is called ‘Constant Power’. In this mode, the power on the machine stays fixed. The Arc Trainer does this by changing the resistance as you change your pedaling speed. Remember that power is related to speed and resistance. With that in mind, as you slow down your speed, the machine increases the resistance to keep the power level constant. The opposite is also true- if you speed up, the Arc will decrease the resistance to maintain a constant power output. This mode is great for just steady state cardio – just set the power level and go!
The second advanced mode is called ‘Adaptive Power’ or ‘A2: Power Train.’ This mode functions the opposite way. In this mode, as you speed up, the resistance increases at the same time. When you slow down, the machine drops the resistance automatically, all without you having to change any settings! This mode is perfect for interval training, because the high intensity is truly ‘high’ and the rests are truly ‘low.’ It is in this adaptive power mode where we can see wattage skyrocket, because the best way to increase power is to increase both speed and resistance at the same time!
What do watts mean to me?
‘Watts’ are used to measure power. Working at a higher wattage means higher calorie burn. Increase your power by increasing resistance or speed while on the Arc Trainer, or use one of the advanced power modes to take your training to the next level!
Cory Hofmann, M.S.
Cybex Research Institute