Work Out Efficiently

When I erg I measure my speed in watts, which essentially tells me how many watts of energy I am generating while I am working out. I decided to try and figure out a way to harness this energy in the hope that I could use it to power a radio that would be used in every high school or college team’s erg room. I started doing some research by looking at electrical bikes and how gyms across the globe have started to use gym equipment as an energy source.

If you walk into a gym you will see rows and rows of machines. There are treadmills, ellipticals, stair climbers, stationary bikes, and various other pieces of electrical equipment. The saddest part of all of this is that not only is all of this equipment plugged in, they come with TV’s. Your typical treadmill uses around 600-700 watts, and by adding a television to that isn’t helping the gym’s carbon footprint. By walking at a steady pace on a treadmill for two and a half hours a week, which is the government’s recommended amount of exercise for the average adult, one generates 110 pounds of carbon dioxide minimum.  I think that it is absolutely ridiculous that our goal in working out is to burn our own bodies’ energy, but we also burn extra insane amounts of energy through using gym equipment. There are such things as manual bikes and treadmills that do not plug in, but on a list of the top ten treadmills, only two are manual. That isn’t making much of an impact. Gyms began to realize that this was not efficient or cost productive, and so many have begun to put their equipment to good use.

The idea of a spin class is really unappealing to a lot of people but there actually is a lot of effort put into it, and so a lot of energy being generated. The Cadbury House in Great Britain has started to place this little black box at the base of each spin bike to collect the energy from all the sweaty people burning all their valuable energy, and putting that energy back into the grid. The Cadbury House in Congresbury, near Bristol will each feed around 100w per hour back into the building’s power supply. Their new treadmills also use around 30% less energy, even with TVs mounted in front of them. More locally, there is a gym in New York City and one in Oregon that has hooked up all their stationary bikes to generator boxes that feed the energy generated by the spinners back into the grid.


I saw the work that was being done to use all the energy generated and decided to try and do some more research to try and figure out how to build my own little machine to capture the energy generated by my ergometer. On a rowing blog I found people who had built bicycle generators and instead of putting them onto stationary bikes put them onto their ergs. I proceeded to look up how to build a bicycle generator and found that It was relatively simple to do so, but not very efficient to power anything greater than a light bulb because there wasn’t a way to store the energy. I then found another source that allowed me to hook up something like a car battery to the contraption so that I could store my energy.

What good would building a generator actually do for our school? Well, assuming whenever we do an erg workout we are going as hard as possible, there is definitely a way we could power a radio for the erg or weight room, and maybe even the entire room’s lighting. It takes around 50 watts to power a radio, and just a little bit more than that to power a generic light bulb, so keep that in mind.  Also keep in mind that an ergometer is only 45% efficient which isn’t that great. A rowers pace obviously varies depending on the duration of the workout, but say my team was doing two 20 minute workouts. We would generate a total of around 4500-5500 watts per person, this is already 45% of the total watts produced, assuming we were going our hardest the entire time. Even if we weren’t going our hardest the entire time, that’s still a lot of watts. If we could power our radios with our sweat then that would be entirely amazing, and not as expensive as one might think.

One thought on “Work Out Efficiently

  1. Hi Claire,

    I really like how you connected the energy subject that we have been focusing in class to what you do in your daily routine. I have never thought about the energy that is produced while you are working out, and I think it is a great idea to try to conserve it. I like how you also did some research yourself to see how much energy your crew team could generate just in one practice. I think you should try to talk to someone about implementing a system where the energy your team generates doesn’t get wasted. While reading this blog, my own ideas started popping up in my head of ways to use the energy produced while you yourself are sweating away your energy. One thing I think a good idea would be to power TVs on treadmills with the energy produced while you are running. Really interesting post!

    – Kristin


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