Generating Electricity in Gyms

Picture a gym filled with people moving in all different ways: treadmills, stationary bikes, rowing ergs, strength machines, and maybe an aerobics class. Now imagine that all of that movement was helping to power the building.

I have seen very small-scale applications. At one point, a job I used to work had a bike that could power a blender, staff and public would hop on and help make some tasty drinks. It was definitely more novelty than anything. But, with improvements in energy storage, could a gym be set up so that it powered itself? This is what Moska and Lebkowski (2025) asked.

First things first, how much energy can a human generate? According to the research covered by Moska and Lebkowski, humans generate between 50-300 W. Of course, this varies based on age, gender, and training level, with professional athletes reaching up to 400 W. Length of time and level of effort would also play a significant role. The authors worked out that a 30-minute session of moderate effort would generate about 63 Wh of energy.

Now, let’s look at the equipment. Stationary bikes, both upright and recumbent, already exist to convert movement into electrical energy, powering built-in displays and control panels as well as external devices connected to the bike. The energy can also be stored in batteries. Rowing ergs would be similar to the bikes in terms of how they work, but the power generated would likely be higher than that of the stationary bikes.

A treadmill would need to be a self-powered or non-motorized system where the movement of the person drives the treadmill belt. Similar to bikes, they can power things directly or it can be stored in batteries. These also already exist. Unfortunately, ones that are powered by an electric motor typically consume between 500 and 2000 W, meaning that the human would not be able to generate enough energy to even power the treadmill.

An interesting option is kinetic floors, where the movement of the floor as people walk or move over it can produce electricity. While they produce a very small amount of energy per step, they benefit from the sheer number of people who move over top of them. Rather than in the group classrooms, an option might be to place these floors in high-traffic areas like entranceways.

The last option is specialized strength machines. Similar to the floors, the amount of electricity generated will be quite low, but there could be a volume effect if the right pieces of equipment were chosen based on popularity or level of use.

What does this all add up to? The energy generation benefits would be small; however, small doesn’t mean pointless. The authors lay out plans for how the equipment could be modified to also provide helpful health analysis to expand the benefits beyond just electricity generation. The use of energy storage is also key to supporting ongoing use. Privately, the payoff for something like this would be 29-45 years, but they do highlight that commercial environments might be able to achieve a return on investment in just one year, which is incredible.

What do you think, would a gym that you helped power appeal to you?