Use it or lose it, that mantra of sweaty CrossFit trainers everywhere, goes double in space. Prolonged time in null gravity means that astronauts loose bone mass and muscle tone — which is why astronauts spend two-and-a-half hours per space day exercising. (See Japanese astronaut Koichi Wakata trying out the Combined Operational Load Bearing External Resistance Treadmill — COLBERT — above.) In a novel way to fight space weakness, MIT researchers constructed a stationary cycle in the middle of a centrifuge sized to fit in the International Space Station.

The centrifugal force, the scientists say, could mimic that of Earth’s gravity. (Think Kubrick’s rotating spacecraft.) And the cycle ergometer works just like the wheels of a stationary bike. A preliminary earth-bound study in the journal Acta Astronautica found low reported nausea and high forces on the foot, thought to promote bone growth.

MIT aeronautics professor Laurence Young, who helped design the device, is concerned that once we get to Mars, for instance, years of space travel will have sapped our human envoys of their strength. “You really don’t want to send a jellyfish to represent us on another planet,” he told MIT News.