COSTA MESA, CA — Astronauts on the International Space Station are using technology like that patented by Heart Rate Inc. (VersaClimber), Costa Mesa, CA, for strength training while in space, according to Heart Rate Inc. The astronauts are using a flywheel exercise device that relies on rotary inertia rather than weight stacks.

“This technology does not rely on gravity to pull down weight stacks,” says Brett Collins, vice president of sales and marketing for VersaClimber. “It relies on rotary inertia. It's moving mass on a flywheel, which in turns pulls a rope. It has unlimited resistance in zero gravity.”

With the principle of rotary inertia, resistance is generated by accelerating the rotation of a flywheel during a concentric muscle contraction. Then, resistance is generated while decelerating the flywheel rotation during the eccentric muscle contraction.

Heart Rate Founders Richard and Dan Charnitski approached NASA 13 years ago with the idea for this technology. They suggested that it was a way to maintain fitness and counteract muscle degradation, bone loss and impairment of muscle function while in a weightless environment.

The Charnitskis have since patented the technology and use it in their VersaPulley product. NASA is using its own version of the technology, according to Collins.