The COLBERT, once simply known as T-2, is no ordinary treadmill. Engineers started with a medical treadmill available to anyone on Earth. NASA asked Wyle to nickel plate the parts and make some other modifications, including elastic straps that fit around the shoulders and waist to keep the runner from rocketing across the space station with the first hard step.Heh.
Engineers also faced the serious problem of keeping the treadmill from shaking the whole station with every step taken since the ISS is floating just like the astronauts and wants to react against any movement. Even small actions can shake up delicate microgravity experiments taking place inside the station's laboratories.
While another, older treadmill on the ISS relied on a powered system of gyroscopes and mechanisms to reduce vibrations, the COLBERT's Vibration Isolation System was designed to work without power and be more reliable than its predecessor. The COLBERT rests on springs that are hooked to dampeners. That unit is connected to a standard-sized rack that has been extensively reinforced to handle the power produced by COLBERT users. The rack alone weighs 2,200 pounds.
The one tradeoff? Perhaps fitting for a treadmill named after Stephen Colbert, it is loud.