Gizmodo has a fantastic video demonstration of one of the latest hi-tech workout gadgets to grace an Equinox gym. The AlterG Antigravity Treadmill is a NASA-developed device originally meant to train astronauts to walk on the moon. Like many NASA technologies, this one has started to grace high-end gyms around the country and the Equinox at 63rd and Lexington is home to one of these advanced treadmills.

The machine works by pressurizing the runner’s legs inside a bubble held up by neoprene pants worn by the runner. According to the video above, the runner experiences the same respiratory and cardiovascular exercise that would normally occur without the Earth-weight of the runner. Good for the knees, good for the heart!