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Section 3: Principle of Operations
AlterG’s technology was originally conceived as part of an effort to help NASA’s
astronauts maintain fitness during prolonged space flight. AlterG pioneered the concept
of combining this technology with an advanced pressure regulation system and treadmill
into a machine that provides the most effective and comfortable body weight support
system available today.
Physics & Technology Behind the AlterG Treadmill
Differential Air-Pressure Technology
The physical lifting force generated by the AlterG Treadmill comes from a difference in
air pressure around the user’s upper and lower body. The AlterG Treadmill uses this
methodology, known as Differential Air Pressure (DAP) technology to unweight the
user.
An inflatable fabric enclosure covers the treadmill. In the middle of the enclosure is a
hole through which the user steps onto the surface of the treadmill. The user wears a
special pair of shorts, and these shorts are zipped into the hole in the enclosure. A
blower is used to inflate the enclosure. The pressure generated in the inflated
enclosure provides a lifting force against the body. Because the pressure is only slightly
above atmospheric and evenly distributed, the force on the lower body is almost
imperceptible. The AlterG Treadmill provides a level of comfort while exercising
unmatched by other unweighting systems.
Figure 1. Diagrammatic Representation of Lifting Force
