A differential air pressure system has a pressure bag with windows and preferred folding configuration such that when the bag is folded no window is folded. The pressure bag is supported by a lift support that is proximal to a user control panel and adjacent to or nearly adjacent to the user who is coupled to the pressure bag. A treadmill base for use with differential air pressure equipment is provided. There are various improvements provided to adapt the operations of the DAP system via the use of separate pressure volume and non-pressure volume portions of the treadmill base. Various improvements to serviceability and repairs are provided by placement of components outside of the pressure volume portion or by providing one or more pressure volume access points.
