Differential air pressure systems and methods of using and calibrating such systems for mobility impaired users

A differential pressure system for improving mobility of a disabled individual, comprising:

• a pressure chamber with a seal interface configured to receive a portion of a disabled user's body and to form a seal between the user's body and the chamber, the chamber configured to apply pressure to the portion of the user's body while the user's body is sealed in the chamber;
• a platform in the pressure chamber, wherein the platform is configured to contact the user's body;
• a first load sensor positioned substantially underneath the user's torso and configured to measure the load applied by the user while the user is in the chamber and to provide an output signal;
• a second load sensor coupled to the differential pressure system at a position that is different from the first load sensor, the second load sensor configured to provide an output signal;
• a processor configured to receive the output signals from the load sensors and to calibrate the system for use by the disabled user by generating a relationship between pressure in the chamber and actual weight of the user while the user is sealed in the chamber, wherein the actual weight of the user is the total weight of the user measured by the first and second load sensors at pressure points, the processor regulating the pressure of the chamber according to said relationship.