ISO 16840-1:2006

ISO 16840-1:2006 applies to seating intended to provide postural support within a wheelchair. It specifies:
a global coordinate system that permits the determination and recording of a person's posture while seated in a wheelchair;  the standard terms and definitions for use in describing both the posture and the anthropometrics of a person seated in a wheelchair;the terms and definitions for describing the dimensions, location and orientation of seating support surfaces, which together comprise the body support system.
ISO 16840-1:2006 does not specify any methods for use in measuring a person's seated posture, nor does it define terms for dynamic physiological movements (such as flexion or extension).
ISO 16840-1:2006 might be applicable to seating other than that intended to be used within a wheelchair.