Range of normality versus range of motion: A functional measure for the prevention and management of low back injury.

The Range of Motion (ROM) is a popular measurement used in the determination of disability for low back pain subjects in spite of serious objections to its clinical usefulness. It is proposed to consider a different index called the Range of Normality (RON) which is defined to be the portion of the ROM that an injured subject is able to do quasi-normally. This permits a direct assessment of the return to work parameters and the restrictions that ought to be placed on activities. It also allows follow up since the RON is expected to fill up the ROM as the injured subject recovers from his injury.