The inability to activate the transverse abdominus (TA) muscle in various positions could potentially be revealed as a risk factor for low back pain. Studies have used a verbal cue for the individual to contract the TA through an abdominal draw-in maneuver during functional positions. That method assumes an understanding and ability for the patient to adequately perform the abdominal draw-in maneuver during weight bearing. The idea of holding an abdominal draw-in maneuver contraction at the same capacity throughout a variety of functional tasks may also be unrealistic for expectations of clinicians and patients, alike.
The functional activation ratio (FAR), measured with ultrasound, can be used to identify individuals that may not be able to contract their TA in various positions. The FAR provides a novel approach to assessing muscle thickness in increasingly functional positions and tasks and teaches patients how to stabilize their spine more effectively.
The use of #ultrasound showing muscle activity during a task in a more functional position than supine on a tabletop or standing quietly allows for further understanding and opens the possibility for more advanced biofeedback and training as a patient progresses > Mangum et al. 2017