Ultrasound imaging as a feedback tool in the rehabilitation of trunk muscle dysfunction for people with low back pain.

This commentary provides an overview of the current concepts and the emerging evidence related to rehabilitative ultrasound imaging (RUSI) for biofeedback purposes. Specifically, the role of RUSI to assess improvements in trunk muscle performance and motor learning will be discussed, highlighting the importance of retention and transfer testing to assess motor learning. The use of RUSI as an extrinsic (augmented) feedback tool and its ability to provide both knowledge of performance and knowledge of results information will be defined. An analysis of the limited available literature related to the role of RUSI as an augmented feedback tool to enhance motor skill acquisition related to the deep trunk muscles will be provided. Future research directions and priorities are recommended.