SYNOPSIS: 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.

J Orthop Sports Phys Ther. 2007;37(10):627-634. doi:10.2519/jospt.2007.2555

KEY WORDS: motor control, multifidus, therapeutic exercise, transversus abdominis

Rehabilitative ultrasound imaging (RUSI) of the abdominal muscles is increasingly being used in the management of conditions involving musculoskeletal dysfunctions associated with the abdominal muscles, including certain types of low back and pelvic pain. This commentary provides an overview of current concepts and evidence related to RUSI of the abdominal musculature, including issues addressing the potential role of ultrasound imaging in the assessment and training of these muscles. Both quantitative and qualitative aspects associated with clinical and research applications are considered, as are the possible limitations related to the interpretation of measurements made with RUSI. Research to date has utilized a range of methodological approaches, including different transducer placements and imaging techniques. The pros and cons of the various methods are discussed, and guidelines for future investigations are presented. Potential implications and opportunities for clinical use of RUSI to enhance evidence-based practice are outlined, as are suggestions for future research to further clarify the possible role of RUSI in the evaluation and treatment of abdominal muscular morphology and function.

J Orthop Sports Phys Ther. 2007:37(8):450-466; published online 30 May 2007. doi:10.2519/jospt.2007.2558

KEY WORDS: morphometry, obliquus internus abdominis, rectus abdominis, sonography, transversus abdominis

Study Design: Randomized controlled trial. Objectives: To determine if supplementing typical clinical instruction with real-time ultrasound feedback facilitates performance and retention of the abdominal hollowing exercise (AHE). Background: Increasingly clinicians are using real-time ultrasound imaging as a form of feedback when teaching patients trunk stabilization exercises; however, there has been no justification for this practice. Methods and Measures: Forty-eight subjects were divided randomly into 3 groups that received different types of feedback: group 1 received minimal verbal feedback, group 2 received verbal and palpatory feedback, and group 3 received real-time ultrasound, verbal, and palpatory feedback. If the subject performed 3 consecutive correct AHEs during the initial session, she/he returned for a retention test. The performance of 3 consecutive, correct AHEs was the criterion measure; the number of trials to criterion was also recorded during the initial and retention test sessions. Results: The ability to perform the AHE differed among groups (P<.001). During the initial session, 12.5% of subjects in group 1, 50.0% of subjects in group 2, and 87.5% of subjects in group 3 were able to perform 3 consecutive AHEs. Group 3 subjects achieved the criterion in fewer trials than the other 2 groups (P = .0006). No differences among groups were found for the retention testing; however, low power due to fewer subjects precluded a strong interpretation of this finding. Conclusion: Real-time ultrasound feedback can decrease the number of trials needed to consistently perform the AHE; however, the data are inconclusive with regard to retention of this skill.

J Orthop Sports Phys Ther. 2005;35(6):338-345. doi:10.2519/jospt.2005.1757

Key Words: motor learning, transversus abdominis, trunk exercises, trunk stabilization

Muscle fatigue and lack of endurance are complaints of persons with chronic low back pain, but there are no standard ways to assess endurance in this population. The purposes of this study were to examine 3 measures of endurance, to determine relationships of these measures to each other, and to describe effects of gender, obesity, smoking, and self-reported fitness on the clinical measures. The measures of endurance selected were not dependent on maximal voluntary muscular contractions. They were the Sorensen test, median frequency decline of selected muscles, and a submaximal bicycle ergometer test. Thirty-five consenting individuals who were referred for treatment answered questions about their daily exercise prior to being tested. Repeatability of the Sorensen test holding time and of the slope measure of decline in the median frequencies was acceptable for subjects who reported a higher activity level. The decline of the median frequency in the biceps femoris muscles correlated with holding time of the Sorensen test. Smoking, gender, or obesity level did not affect test results on any of the endurance measures. Subjects who reportedly were more active achieved significantly higher scores on the Sorensen test. The importance of controlling for self-perception of activity in physical testing is discussed.

J Orthop Sports Phys Ther. 1994;20(2):81-87.

Key Words: chronic low back pain, muscle fatigue, endurance