Concurrent Validity and Test-Retest Reliability of The Core Stability Test Using Ultrasound Imaging and Electromyography Measurements

Abstract

<h3>Research Objectives</h3> To establish the concurrent validity and test-retest reliability of the formal test. <h3>Design</h3> Two-group test-retest reliability design. <h3>Setting</h3> 1) A certified physical therapist uses a formal test as a pressure biofeedback unit (PBU) to classify the participants into core stability groups and instability groups. 2) Perform a formal test on each group and measure the thickness of abdominal muscles with real-time ultrasound (US). 3) Investigate the correlation between the thickness of abdominal muscles and PBU pressure. 4) Re-measure after 24 hours to verify test-retest reliability. <h3>Participants</h3> 11 young adults with core instability (8 men and 3 women) were able to successfully perform the formal test three consecutive times and completed the abdominal draw-in maneuver core stabilization training augmented by PBU-US-EMG feedback, for 20 minutes a day, 7 days a week, over two weeks.11 young adults with core stability (8 men and 3 women) were unable to successfully perform the formal test three consecutive times. <h3>Interventions</h3> No intervention. <h3>Main Outcome Measures</h3> 1) Real-time US and surface EMG to measure the thickness of deep abdominal and superficial trunk muscle activity. 2) PBU pressure under the abdomen. <h3>Results</h3> The Pearson's correlation analysis showed an excellent correlation between transverse abdominal (TrA) thickness and PBU pressure as well as internal oblique (IO) thickness and PBU pressure, ranging from r=0.856 – 0.980, P < 0.05. The test-retest reliability was good, ICC1,2 = 0.876 for the core stability pressure measure and ICC1,2 = 0.939 to 0.989 for the abdominal muscle thickness measure. <h3>Conclusions</h3> Our findings demonstrate that the formal test, using a PBU and real-time US imaging without confirming the minimal contraction of superficial trunk muscles, as evidenced by EMG, leads to incorrect results. For example, such results in adults or individuals with core instability pathology ultimately influence rehabilitation programs designed to improve core stability. Therefore, the combination of a PBU, real-time US, and surface EMG measurements may help obtain more reliable results from the formal tests and better understand the neuromuscular control mechanisms of core stability. <h3>Author(s) Disclosures</h3> There are no conflicts.