Reliability and Accuracy of a Video Analysis Protocol to Assess Core Ability

ObjectiveTo develop and test a method to measure core ability in healthy athletes with 2-dimensional video analysis software (SiliconCOACH). Specific objectives were to: (1) develop a standardized exercise battery with progressions of increasing difficulty to evaluate areas of core ability in elite athletes; (2) develop an objective and quantitative grading rubric with the use of video analysis software; (3) assess the test-retest reliability of the exercise battery; (4) assess the interrater and intrarater reliability of the video analysis system; and (5) assess the accuracy of the assessment.DesignTest-retest repeatability and accuracy.SettingTesting was conducted in the Stanford Human Performance Laboratory, Stanford University, Stanford, CA.ParticipantsNine female gymnasts currently training with the Stanford Varsity Women's Gymnastics Team participated in testing.MethodsParticipants completed a test battery composed of planks, side planks, and leg bridges of increasing difficulty. Subjects completed two 20-minute testing sessions within a 4- to 10-day period. Two-dimensional sagittal-plane video was captured simultaneously with 3-dimensional motion capture.Main Outcome MeasurementsThe main outcome measures were pelvic displacement and time that elapsed until failure occurred, as measured with SiliconCOACH video analysis software. Test-retest and interrater and intrarater reliability of the video analysis measures was assessed. Accuracy as compared with 3-dimensional motion capture also was assessed.ResultsLevels reached during the side planks and leg bridges had an excellent test-retest correlation (r2 = 0.84, r2 = 0.95). Pelvis displacements measured by examiner 1 and examiner 2 had an excellent correlation (r2 = 0.86, intraclass correlation coefficient = 0.92). Pelvis displacements measured by examiner 1 during independent grading sessions had an excellent correlation (r2 = 0.92). Pelvis displacements from the plank and from a set of combined plank and side plank exercises both had an excellent correlation with 3-dimensional motion capture measures (r2 = 0.92, r2 = 0.90).ConclusionsCore ability test battery with SiliconCOACH grading method is an accurate and reliable way to assess core ability exercise performance.