Assessment of stretching of the iliotibial tract with Ober and modified ober tests: An ultrasonographic study

Objective: To assess stretching of the iliotibial tract with Ober and modified Ober tests, by assessing morphologic changes of the tract using ultrasonography during stretching. Design: Cross-sectional study. Setting: Orthopedic laboratory. Participants: Thirty-six healthy subjects (age, 24.3 +/- 4.0 y) were recruited. They had no history of previous low back, gluteus, hip, or knee pain and satisfied the inclusion criteria for this study. Intervention: Each subject was randomly assigned to first undergo either the Ober test or the modified Ober test, and 30 minutes after the first to undergo the other test. Measurements were obtained with the subjects lying on the right side. The left knee was flexed 90 degrees for the Ober test and positioned at 0 degrees for the modified test. Main Outcome Measures: The iliotibial tract widths in subjects were measured in 3 gradually increased hip adduction positions (neutral, adducted, adducted with weight) when performing Ober and modified Ober tests. Ten of these 36 subjects were randomly chosen to undergo a repeat of the same protocol to test the reliability of ultrasonographic measurements in the iliotibial tract. Results: Ultrasonography was reliable in measuring the width of iliotibial tract (intraclass correlation coefficient range, .81-82). The width of the iliotibial tract was significantly reduced from the neutral to adducted position of the hip with both Ober (P=.001) and modified Ober (P<.001) tests. However, with further stretching using a greater hip adduction angle, the width of the iliotibial tract was only reduced with the modified Ober test. Conclusions: Both the Ober and modified Ober tests are effective in the initial stage of stretching of the iliotibial tract. However, the modified Ober test might be more effective in stretching the iliotibial tract if a further stretching effect is desired.