Use of an inclinometer to measure flexibility of the iliotibial band using the Ober test and the modified Ober test: differences in magnitude and reliability of measurements.

STUDY DESIGN

Test-retest design to evaluate the reliability of the measurement of iliotibial (IT) band flexibility using an inclinometer to measure the hip adduction angle.

OBJECTIVES

The primary objective was to determine the intrarater reliability of the Ober test and the modified Ober test for the assessment of IT band flexibility using an inclinometer to measure the hip adduction angle. A secondary objective was to determine if a difference existed between the measurements of IT band flexibility between the Ober and modified Ober test.

BACKGROUND

The Ober test and the modified Ober test are frequently used for the measurement of IT band flexibility. To date, data documenting the objective measurement of flexibility of the IT band is scarce in the literature.

METHODS AND MEASURES

Sixty-one subjects, with a mean age of 24.2 (SD = 4.3) years, were measured during 2 measurement sessions over 2 consecutive days. During each measurement session, subjects were positioned on their left side and, with an inclinometer at the lateral epicondyle of the femur, hip adduction was measured during the Ober test (knee at 90 degrees of flexion) and the modified Ober test (knee extended). If the limb was horizontal, it was considered to be at 0 degrees, if below horizontal (adducted), it was recorded as a positive number, and if above horizontal (abducted), it was recorded as a negative number.

RESULTS

The ICC values calculated for the intrarater reliability of the repeated measurement were 0.90 for the Ober test and 0.91 for the modified Ober test. Results of the dependent t test indicated a significantly greater range of motion of the hip in adduction using the modified Ober test as compared to the Ober test.

DISCUSSION AND CONCLUSION

The use of an inclinometer to measure hip adduction using both the Ober test and the modified Ober test appears to be a reliable method for the measurement of IT band flexibility, and the technique is quite easy to use. However, given that the modified Ober test allows significantly greater hip adduction range of motion than the Ober test, the 2 examination procedures should not be used interchangeably for the measurement of the flexibility of the IT band.