Background: Tensor fasciae latae (TFL) and iliotibial tract (ITB) tightness can pull the pelvis during hip lateral rotation (HLR), increasing pelvic rotation due to muscle tension. Among various tests, the HLR test in the prone position (HLRP) is a clinical evaluation tool for assessing lumbopelvic motion with lower-extremity movement. However, performing the HLRP may result in less compensatory motion and a relatively decreased pelvic rotation angle (PRA) because of a wide base of support. Moreover, there were no studies investigating PRA during an HLR test in the standing position (HLRS). Objects: This study aimed to compare the PRA in the horizontal plane during HLRS and the HLRP between individuals with and without TFL/ITB tightness. Methods: Thirty participants with (n = 15) and without (n = 15) TFL/ITB tightness as assessed by Ober’s test, were recruited. The PRA was measured during active HLRS and HLRP. Two-way mixed analysis of variance was used to identify significant differences in the PRA between groups and within positions. Results: When HLRP and HLRS were performed, the PRA in the horizontal plane occurred at 1.65° ± 0.98° and 7.68° ± 4.69°, respectively, in the TFL/ITB tightness group, and at 1.27° ± 1.07° and 2.37° ± 1.96°, respectively, in the control group. A significant interaction effect was identified between groups and positions on the PRA (p < 0.05). Individuals with TFL/ITB tightness had a significantly greater PRA during HLRS than those in the control group. The PRA during HLRS was significantly greater than that during HLRP in individuals with TFL/ITB tightness. Conclusion: These results suggest that TFL/ITB tightness contributes to increased PRA during HLRS compared with HLRP. Clinically, assessment of the PRA in the standing may provide a functional indicator of compensatory pelvic motion during hip rotation of 45°.

INTRODUCTION
MATERIALS AND METHODS
    1. Participants
    2. Tensor Fasciae Latae/Iliotibial Tract Flexibility
    3. Instruments and Measurement
    4. The Pelvic Rotation Angle During Active Hip LateralRotation Tests
    5. Data Analysis
RESULTS
DISCUSSION
CONCLUSIONS
FUNDING
ACKNOWLEDGEMENTS
CONFLICTS OF INTEREST
AUTHOR CONTRIBUTION
ORCID
REFERENCES

• Ha-yeong Baek(Department of Physical Therapy, The Graduate School, Yonsei University, Department of Physical Therapy, College of Software and Digital Healthcare Convergence, Laboratory of Kinetic Ergocise Based on Movement Analysis, Yonsei University)
• Il-kyu Ahn(Department of Physical Therapy, The Graduate School, Yonsei University, Department of Physical Therapy, College of Software and Digital Healthcare Convergence, Laboratory of Kinetic Ergocise Based on Movement Analysis, Yonsei University)
• Gyeong-tae Gwak(Department of Physical Therapy, College of Software and Digital Healthcare Convergence, Laboratory of Kinetic Ergocise Based on Movement Analysis, Yonsei University)
• Oh-yun Kwon(Department of Physical Therapy, College of Software and Digital Healthcare Convergence, Laboratory of Kinetic Ergocise Based on Movement Analysis, Yonsei University, Department of Physical Therapy, College of Software and Digital Healthcare Convergence, Yonsei University, Wonju, Korea) Corresponding author