Background: Weakness of gluteus medius (Gmed) is related with musculoskeletal disorders. Individuals who experience weakness in the Gmed may activate the tensor fasciae latae (TFL) as a compensatory mechanism. Application of isometric hip extension (IHE) with Thera-band may affect the activities of the Gmed, gluteus maximus (Gmax), and TFL, and the activity ratio of Gmed/TFL during side-lying hip abduction (SHA). Objects: To determine the influences of IHE during SHA on Gmed, Gmax, and TFL activities in participants with Gmed weakness. Methods: Three types of SHA exercises were performed: 1) traditional SHA in the frontal plane (SHA-T), 2) SHA with IHE applying Thera-band in the frontal plane (SHA-IHE), 3) and SHA with isometric hip flexion (IHF) applying Thera-band in the frontal plane (SHA-IHF). Results: SHA-IHE significantly showed higher Gmed and Gmax activities than SHA-T and SHA-IHF. SHA-IHF significantly showed higher activity of TFL than SHA-T or SHA-IHE. The activity ratio of Gmed/TFL was significantly higher in the SHA-IHE, SHA-T, and SHA-IHF, in that order. Conclusion: The SHA-IHE resulted in higher activities of Gmed, Gmax and a higher muscle ratio of Gmed/TFL.

INTRODUCTION
MATERIALS AND METHODS
    1. Design
    2. Participants
    3. Instrumentation
    4. Procedures
    5. EMG Data Collection
    6. Statistical Analysis
RESULTS
DISCUSSION
CONCLUSIONS
FUNDING
ACKNOWLEDGEMENTS
CONFLICTS OF INTEREST
AUTHOR CONTRIBUTION
ORCID
REFERENCES

• Sae-hwa Kim(Applied Kinesiology and Ergonomic Technology Laboratory, Department of Physical Therapy, The Graduate School, Yonsei University, Wonju, The Catholic University of Korea Eunpyeong St. Mary's Hospital)
• Hyun-ji Lee(Applied Kinesiology and Ergonomic Technology Laboratory, Department of Physical Therapy, The Graduate School, Yonsei University, Wonju, Samsung Medical Center, Seoul, Korea)
• Seok-hyun Kim(Applied Kinesiology and Ergonomic Technology Laboratory, Department of Physical Therapy, The Graduate School, Yonsei University, Wonju)
• Seung-min Baik(Applied Kinesiology and Ergonomic Technology Laboratory, Department of Physical Therapy, The Graduate School, Yonsei University, Wonju)
• Heon-seock Cynn(Applied Kinesiology and Ergonomic Technology Laboratory, Department of Physical Therapy, The Graduate School, Yonsei University, Wonju) Corresponding author