Background: Aging is accompanied by progressive changes in neuromusculoskeletal function and sensory motor coordination that can influence balance performance in elderly individuals. The single-leg stance (SLS) is commonly used as a simple and practical tool to evaluate balance and functional lower-extremity control. Although hip abductor (HABD) muscles are regarded as the primary stabilizers of the pelvis during unilateral tasks, the association between HABD strength and trunk and pelvic kinematics during SLS in elderly remains poorly understood. Objects: This study aimed to investigate the relationship between HABD muscle strength and trunk and pelvic kinematics during SLS in community-dwelling elderly females. Methods: Forty-three females aged 65 years or older elderly were participated in the study. The isometric HABD strength was measured using a tension sensor and normalized to body weight. Two-dimensional kinematic data, including hip adduction angle, pelvic drop angle, trunk leaning angle, and pelvic shift horizontal displacement, were analyzed during the initial 5 seconds of SLS using Kinovea software. Linear mixed-effects models adjusted for age, height, body weight, and body mass index were used as the primary analysis to examine associations between HABD strength and kinematic variables. Pearson correlation analyses were additionally performed to assess relationships. Results: Linear mixed-effects model analyses revealed no significant associations between HABD strength and any trunk or pelvic kinematic variables during SLS. In Pearson correlation analyses, with no significant relationships between HABD strength and trunk, pelvic kinematics. Conclusion: HABD strength was not significantly associated with trunk or pelvic kinematics during SLS in elderly females. These findings suggest that postural control during SLS is not determined by HABD strength alone.

INTRODUCTION
MATERIALS AND METHODS
    1. Participants
    2. Procedure
    3. Hip Abductor Strength
    4. Two-Dimensional Kinematic Analysis
    5. Statistical Analysis
RESULTS
DISCUSSION
CONCLUSIONS
FUNDING
ACKNOWLEDGEMENTS
CONFLICTS OF INTEREST
AUTHOR CONTRIBUTIONS
ORCID
REFERENCES

• Il-kyu Ahn(Department of Physical Therapy, The Graduate School, Yonsei University, Kinetic Ergocise Based on Movement Analysis Laboratory, Yonsei University)
• Ha-yeong Baek(Department of Physical Therapy, The Graduate School, Yonsei University, Kinetic Ergocise Based on Movement Analysis Laboratory, Yonsei University)
• Seung-yoon Han(Department of Physical Therapy, The Graduate School, Yonsei University, Kinetic Ergocise Based on Movement Analysis Laboratory, Yonsei University)
• Oh-yun Kwon(Department of Physical Therapy, The Graduate School, Yonsei University, Department of Physical Therapy, College of Software and Digital Healthcare Convergence, Yonsei University, Wonju, Korea) Corresponding author
• Sung-min Ha(Department of Physical Therapy, College of Health Science, Sangji University)