Background: The lateral step down (LSD) is a form of stair negotiation used by the elderly because it requires less movement of the lower extremity. Although it is necessary to study the amount of pelvic drop and the strength of a hip abductor during LSD for intervention, limited studies have investigated the relationship between the amount of pelvic drop and strength of a hip abductor during LSD in elderly people.
Objects: This study aimed to determine the relationship between the amount of pelvic drop on an unsupported leg and the strength of the hip abductor during LSD in the elderly.
Methods: Thirty elderly people (male: 17, female: 13) were recruited. Subjects performed the LSD task, and the evaluator measured and the amount of pelvic drop on an unsupported side. Also, the isometric strength of the hip abductor was measured in a supine position.
Results: We found significant relationships between the strength of the hip abductor and the amount of pelvic drop (r = –0.386). The average hip abductor strength normalized by body weight was 1.06 N/kg (max: 1.99, min: 0.52) and the average contralateral pelvic drop (CPD) angle was 4.16° (max: 15.3, min: 0).
Conclusion: Our results indicated that the strength of the hip abductor had a moderate correlation with the CPD during a LSD in the elderly. Hip abductor weakness could translate into altered movement of the pelvis.

INTRODUCTION
MATERIALS AND METHODS
    1. Participants
    2. Hip Abductor Strength
    3. Contralateral Pelvic Drop
    4. Procedures
    5. Statistical Analysis
RESULTS
DISCUSSION
CONCLUSIONS
FUNDING
ACKNOWLEDGEMENTS
CONFLICTS OF INTEREST
AUTHOR CONTRIBUTION
ORCID

• Young-kwon Lee(Department of Physical Therapy, The Graduate School, Yonsei University,Kinetic Ergocise Based on Movement Analysis Laboratory)
• Sung-hoon Jung(Department of Physical Therapy, College of Software and Digital Healthcare Convergence, Yonsei University, Kinetic Ergocise Based on Movement Analysis Laboratory)
• Hwa-ik Yoo(Department of Physical Therapy, The Graduate School, Yonsei University,Kinetic Ergocise Based on Movement Analysis Laboratory)
• Oh-yun Kwon(Department of Physical Therapy, College of Software and Digital Healthcare Convergence, Yonsei University, Kinetic Ergocise Based on Movement Analysis Laboratory)