Background: Considering the kinetic chain of the lower extremity, a pronated foot position (PFP) can affect malalignment of the lower extremity, such as a dynamic knee valgus (DKV). Although the DKV during several single-leg movement tests has been investigated, no studies have compared the differences in DKV during a single-leg step down (SLSD) between subjects with and without PFP.
Objects: The purpose of this study was to compare the DKV during SLSD between subjects with and without PFP.
Methods: Twelve subjects with PFP (9 men, 3 women) and 15 subjects without PFP (12 men, 3 women) participated in this study. To calculate the DKV, frontal plane projection angle (FPPA), knee-in distance (KID), and hip-out distance (HOD) during SLSD were analyzed by twodimensional video analysis software (Kinovea).
Results: The FPPA was significantly lower in PFP group, compared with control group (166.4° ± 7.5° and 174.5° ± 5.5°, p < 0.05). Also, the KID was significantly greater in PFP group, compared with control group (12.7 ± 3.9 cm and 7.3 ± 2.4 cm, p < 0.05). However, the HOD not significantly differed between two groups (12.7 ± 1.7 cm and 11.4 ± 2.5 cm, p > 0.05).
Conclusion: The PFP is associated with lower FPPA and greater KID. When assess the DKV during SLSD, the PFP should be considered as a crucial factor for occurrence of DKV.

INTRODUCTION
MATERIALS AND METHODS
    1. Subjects
    2. Procedures
    3. Two-dimensional Video Analysis
    4. Statistical Analysis
RESULTS
DISCUSSION
CONCLUSIONS
REFERENCES

• Hyun-sook Kim(Department of Physical Therapy, Yeoju Institute of Technology, Yeoju)
• Hwa-ik Yoo(Department of Physical Therapy, The Graduate School, Yonsei University/Kinetic Ergocise Based on Movement Analysis Laboratory)
• Ui-jae Hwang(Kinetic Ergocise Based on Movement Analysis Laboratory/Department of Physical Therapy, College of Health Science, Yonsei University)
• Oh-yun Kwon(Kinetic Ergocise Based on Movement Analysis Laboratory/Department of Physical Therapy, College of Health Science, Yonsei University) Corresponding Author