Correlation among Functional Leg Length Discrepancy, Muscle Activity, Muscle Contraction Onset Time and Vertical Ground Reaction Force during Simple Lifting Task
10.18857/jkpt.2022.34.4.175
- Author:
Ha Young JIN
1
;
Jin Tae HAN
Author Information
1. Department of Physical Therapy, Graduate School, Kyungsung University, Busan, Republic of Korea
- Publication Type:Original Article
- From:
Journal of Korean Physical Therapy
2022;34(4):175-180
- CountryRepublic of Korea
- Language:English
-
Abstract:
Purpose:Leg length discrepancy causes the posture deformation, gait asymmetry, and lower back pain. The purpose of this study is to investigate the correlation among functional leg length discrepancy (FLLD), muscle activity, muscle contraction onset time and vertical ground reaction force (vGRF) during simple lifting task.
Methods:Thirty-nine subjects participated in this study. FLLD was measured from the umbilicus to medial malleolus of left and right leg using a tape. The subjects performed to lift a 10 kg box from the floor to chest. The muscle activity and muscle contraction onset time of rectus abdominis, erector spinae and rectus femoris was measured using EMG system and vGRF was measured by two force plate. Pearson correlation was used to fine out the correlation among FDDL, muscle activity, muscle contraction onset time and vGRF during simple lifting task.
Results:Correlation between FLLD and difference of muscle activity of short-long side was very high (r > 0.9) during simple lifting task. Correlation between FLLD and difference of muscle contraction onset time of short-long side was very high (r > 0.9) during simple lifting task. And correlation between FLLD and difference of vGRF of short-long side was high (r > 0.7) during simple lifting task.
Conclusion:This study suggests that there is high correlation between FLLD and muscle activity, muscle contraction onset time, and ground reaction force during simple lifting task. Therefore, FLLD could negatively affect the postural balance.
