The purpose of this study was to compare the onset times of muscle activities and the order of muscle firing in erector spinae, multifidus, rectus abdominis and biceps brachii during perturbation between subjects with and without work-related chronic low back pain (LBP). Twenty-nine subjects, 14 with and 15 without LBP, participated in this study. The muscle responses were measured by surface EMG (electromyography) during perturbation in eye opened and eye closed conditions. The EMG onset times of the erector spinae, multifidus, rectus abdominis and biceps brachii were similar between groups in eye closed condition. But the onset times of the erector spinae, multifidus, rectus abdominis were significantly delayed in subjects with LBP in eye opened condition. The results provide an evidence for impaired feed-forward control of the trunk muscles in subjects with LBP. Further studies are needed to identify whether the impaired feed-forward control of the trunk muscles is the contributing factor to LBP.

• 노경선(연세대학교 보건환경대학원 인간공학치료학과) | Kyung-sun Roh
• 권오윤(연세대학교 보건과학대학 물리치료학과, 보건환경대학원 인간공학치료학과, 보건과학연구소) | Oh-yun Kwon 통신저자
• 이충휘(연세대학교 보건과학대학 물리치료학과, 보건환경대학원 인간공학치료학과, 보건과학연구소) | Chung-hwi Yi
• 전혜선(연세대학교 보건과학대학 물리치료학과, 보건환경대학원 인간공학치료학과, 보건과학연구소) | Hye-seon Jeon