title: Relationship between spinal range of motion and trunk muscle activity during trunk rotation.
abstract: [Purpose] The aim of this study was to clarify the relationship between spinal range of motion and trunk muscle activity during trunk rotation using a three-dimensional motion analysis system and surface electromyography. [Subjects and Methods] The subjects comprised 11 healthy men. A three-dimensional motion analysis system measured the trunk rotational angle of 4 segments of the thoracic vertebrae and 2 segments of the lumbar vertebrae. Surface electromyography measured the activities of the unilateral latissimus dorsi, lumbar multifidus, rectus abdominis, external oblique, internal oblique, and transversus abdominis muscles. [Results] During ipsilateral rotation at thoracic vertebral levels, the muscle activity of the latissimus dorsi and external oblique was significantly increased compared with the activity in the 0-10% range of trunk rotation. During early ipsilateral rotation at lumbar vertebral levels, the muscle activity of the internal oblique and transversus abdominis was significantly increased compared with that in the 0-10% range of trunk rotation. During contralateral rotation at both thoracic and lumbar vertebral levels, the muscle activity of the external oblique was significantly increased compared with that in the 0-10% range of trunk rotation. [Conclusion] This study indicates that it is important to consider vertebral segments and spinal range of motion during trunk rotation.
authors.affiliation: Graduate School of Health Sciences, Gunma University, Japan; Department of Rehabilitation, Gunma University Hospital, Japan.
authors.forename: Tomoaki
authors.initials: T
authors.lastname: Sugaya
authors.affiliation: Graduate School of Health Sciences, Gunma University, Japan.
authors.forename: Masaaki
authors.initials: M
authors.lastname: Sakamoto
authors.affiliation: Graduate School of Health Sciences, Gunma University, Japan.
authors.forename: Rie
authors.initials: R
authors.lastname: Nakazawa
authors.affiliation: Department of Rehabilitation Medicine, Gunma University Graduate School of Medicine, Japan.
authors.forename: Naoki
authors.initials: N
authors.lastname: Wada
keywords: Surface electromyography; Three-dimensional motion analysis; Trunk rotation