title: Relaxation phenomenon in lumbar trunk muscles during lateral bending.
abstract: This paper reports myoelectric activity measurements in the lumbar trunk muscles when subjects performed tasks involving various degrees of lateral bending. Biomechanical model analyses were made to estimate the tensions in the lumbar trunk muscles required to perform those tasks. The tensions and the activity measurements were compared to see if a muscle relaxation phenomenon occurred. A relaxation phenomenon in the erector spinae muscles was observed to occur in quiet standing in a laterally-bent position of the trunk, qualitatively similar to the flexion-relaxation phenomenon reported by Schultz et al. in 1985(13). However, no relaxation was observed to occur in the lateral oblique abdominal muscles in laterally-bent postures of the trunk.
authors.affiliation: Department of Mechanical Engineering, The University of Toledo, Toledo, Ohio, USA.
authors.forename: D D
authors.initials: DD
authors.lastname: Raftopoulos
authors.forename: M C
authors.initials: MC
authors.lastname: Rafko
authors.forename: M
authors.initials: M
authors.lastname: Green
authors.forename: A B
authors.initials: AB
authors.lastname: Schultz