title: Does posture of the cervical spine influence dorsal neck muscle activity when lifting?
abstract: Previous studies have shown that postural orientations of the neck, such as flexed or forward head postures, are associated with heightened activity of the dorsal neck muscles. While these studies describe the impact of variations in neck posture alone, there is scant literature regarding the effect of neck posture on muscle activity when combined with upper limb activities such as lifting. The purpose of this study was to evaluate the effect of three different neck postures on the activity of the different layers of the dorsal neck muscles during a lifting task. Ultrasound measurements of dorsal neck muscle deformation were compared over two time points (rest, during lift) during a lifting task performed in three different neck postural conditions (neutral, flexed and forward head posture) in 21 healthy subjects. Data were analysed by post-process speckle tracking analysis. Results demonstrated significantly greater muscle deformation induced by flexed and forward head postures, compared to the neutral posture, for all dorsal neck muscles at rest (p<0.05). Significant condition by time interactions associated with the lift was observed for four out of the five dorsal muscles (p<0.02). These findings demonstrate that posture of the cervical spine influenced the level of muscle deformation not only at rest, but also when lifting. The findings of the study suggest that neck posture should be considered during the evaluation or design of lifting activities as it may contribute to excessive demands on dorsal neck muscles with potential detrimental consequences.
authors.affiliation: NHMRC CCRE (Spinal Pain, Injury and Health), The University of Queensland, St Lucia, Brisbane, QLD 4072, Australia; Department of Medical and Health Sciences, Division of Physiotherapy, Faculty of Health Sciences, Linköping University, Linköping, Sweden. Electronic address: a.peolsson@uq.edu.au.
authors.forename: Anneli
authors.initials: A
authors.lastname: Peolsson
authors.affiliation: NHMRC CCRE (Spinal Pain, Injury and Health), The University of Queensland, St Lucia, Brisbane, QLD 4072, Australia.
authors.forename: Eivind
authors.initials: E
authors.lastname: Marstein
authors.affiliation: NHMRC CCRE (Spinal Pain, Injury and Health), The University of Queensland, St Lucia, Brisbane, QLD 4072, Australia.
authors.forename: Timothy
authors.initials: T
authors.lastname: McNamara
authors.affiliation: NHMRC CCRE (Spinal Pain, Injury and Health), The University of Queensland, St Lucia, Brisbane, QLD 4072, Australia.
authors.forename: Damien
authors.initials: D
authors.lastname: Nolan
authors.affiliation: NHMRC CCRE (Spinal Pain, Injury and Health), The University of Queensland, St Lucia, Brisbane, QLD 4072, Australia.
authors.forename: Espen
authors.initials: E
authors.lastname: Sjaaberg
authors.affiliation: Computational Life Science Cluster and Department of Chemistry, Umeå University, Umeå, Sweden.
authors.forename: Michael
authors.initials: M
authors.lastname: Peolsson
authors.affiliation: NHMRC CCRE (Spinal Pain, Injury and Health), The University of Queensland, St Lucia, Brisbane, QLD 4072, Australia.
authors.forename: Gwendolen
authors.initials: G
authors.lastname: Jull
authors.affiliation: NHMRC CCRE (Spinal Pain, Injury and Health), The University of Queensland, St Lucia, Brisbane, QLD 4072, Australia; Physiotherapy Department, Royal Brisbane and Women's Hospital, Queensland Health, QLD, Australia.
authors.forename: Shaun
authors.initials: S
authors.lastname: O'Leary
mesh_terms: D000328:Adult; D001696:Biomechanical Phenomena; D002574:Cervical Vertebrae / Q000000981:diagnostic imaging / Q000502:physiology*; D015331:Cohort Studies; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008297:Male; D009119:Muscle Contraction / Q000502:physiology*; D009334:Neck Muscles / Q000000981:diagnostic imaging / Q000502:physiology*; D011187:Posture / Q000502:physiology*; D011446:Prospective Studies; D016059:Range of Motion, Articular / Q000502:physiology*; D012016:Reference Values; D018608:Ultrasonography, Doppler / Q000379:methods; D014891:Weight Lifting / Q000502:physiology*; D055815:Young Adult
keywords: Cervical posture; Lifting; Neck muscle; Ultrasound