Mechanical properties of the trapezius during scapular elevation in people with chronic whiplash associated disorders--A case-control ultrasound speckle tracking analysis.
BACKGROUND
Approximately 50% of people with Whiplash Associated Disorders (WAD) report longstanding symptoms. The upper trapezius is commonly painful yet its mechanical properties are not fully understood.


OBJECTIVE
This study examined the deformation of different depths of the upper trapezius muscle during a scapular elevation task (shoulder shrugging) before and following loaded arm abduction.


METHODS
A cross-sectional case-control study of 36 people (26 female and 10 male, mean age 38 (SD 11)) with chronic WAD and 36 controls, matched for age and gender. Real-time ultrasound recordings of upper trapezius were taken during both scapular elevation tasks. Post-process speckle tracking analysis was undertaken of three different sections of the upper trapezius muscle (superficial, middle, deep).


RESULTS
The WAD group had lower deformation of the superficial section of the upper trapezius compared to the control group in both concentric and eccentric phases of scapular elevation (p < 0.05) especially before the loaded arm abduction. After arm abduction, the deformation of the trapezius was reduced in both groups but only significantly in the WAD-group (p = 0.03). Within-group analysis revealed that the control group least engaged the deep section of upper trapezius during the task (p < 0.01).


CONCLUSIONS
This study, measuring mechanical deformation of the upper trapezius during a scapular elevation task indicates that persons with WAD may display different patterns in engagement of the muscle sections than those in the control group. Further research is needed to replicate and understand the reasons for and implications of this possible change in motor strategy within upper trapezius. Clinical Trials.gov, Number: NCT01547624.
Department of Medical and Health Sciences, Division of Physiotherapy, Linköping University, 58183 Linköping, Sweden; Rehab Väst, County Council of Östergötland, Lasarettet, 591 85 Motala, Sweden. Electronic address: maria.landen.ludvigsson@liu.se.
Maria
M
Landén Ludvigsson
Department of Medical and Health Sciences, Division of Physiotherapy, Linköping University, 58183 Linköping, Sweden; Centre for Clinical Research Sörmland, Uppsala University and County Council of Sörmland, Katrineholm, Sweden. Electronic address: Gunnel.Peterson@liu.se.
Gunnel
G
Peterson
Centre of Clinical Research Excellence in Spinal Pain, Injury and Health, The University of Queensland, Brisbane, Queensland, 4072, Australia. Electronic address: g.jull@uq.edu.au.
Gwendolen
G
Jull
Computational Life Science Cluster, Umeå University, Umeå, Sweden; Department of Chemistry, Umeå University, Umeå, Sweden. Electronic address: Johan.Trygg@umu.se.
Johan
J
Trygg
Department of Medical and Health Sciences, Division of Physiotherapy, Linköping University, 58183 Linköping, Sweden. Electronic address: Anneli.Peolsson@liu.se.
Anneli
A
Peolsson
D000293:Adolescent; D000328:Adult; D001696:Biomechanical Phenomena / Q000502:physiology*; D016022:Case-Control Studies; D002908:Chronic Disease; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D012540:Scapula / Q000000981:diagnostic imaging / Q000502:physiology* / Q000503:physiopathology*; D064171:Superficial Back Muscles / Q000000981:diagnostic imaging / Q000502:physiology* / Q000503:physiopathology*; D014463:Ultrasonography; D014911:Whiplash Injuries / Q000503:physiopathology*; D055815:Young Adult
Chronic; Trapezius; Ultrasound; Whiplash