title: Changes in stiffness of the dorsal scapular muscles before and after computer work: a comparison between individuals with and without neck and shoulder complaints.
abstract: OBJECTIVE
  The aim of this study was to compare the stiffness of the dorsal scapular muscles before and after computer work between individuals with and without neck and shoulder complaints.
  
  
  METHODS
  Thirty subjects were divided into patient (n = 18) and control (n = 12) groups. The stiffness of the upper trapezius, levator scapulae, and rhomboid major was measured using ultrasound elastography before and after a 30-min typing task. The strain ratio of the muscle to an acoustic coupler was calculated (a lower strain ratio value indicates greater muscle stiffness).
  
  
  RESULTS
  At baseline, the strain ratio of the upper trapezius in the patient group (3.762 ± 1.679) (mean ± SD) was significantly lower than that of the control group (7.763 ± 5.921) (p = 0.041). No significant change in the strain ratio of the upper trapezius after the typing task was observed in the patient group (4.158 ± 3.465) (p = 0.549). A significant decrease in the strain ratio of the levator scapulae after the typing task was observed in the patient group (before: 9.006 ± 7.079, after: 5.718 ± 2.847) (p = 0.022), whereas there was no significant change in the control group (p = 0.436).
  
  
  CONCLUSIONS
  The increase in stiffness of the upper trapezius is an objective finding and may be a persistently altered condition in individuals with neck and shoulder complaints. The patterns of change in stiffness of the levator scapulae are different between individuals with and without neck and shoulder complaints.
authors.affiliation: Department of Physical Medicine and Rehabilitation, Tohoku University Graduate School of Medicine, 2-1 Seiryo-cho, Aoba-ku, Sendai, 980-8575, Japan. ishihiro0211@yahoo.co.jp.
authors.forename: Hiroaki
authors.identifier: http://orcid.org/0000-0002-5295-2957
authors.initials: H
authors.lastname: Ishikawa
authors.affiliation: Department of Physical Medicine and Rehabilitation, Tohoku University Graduate School of Medicine, 2-1 Seiryo-cho, Aoba-ku, Sendai, 980-8575, Japan.
authors.forename: Takayuki
authors.initials: T
authors.lastname: Muraki
authors.affiliation: Department of Physical Medicine and Rehabilitation, Tohoku University Graduate School of Medicine, 2-1 Seiryo-cho, Aoba-ku, Sendai, 980-8575, Japan.
authors.forename: Shuhei
authors.initials: S
authors.lastname: Morise
authors.affiliation: Department of Physical Medicine and Rehabilitation, Tohoku University Graduate School of Medicine, 2-1 Seiryo-cho, Aoba-ku, Sendai, 980-8575, Japan.
authors.forename: Yusuke
authors.initials: Y
authors.lastname: Sekiguchi
authors.affiliation: Department of Orthopaedic Surgery, Tohoku University School of Medicine, 2-1 Seiryo-cho, Aoba-ku, Sendai, 980-8575, Japan.
authors.forename: Nobuyuki
authors.initials: N
authors.lastname: Yamamoto
authors.affiliation: Department of Orthopaedic Surgery, Tohoku University School of Medicine, 2-1 Seiryo-cho, Aoba-ku, Sendai, 980-8575, Japan.
authors.forename: Eiji
authors.initials: E
authors.lastname: Itoi
authors.affiliation: Department of Physical Medicine and Rehabilitation, Tohoku University Graduate School of Medicine, 2-1 Seiryo-cho, Aoba-ku, Sendai, 980-8575, Japan.
authors.forename: Shin-Ichi
authors.initials: SI
authors.lastname: Izumi
mesh_terms: D000328:Adult; D016022:Case-Control Studies; D004548:Elasticity; D005260:Female; D006801:Humans; D008297:Male; D019547:Neck Pain / Q000000981:diagnostic imaging* / Q000209:etiology; D009784:Occupational Diseases / Q000000981:diagnostic imaging* / Q000209:etiology; D020069:Shoulder Pain / Q000000981:diagnostic imaging* / Q000209:etiology; D064171:Superficial Back Muscles / Q000000981:diagnostic imaging*; D016526:Workload
keywords: Chronic pain; Elasticity; Levator scapulae muscle; Muscle hardness; Neck and shoulder pain; Rhomboid major muscle; Trapezius muscle; Ultrasound elastography