title: Effects of aging on mechanical properties of sternocleidomastoid and trapezius muscles during transition from lying to sitting position-A cross-sectional study.
abstract: OBJECTIVE
  The aim of this study was to analyze the effects of aging on the viscoelastic properties of the upper trapezius (UT) and the sternocleidomastoid (SCM) muscle during transition from lying to sitting position.
  
  
  METHODS
  The study included 39 older (mean age 67±5.9years) and 36 younger (21.1±1.8years) women. Tone, stiffness and elasticity of the UT and the SCM were measured by means of myotonometry (MyotonPRO) in lying and then, in sitting position. The results were compared using two-way analysis of variance.
  
  
  RESULTS
  Irrespective of the position, older women presented with significantly higher muscle tone, stiffness and elasticity than younger subjects (P<0.05). In both groups, the transition from lying to sitting position resulted in a decrease (P<0.05) in the tone and stiffness, but not the elasticity (P>0.05) of the SCM, and stimulated an increase in the tone, stiffness and elasticity of the UT (P<0.05). The degree of changes in both study groups was similar, except from the absolute value of the UT elasticity, significantly higher increase in older women than in younger subjects (P<0.05).
  
  
  CONCLUSIONS
  Age contributes to an increase in the stiffness and tone of the UT and the SCM, as well as to a decrease in the elasticity of these muscles in female subjects. In contrast, age exerts only a slight effect on the mechanical properties of both muscles during transition from lying to sitting position.
authors.affiliation: Department of Musculoskeletal Rehabilitation, Poznan University of Physical Education, Poland. Electronic address: p.kocur1@wp.pl.
authors.forename: Piotr
authors.initials: P
authors.lastname: Kocur
authors.affiliation: Department of Pulmonological and Rheumatological Rehabilitation, Poznan University of Physical Education, Poland. Electronic address: grzeskowiak@awf.poznan.pl.
authors.forename: Marcin
authors.initials: M
authors.lastname: Grzeskowiak
authors.affiliation: Department of Musculoskeletal Rehabilitation, Poznan University of Physical Education, Poland. Electronic address: wiernicka@awf.poznan.pl.
authors.forename: Marzena
authors.initials: M
authors.lastname: Wiernicka
authors.affiliation: Department of Musculoskeletal Rehabilitation, Poznan University of Physical Education, Poland. Electronic address: goliwas@awf.poznan.pl.
authors.forename: Magdalena
authors.initials: M
authors.lastname: Goliwas
authors.affiliation: Department of Musculoskeletal Rehabilitation, Poznan University of Physical Education, Poland. Electronic address: lewandowski@awf.poznan.pl.
authors.forename: Jacek
authors.initials: J
authors.lastname: Lewandowski
authors.affiliation: Department of Musculoskeletal Rehabilitation, Poznan University of Physical Education, Poland. Electronic address: lochynski@awf.poznan.pl.
authors.forename: Dawid
authors.initials: D
authors.lastname: Łochyński
mesh_terms: D000328:Adult; D000368:Aged; D000375:Aging / Q000502:physiology*; D003430:Cross-Sectional Studies; D004548:Elasticity / Q000502:physiology; D005260:Female; D006801:Humans; D009129:Muscle Tonus / Q000502:physiology; D009334:Neck Muscles / Q000502:physiology*; D011187:Posture / Q000502:physiology*; D064171:Superficial Back Muscles / Q000502:physiology*; D055815:Young Adult
keywords: Ageing; Muscle stifness; Muscle tone; MyotonPRO; Myotonometry