title: Effect of isometric upper-extremity exercises on the activation of core stabilizing muscles.
abstract: OBJECTIVE
  To evaluate whether isometric exercises for the upper extremities could sufficiently activate core stabilizing muscles to increase muscle strength.
  
  
  METHODS
  Cross-sectional study.
  
  
  METHODS
  Department of physical medicine and rehabilitation at a Finnish hospital.
  
  
  METHODS
  Healthy adult women (N=20).
  
  
  METHODS
  Not applicable.
  
  
  METHODS
  Peak isometric strength of the back and abdominal muscles was measured and relative loading in 5 test exercises was evaluated by surface electromyography.
  
  
  RESULTS
  The rectus abdominis and obliquus externus abdominis were activated to the greatest degree in a bilateral shoulder extension exercise and the average surface electromyographic activity was 114% and 101% compared with the amplitude elicited during the maximal isometric trunk flexion exercise. Horizontal shoulder extension elicited the greatest activation of the longissimus and multifidus muscles. In this exercise, the activity levels of the left side multifidus and longissimus muscles were 84% and 69%, respectively, compared with the level of activity elicited during trunk extension.
  
  
  CONCLUSIONS
  Of all the exercises studied, bilaterally performed isometric shoulder extension and unilaterally performed horizontal shoulder extension elicited the greatest levels of activation of the trunk musculature. Thus, it can be assumed that these exercises elicit sufficient levels of contraction of the trunk muscles for the development of their endurance and strength characteristics in rehabilitation.
authors.affiliation: Department of Health Sciences, University of Jyväskylä, Jyväskylä, Finland. sami.tarnanen@kolumbus.fi
authors.forename: Sami P
authors.initials: SP
authors.lastname: Tarnanen
authors.forename: Jari J
authors.initials: JJ
authors.lastname: Ylinen
authors.forename: Kirsti M
authors.initials: KM
authors.lastname: Siekkinen
authors.forename: Esko A
authors.initials: EA
authors.lastname: Mälkiä
authors.forename: Hannu J
authors.initials: HJ
authors.lastname: Kautiainen
authors.forename: Arja H
authors.initials: AH
authors.lastname: Häkkinen
mesh_terms: D000009:Abdominal Muscles / Q000502:physiology; D000328:Adult; D015331:Cohort Studies; D003430:Cross-Sectional Studies; D004576:Electromyography; D005081:Exercise Therapy / Q000379:methods*; D005260:Female; D006801:Humans; D007537:Isometric Contraction / Q000502:physiology*; D008875:Middle Aged; D053580:Muscle Strength / Q000502:physiology; D018482:Muscle, Skeletal / Q000502:physiology*; D004856:Postural Balance / Q000502:physiology*; D011187:Posture; D011336:Probability; D012016:Reference Values; D012047:Rehabilitation Centers; D012680:Sensitivity and Specificity; D034941:Upper Extremity