title: Is the Sørensen test valid to assess muscle fatigue of the trunk extensor muscles?
abstract: BACKGROUND
  Very few studies have quantified the degree of fatigue characterized by the decline in the maximal voluntary contraction (MVC) force of the trunk extensors induced by the widely used Sørensen test.
  
  
  OBJECTIVE
  Measure the degree of fatigue of the trunk extensor muscles induced by the Sørensen test.
  
  
  METHODS
  Eighty young healthy subjects were randomly divided into a control group (CG) and an experimental group (EG), each including 50% of the two genders. The EG performed an isometric MVC of the trunk extensors (pre-fatigue test) followed by the Sørensen test, the latter being immediately followed by another MVC (post-fatigue test). The CG performed only the pre- and post-fatigue tests without any exertion in between.
  
  
  RESULTS
  The comparison of the pre- and post-fatigue tests revealed a significant (P< 0.05) decrease in MVC force normalized by body mass (-13%) in the EG, whereas a small increase occurred in the CG (+2.7%, P= 0.001).
  
  
  CONCLUSIONS
  This study shows that the Sørensen test performed until failure in a young healthy population results in a reduced ability of the trunk extensor muscles to generate maximal force, and indicates that this test is valid for the assessment of fatigue in trunk extensor muscles.
authors: Department of Sport and Rehabilitation Sciences, University of Liege, Liege, Belgium.|Department of Physical Medicine and Rehabilitation, Liege University Hospital Center, Liege, Belgium.
authors: Christophe
authors: C
authors: Demoulin
authors: Department of Sport and Rehabilitation Sciences, University of Liege, Liege, Belgium.
authors: Mathieu
authors: M
authors: Boyer
authors: Laboratory of Applied Biology and Research Unit in Neurophysiology, Université Libre de Bruxelles, Brussels, Belgium.
authors: Jacques
authors: J
authors: Duchateau
authors: Department of Sport and Rehabilitation Sciences, University of Liege, Liege, Belgium.|Department of Physical Medicine and Rehabilitation, Liege University Hospital Center, Liege, Belgium.
authors: Stéphanie
authors: S
authors: Grosdent
authors: Department of Sport and Rehabilitation Sciences, University of Liege, Liege, Belgium.
authors: Boris
authors: B
authors: Jidovtseff
authors: Department of Sport and Rehabilitation Sciences, University of Liege, Liege, Belgium.|Department of Physical Medicine and Rehabilitation, Liege University Hospital Center, Liege, Belgium.
authors: Jean-Michel
authors: JM
authors: Crielaard
authors: Department of Sport and Rehabilitation Sciences, University of Liege, Liege, Belgium.|Department of Physical Medicine and Rehabilitation, Liege University Hospital Center, Liege, Belgium.
authors: Marc
authors: M
authors: Vanderthommen
mesh_terms: D000293:Adolescent; D000328:Adult; D064131:Back Muscles / Q000502:physiology*; D016022:Case-Control Studies; D004576:Electromyography; D005260:Female; D006801:Humans; D007537:Isometric Contraction / Q000502:physiology*; D008297:Male; D018763:Muscle Fatigue / Q000502:physiology*; D010807:Physical Endurance / Q000502:physiology; D010808:Physical Examination / Q000379:methods*; D011897:Random Allocation; D055815:Young Adult
keywords: Isometric exercise; fatigability; low back pain; muscle endurance; spinal muscles