title: The association between muscle strength and activity limitations in patients with the hypermobility type of Ehlers-Danlos syndrome: the impact of proprioception.
abstract: The patients diagnosed with Ehlers-Danlos Syndrome Hypermobility Type (EDS-HT) are characterized by pain, proprioceptive inacuity, muscle weakness, potentially leading to activity limitations. In EDS-HT, a direct relationship between muscle strength, proprioception and activity limitations has never been studied. The objective of the study was to establish the association between muscle strength and activity limitations and the impact of proprioception on this association in EDS-HT patients.
  
  
  
  Twenty-four EDS-HT patients were compared with 24 controls. Activity limitations were quantified by Health Assessment Questionnaire (HAQ), Six-Minute Walk test (6MWT) and 30-s chair-rise test (30CRT). Muscle strength was quantified by handheld dynamometry. Proprioception was quantified by movement detection paradigm. In analyses, the association between muscle strength and activity limitations was controlled for proprioception and confounders.
  
  
  
  Muscle strength was associated with 30CRT (r = 0.67, p = <0.001), 6MWT (r = 0.58, p = <0.001) and HAQ (r = 0.63, p= <0.001). Proprioception was associated with 30CRT (r = 0.55, p < 0.001), 6MWT (r = 0.40, p = <0.05) and HAQ (r = 0.46, p < 0.05). Muscle strength was found to be associated with activity limitations, however, proprioceptive inacuity confounded this association.
  
  
  
  Muscle strength is associated with activity limitations in EDS-HT patients. Joint proprioception is of influence on this association and should be considered in the development of new treatment strategies for patients with EDS-HT. Implications for rehabilitation Reducing activity limitations by enhancing muscle strength is frequently applied in the treatment of EDS-HT patients. Although evidence regarding treatment efficacy is scarce, the current paper confirms the rationality that muscle strength is an important factor in the occurrence of activity limitations in EDS-HT patients. Although muscle strength is the most dominant factor that is associated with activity limitations, this association is confounded by proprioception. In contrast to common belief proprioception was not directly associated with activity limitations but confounded this association. Controlling muscle strength on the bases of proprioceptive input may be more important for reducing activity limitations than just enhancing sheer muscle strength.
authors.affiliation: a Faculty of Health, ACHIEVE , Center for Applied Research, University of Applied Sciences Amsterdam , Amsterdam , The Netherlands.|b Department of Rehabilitation , Academic Medical Centre, University of Amsterdam , Amsterdam , The Netherlands.
authors.forename: Mark
authors.initials: M
authors.lastname: Scheper
authors.affiliation: c Department of Rehabilitation Sciences and Physiotherapy , Ghent University , Ghent , Belgium.
authors.forename: Lies
authors.initials: L
authors.lastname: Rombaut
authors.affiliation: a Faculty of Health, ACHIEVE , Center for Applied Research, University of Applied Sciences Amsterdam , Amsterdam , The Netherlands.|b Department of Rehabilitation , Academic Medical Centre, University of Amsterdam , Amsterdam , The Netherlands.
authors.forename: Janneke
authors.initials: J
authors.lastname: de Vries
authors.affiliation: c Department of Rehabilitation Sciences and Physiotherapy , Ghent University , Ghent , Belgium.
authors.forename: Inge
authors.initials: I
authors.lastname: De Wandele
authors.affiliation: a Faculty of Health, ACHIEVE , Center for Applied Research, University of Applied Sciences Amsterdam , Amsterdam , The Netherlands.|d Reade, Amsterdam Rehabilitation Research Centre , Amsterdam , The Netherlands.
authors.forename: Martin
authors.initials: M
authors.lastname: van der Esch
authors.affiliation: a Faculty of Health, ACHIEVE , Center for Applied Research, University of Applied Sciences Amsterdam , Amsterdam , The Netherlands.
authors.forename: Bart
authors.initials: B
authors.lastname: Visser
authors.affiliation: e Center for Medical Genetics , Ghent University , Ghent , Belgium.
authors.forename: Franciska
authors.initials: F
authors.lastname: Malfait
authors.affiliation: c Department of Rehabilitation Sciences and Physiotherapy , Ghent University , Ghent , Belgium.
authors.forename: Patrick
authors.initials: P
authors.lastname: Calders
authors.affiliation: a Faculty of Health, ACHIEVE , Center for Applied Research, University of Applied Sciences Amsterdam , Amsterdam , The Netherlands.|b Department of Rehabilitation , Academic Medical Centre, University of Amsterdam , Amsterdam , The Netherlands.
authors.forename: Raoul
authors.initials: R
authors.lastname: Engelbert
mesh_terms: D000328:Adult; D004535:Ehlers-Danlos Syndrome / Q000534:rehabilitation*; D005080:Exercise Test; D005221:Fatigue / Q000150:complications; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D051346:Mobility Limitation; D015999:Multivariate Analysis; D053580:Muscle Strength; D009426:Netherlands; D010146:Pain / Q000150:complications; D011434:Proprioception; D012044:Regression Analysis; D064232:Visual Analog Scale; D055815:Young Adult
keywords: Activity limitations; Ehlers–Danlos (hypermobility type); muscle strength; musculoskeletal complaints; proprioception