title: Near-infrared spectroscopy during exercise and recovery in children with juvenile dermatomyositis.
abstract: BACKGROUND
  We hypothesized that microvascular disturbances in muscle tissue play a role in the reduced exercise capacity in juvenile dermatomyositis (JDM).
  
  
  METHODS
  Children with JDM, children with juvenile idiopathic arthritis (clinical controls), and healthy children performed a maximal incremental cycloergometric test from which normalized concentration changes in oxygenated hemoglobin (Δ[O2 Hb]) and total hemoglobin (Δ[tHb]) as well as the half-recovery times of both signals were determined from the vastus medialis and vastus lateralis muscles using near-infrared spectroscopy.
  
  
  RESULTS
  Children with JDM had lower Δ[tHb] values in the vastus medialis at work rates of 25%, 50%, 75%, and 100% of maximal compared with healthy children; the increase in Δ[tHb] with increasing intensity seen in healthy children was absent in children with JDM. Other outcome measures did not differ by group.
  
  
  CONCLUSIONS
  The results suggest that children with JDM may experience difficulties in increasing muscle blood volume with more strenuous exercise.
authors.affiliation: Child Development and Exercise Center, Wilhelmina Children's Hospital, University Medical Center Utrecht, Room KB.02.056.0, P.O. Box 85090, NL-3508 AB Utrecht, The Netherlands.
authors.forename: G Esther A
authors.initials: GE
authors.lastname: Habers
authors.forename: Rogier
authors.initials: R
authors.lastname: De Knikker
authors.forename: Marco
authors.initials: M
authors.lastname: Van Brussel
authors.forename: Erik
authors.initials: E
authors.lastname: Hulzebos
authors.forename: Dick F
authors.initials: DF
authors.lastname: Stegeman
authors.forename: Annet
authors.initials: A
authors.lastname: Van Royen
authors.forename: Tim
authors.initials: T
authors.lastname: Takken
mesh_terms: D000293:Adolescent; D002648:Child; D003882:Dermatomyositis / Q000378:metabolism* / Q000503:physiopathology; D015444:Exercise / Q000502:physiology*; D005080:Exercise Test; D005260:Female; D006801:Humans; D008297:Male; D009119:Muscle Contraction / Q000502:physiology*; D010101:Oxygen Consumption / Q000502:physiology; D052097:Quadriceps Muscle / Q000098:blood supply / Q000378:metabolism* / Q000503:physiopathology; D019265:Spectroscopy, Near-Infrared; D055815:Young Adult