title: Knee extensor strength exhibits potential to predict function in sporadic inclusion-body myositis.
abstract: BACKGROUND
  In this study we address the challenging issue of potential use of muscle strength to predict function in clinical trials. This has immediate relevance to translational studies that attempt to improve quadriceps strength in sporadic inclusion-body myositis (sIBM).
  
  
  METHODS
  Maximum voluntary isometric contraction testing as a measure of muscle strength and a battery of functional outcomes were tested in 85 ambulatory subjects with sIBM.
  
  
  RESULTS
  Marked quadriceps weakness was noted in all patients. Strength was correlated with distance walked at 2 and 6 minutes. Additional correlations were found with time to get up from a chair, climb stairs, and step up on curbs.
  
  
  CONCLUSIONS
  Quadriceps (knee extensor) strength correlated with performance in this large cohort of sIBM subjects, which demonstrated its potential to predict function in this disease. These data provide initial support for use of muscle strength as a surrogate for function, although validation in a clinical trial is required.
authors.affiliation: Center for Gene Therapy, Nationwide Children's Hospital, 700 Children's Drive, Columbus, Ohio 43205, USA. linda.lowes@nationwidechildrens.org
authors.forename: Linda Pax
authors.initials: LP
authors.lastname: Lowes
authors.forename: Lindsay
authors.initials: L
authors.lastname: Alfano
authors.forename: Laurence
authors.initials: L
authors.lastname: Viollet
authors.forename: Xiomara Quintero
authors.initials: XQ
authors.lastname: Rosales
authors.forename: Zarife
authors.initials: Z
authors.lastname: Sahenk
authors.forename: Brian K
authors.initials: BK
authors.lastname: Kaspar
authors.forename: K Reed
authors.initials: KR
authors.lastname: Clark
authors.forename: Kevin M
authors.initials: KM
authors.lastname: Flanigan
authors.forename: Jerry R
authors.initials: JR
authors.lastname: Mendell
authors.forename: Michael P
authors.initials: MP
authors.lastname: McDermott
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D007839:Functional Laterality; D006801:Humans; D007537:Isometric Contraction / Q000502:physiology; D007719:Knee Joint / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D053580:Muscle Strength / Q000502:physiology*; D018979:Myositis, Inclusion Body / Q000473:pathology* / Q000503:physiopathology*; D011237:Predictive Value of Tests; D011597:Psychomotor Performance / Q000502:physiology; D052097:Quadriceps Muscle / Q000503:physiopathology*; D016138:Walking / Q000502:physiology