title: Leg muscle function and fatigue during walking in spinal muscular atrophy type 3.
abstract: BACKGROUND
  Spinal muscular atrophy (SMA) causes muscle weakness and fatigue. Better understanding of the relationship between weakness and fatigue may help identify potential targets for rehabilitation.
  
  
  METHODS
  Gait and surface electromyography (EMG) from 4 muscle groups were measured during the Six-Minute Walk Test (6MWT) in 10 ambulatory participants, aged 9-49 years. Average root mean square amplitude (RMS) of muscle activity was calculated. Strength was assessed using manual and quantitative methods.
  
  
  RESULTS
  RMS, stride length, and velocity decreased during the 6MWT. Knee flexor and hip abductor strength was associated with fatigue-related changes; overall strength correlated with disease duration; and leg strength was associated with 6MWT distance.
  
  
  CONCLUSIONS
  Clinical measures are valid in assessing fatigue and function in SMA, and these assessments can be enhanced by use of gait analysis and EMG. Disease duration and strength measures may represent further stratification refinements when enrolling patients in clinical trials.
authors.affiliation: Department of Neurology, Columbia University, 180 Fort Washington Avenue, 5th Floor, New York, NY, USA.
authors.forename: Jacqueline
authors.initials: J
authors.lastname: Montes
authors.forename: Sally
authors.initials: S
authors.lastname: Dunaway
authors.forename: Carol Ewing
authors.initials: CE
authors.lastname: Garber
authors.forename: Claudia A
authors.initials: CA
authors.lastname: Chiriboga
authors.forename: Darryl C
authors.initials: DC
authors.lastname: De Vivo
authors.forename: Ashwini K
authors.initials: AK
authors.lastname: Rao
mesh_terms: D000293:Adolescent; D000328:Adult; D002648:Child; D003430:Cross-Sectional Studies; D004576:Electromyography; D005260:Female; D005684:Gait / Q000502:physiology; D006801:Humans; D007866:Leg / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D018763:Muscle Fatigue / Q000502:physiology*; D053580:Muscle Strength / Q000502:physiology; D053581:Muscle Strength Dynamometer; D018482:Muscle, Skeletal / Q000503:physiopathology*; D009134:Muscular Atrophy, Spinal / Q000503:physiopathology*; D009460:Neurologic Examination; D016896:Treatment Outcome; D016138:Walking / Q000502:physiology*; D055815:Young Adult
keywords: fatigue; gait; muscle strength; outcome measure; six-minute walk test; spinal muscular atrophy