title: Sample size considerations in human muscle architecture studies.
abstract: BACKGROUND
  This report is a meta-analysis of the human muscle architecture literature that analyzes the number of muscles, number of subjects, and muscle fiber length coefficient of variation (CV) by body region.
  
  
  METHODS
  Muscle fiber length data are used to make recommendations for dissection-based architectural study sample sizes.
  
  
  RESULTS
  An average of 9 ± 10 (mean ± SD) muscles and an average of 9 ± 5 subjects were reported in the 26 studies considered. Across all studies, average fiber length CV was highly variable (18% ± 5%). This shows that sample sizes required to achieve adequate power varies by anatomical region.
  
  
  CONCLUSIONS
  Studies involving muscle architecture should consider regional variability and effect size and determine sample size accordingly.
authors.affiliation: Department of Orthopaedic Surgery, University of California San Diego, San Diego, California, USA.
authors.forename: Lori J
authors.initials: LJ
authors.lastname: Tuttle
authors.forename: Samuel R
authors.initials: SR
authors.lastname: Ward
authors.forename: Richard L
authors.initials: RL
authors.lastname: Lieber
mesh_terms: D002102:Cadaver; D016206:Databases, Bibliographic / Q000706:statistics & numerical data; D006801:Humans; D008279:Magnetic Resonance Imaging; D018482:Muscle, Skeletal / Q000000981:diagnostic imaging / Q000473:pathology; D012107:Research Design; D018401:Sample Size; D018608:Ultrasonography, Doppler