title: Gastrocnemius medialis muscle architecture and physiological cross sectional area in adult males with Duchenne muscular dystrophy.
abstract: OBJECTIVE
  To describe muscle size and architecture of the gastrocnemius medialis (GM) muscle in eleven adult males with Duchenne Muscular Dystrophy (DMD, age 24.5±5.4 years), and a control group of eleven males without DMD (CTRL, age 22.1±0.9 years).
  
  
  METHODS
  GM anatomical cross sectional area (ACSA), volume (VOL), physiological cross sectional area (PCSA), fascicle length (Lf) and pennation angle (θ) were assessed using B-Mode Ultrasonography. GM ACSA was measured at 25, 50 and 75% of muscle length (Lm), from which VOL was calculated. At 50% of Lm, sagittal plane images were analysed to determine GM Lf and θ. GM PCSA was calculated as: VOL/Lf. The ratio of Lf and Lm was also calculated.
  
  
  RESULTS
  GM ACSA at 50% Lm, VOL and PCSA were smaller in DMD males compared to CTRL males by 36, 47 and 43%, respectively (P<0.01). There were no differences in Lf and θ. GM Lm was 29% shorter in DMD compared to CTRL. Lf/Lm was 29% longer in DMD (P<0.01).
  
  
  CONCLUSIONS
  Unlike previous data in children with DMD, our results show significant atrophy in adult males with DMD, and no change in Lf or θ. The shorter Lm may have implications for joint flexibility.
authors.affiliation: Institute for Performance Research, Department of Exercise and Sport Science, Manchester Metropolitan University Cheshire, CW1 5DU, UK.
authors.forename: C I
authors.initials: CI
authors.lastname: Morse
authors.affiliation: Institute for Performance Research, Department of Exercise and Sport Science, Manchester Metropolitan University Cheshire, CW1 5DU, UK.|The Neuromuscular Centre, Winsford, Cheshire CW7 4EH, UK.
authors.forename: J
authors.initials: J
authors.lastname: Smith
authors.affiliation: Institute for Performance Research, Department of Exercise and Sport Science, Manchester Metropolitan University Cheshire, CW1 5DU, UK.
authors.forename: A
authors.initials: A
authors.lastname: Denny
authors.affiliation: Institute for Performance Research, Department of Exercise and Sport Science, Manchester Metropolitan University Cheshire, CW1 5DU, UK.
authors.forename: J
authors.initials: J
authors.lastname: Tweedale
authors.affiliation: Institute for Performance Research, Department of Exercise and Sport Science, Manchester Metropolitan University Cheshire, CW1 5DU, UK.
authors.forename: N D
authors.initials: ND
authors.lastname: Searle
mesh_terms: D000328:Adult; D000375:Aging; D019412:Anatomy, Cross-Sectional; D001827:Body Height; D001835:Body Weight; D006801:Humans; D008297:Male; D018482:Muscle, Skeletal / Q000000981:diagnostic imaging / Q000473:pathology*; D020388:Muscular Dystrophy, Duchenne / Q000000981:diagnostic imaging / Q000473:pathology*; D014463:Ultrasonography; D055815:Young Adult