title: Achilles Tendon Adaptation During Transition to a Minimalist Running Style.
abstract: BACKGROUND
  Achilles tendons (ATs) adapt to increased loading generated by long-term adoption of a minimalist shoe running style. There may be difference in the chronology and extent of adaptation between the sexes.
  
  
  OBJECTIVE
  To learn the chronology of AT adaptations in female and male runners who transitioned to a minimalist running style through a planned, progressive 12-wk transition program.
  
  
  METHODS
  Prospective cohort study of well-trained, traditionally shod runners who transitioned to minimalist shoe running.
  
  
  METHODS
  Repeated laboratory assessment at baseline and 3, 12, and 24 wk after initiating transition program.
  
  
  METHODS
  Fifteen women and 7 men (of 29 enrolled) completed the study.
  
  
  METHODS
  The authors used diagnostic ultrasound and isokinetic dynamometry to generate a force elongation curve and its derivatives at each time point.
  
  
  RESULTS
  Greater adaptations were observed in men than in women, with men generating more force and having greater increases in CSA, stiffness, and Young's modulus and less elongation after 12 wk of training.
  
  
  CONCLUSIONS
  Men demonstrated changes in AT properties that were consistent with increased loading of the triceps surae during exercise. The women demonstrated far smaller changes. Further investigation is warranted to understand when adaptations may occur in women and the implications of altered AT mechanical properties for performance and injury risk.
authors.forename: Michael F
authors.initials: MF
authors.lastname: Joseph
authors.forename: Katherine
authors.initials: K
authors.lastname: Histen
authors.forename: Julia
authors.initials: J
authors.lastname: Arntsen
authors.forename: Lauren
authors.initials: L
authors.lastname: L'Hereux
authors.forename: Carmine
authors.initials: C
authors.lastname: Defeo
authors.forename: Derek
authors.initials: D
authors.lastname: Lockwood
authors.forename: Todd
authors.initials: T
authors.lastname: Scheer
authors.forename: Craig R
authors.initials: CR
authors.lastname: Denegar
mesh_terms: D000125:Achilles Tendon / Q000000981:diagnostic imaging / Q000502:physiology*; D000222:Adaptation, Physiological; D000704:Analysis of Variance; D001696:Biomechanical Phenomena; D005260:Female; D006801:Humans; D008297:Male; D053580:Muscle Strength / Q000502:physiology; D053581:Muscle Strength Dynamometer; D018482:Muscle, Skeletal / Q000000981:diagnostic imaging / Q000502:physiology*; D011446:Prospective Studies; D012420:Running / Q000502:physiology*; D012737:Sex Factors; D012775:Shoes / Q000145:classification*; D014463:Ultrasonography; D055815:Young Adult
keywords: material properties; mechanical characteristics; training response