title: Kinematic analysis of runners with achilles mid-portion tendinopathy.
abstract: BACKGROUND
  Despite anecdotal evidence linking overpronation to the onset of Achilles tendinopathy (AT), there is little conclusive evidence of a particular movement pattern of the lower extremity associated with this injury. Therefore, the objective of the present study was to observe differences in the kinematic profiles of healthy runners (CON) and runners with mid-portion Achilles tendinopathy (ATG).
  
  
  METHODS
  In this cross-sectional analysis, 48 male height and weight matched subjects were invited to participate: 27 with mid-portion Achilles tendon pain and 21 asymptomatic controls. Subjects underwent lower extremity clinical examination, then ran barefoot for 10-trials at a self-selected pace. A 3D motion capture system analysed tri-plane kinematic data for the lower extremity.
  
  
  RESULTS
  The ATG displayed significantly greater sub-talar joint eversion displacement during mid-stance of the running gait (13 +/- 3 degrees vs. 11 +/- 3 degrees; p = 0.04). Trends were observed such that the ATG showed lower peak dorsiflexion velocity (300 +/- 39 degrees/s vs. 330 +/- 59 degrees/s; p = 0.08) and greater overall frontal plane ankle joint range of motion (45 degrees +/- 7 vs. 41 degrees +/- 7; p = 0.09).
  
  
  CONCLUSIONS
  We found an increase in eversion displacement of the sub-talar joint in runners with Achilles mid-portion tendinopathy. Based on the findings from this study, there is evidence that devices used to control sub-talar eversion may be warranted in patients with Achilles mid-portion tendinopathy who demonstrate over-pronation during mid-stance of the running gait.
authors.affiliation: University of British Columbia, Experimental Medicine Program, 602-1355 West 14th, Vancouver V6H1R2, Canada. mryan76@gmail.com
authors.forename: Michael
authors.initials: M
authors.lastname: Ryan
authors.forename: Stefan
authors.initials: S
authors.lastname: Grau
authors.forename: Inga
authors.initials: I
authors.lastname: Krauss
authors.forename: Christian
authors.initials: C
authors.lastname: Maiwald
authors.forename: Jack
authors.initials: J
authors.lastname: Taunton
authors.forename: Thomas
authors.initials: T
authors.lastname: Horstmann
mesh_terms: D000125:Achilles Tendon / Q000503:physiopathology*; D000328:Adult; D000843:Ankle Joint / Q000503:physiopathology; D001696:Biomechanical Phenomena; D016022:Case-Control Studies; D003430:Cross-Sectional Studies; D006801:Humans; D008297:Male; D011403:Pronation / Q000502:physiology; D016059:Range of Motion, Articular / Q000502:physiology; D012420:Running / Q000502:physiology*; D013640:Tarsal Joints / Q000503:physiopathology; D052256:Tendinopathy / Q000503:physiopathology*