• Michael Ryan Michael Ryan
  • Stefan Grau Stefan Grau
  • Inga Krauss Inga Krauss
  • Christian Maiwald Christian Maiwald
  • Jack Taunton Jack Taunton
  • Thomas Horstmann Thomas Horstmann

Despite anecdotal evidence linking overprotion 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). Materials and Methods: In this cross-sectiol alysis, 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 examition, then ran barefoot for 10-trials at a self-selected pace. A 3D motion capture system alysed 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 ᠳ degrees vs. 11 ᠳ degrees; p = 0.04). Trends were observed such that the ATG showed lower peak dorsiflexion velocity (300 ᠳ9 degrees/s vs. 330 ᠵ9 degrees/s; p = 0.08) and greater overall frontal plane ankle joint range of motion (45 degrees ᠷ vs. 41 degrees ᠷ; p = 0.09). Conclusion: 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-protion during mid-stance of the running gait.