Design of an automated device to measure sagittal plane stiffness of an articulated ankle-foot orthosis

Toshiki Kobayashi, Kam Lun Leung, Yasushi Akazawa, Hisashi Naito, Masao Tanaka, Stephen W. Hutchins

Research output: Journal article publicationJournal articleAcademic researchpeer-review

19 Citations (Scopus)


The purpose of this study was to design a new automated stiffness measurement device which could perform a simultaneous measurement of both dorsi-and plantarflexion angles and the corresponding resistive torque around the rotational centre of an articulated ankle-foot orthosis (AAFO). This was achieved by controlling angular velocities and range of motion in the sagittal plane. The device consisted of a hydraulic servo fatigue testing machine, a torque meter, a potentiometer, a rotary plate and an upright supporter to enable an AAFO to be attached to the device via a surrogate shank. The accuracy of the device in reproducing the range of motion and angular velocity was within 4 and 1 respectively in the range of motion of 30° (15° plantarflexion to 15° dorsiflexion) at the angular velocity of 10°/s, while that in the measurement of AAFO torque was within 8 at the 0° position. The device should prove useful to assist an orthotist or a manufacturer to quantify the stiffness of an AAFO and inform its clinical use.
Original languageEnglish
Pages (from-to)439-448
Number of pages10
JournalProsthetics and Orthotics International
Issue number4
Publication statusPublished - 1 Dec 2010


  • Ankle-foot orthosis (AFO)
  • mechanical test
  • stiffness

ASJC Scopus subject areas

  • Rehabilitation
  • Health Professions (miscellaneous)


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