The Effects of Passive Ankle-Foot Orthotic Devices’ Stiffness – Application and Limitation of 2D Inverted Pendulum Gait Model
This paper presents a pilot study for the development of a lumped parameter model that can facilitate the interpretation of gait data and design AFOs. A 2-D kinematic link model was constructed first and then adapted into a lumped parameter model with inverted pendulum approach. A patient with ankle disability was recruited and performed three walks with different ankle stiffness support: no AFO, medium-stiff (3.6 N·m/deg) AFOs, and stiff (4.5 N·m/deg) AFOs. An inertia measurement unit (IMU) system was used to measure the sagittal kinematics of the impaired and unimpaired limbs, and the data collected was used as inputs for the proposed gait model. Good agreement between observed and predicted swing time of the unimpaired side based on given AFO stiffness was achieved.
KeywordsInverted pendulum AFO stiffness Swing time
- Rogers JC, Irrgang JJ (2003) Measures of adult lower extremity function: The American Academy of Orthopedic Surgeons Lower Limb Questionnaire, The Activities of Daily Living Scale of the Knee Outcome Survey (ADLS), Foot Function Index (FFI), Functional Assessment System (FAS), Harris Hip Score (HHS), Index of Severity for Hip Osteoarthritis (ISH), Index of Severity for Knee Osteoarthritis (ISK), Knee Injury and Osteoarthritis Outcome Score (KOOS), and Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC™). Arthritis Care Res 49(S5)CrossRefGoogle Scholar