March 2015

Plantar flexion resistance alters knee flexion, foot strike in stroke patients

In the moment: O&P

By Jordana Bieze Foster

Increasing the plantar flexion resistance of an ankle foot orthosis (AFO) reduces knee hyperextension and changes foot strike pattern during gait in chronic stroke patients, according to research presented in February at the AAOP meeting in New Orleans.

A multicenter team of investigators assessed 10 patients (two women), who were an average of six years poststroke, as they walked while wearing an experimental AFO with a steel-spring design that adjusts for different degrees of plantar flexion resistance.

Increasing the resistance of the AFO was associated with a systematic response involving increased knee flexion during gait and a shift from a forefoot strike pattern to a rearfoot strike pattern.

“This indicates the importance of tuning the plantar flexion resistance of the AFO,” said Toshiki Kobayashi, PhD, a research scientist with Orthocare Innovations in Oklahoma City, OK, who presented the findings at the AAOP meeting. “In the future we should be able to tune the resistance of an AFO the way we tune the alignment of a prosthesis.”


Kobayashi T. Effect of ankle foot orthosis plantar flexion resistance on lower-limb kinematics and kinetics in patients with stroke. Presented at the American Academy of Orthotists and Prosthetists Annual Meeting and Scientific Symposium, New Orleans, February 2015.

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