Biomechanics of uphill walking using custom ankle-foot orthoses of three different stiffnesses.
Ankle-foot orthoses (AFOs) can provide support and improve walking ability in individuals with plantarflexor weakness. Passive-dynamic AFO stiffness can be optimized for over-ground walking, however little research exists for uphill walking, when plantarflexor contributions are key.


OBJECTIVE
Compare uphill walking biomechanics (1) between dynamic AFO users and able-bodied control subjects. (2) between injured and sound limbs (3) across different AFO stiffnesses.


METHODS
Twelve patients with unilateral limb-salvage and twelve matched, able-bodied controls underwent biomechanical gait analysis when walking up a 10° incline. Three AFO stiffnesses were tested in the patient group: Nominal (clinically prescribed), Compliant (20% less stiff), and Stiff (20% more stiff).


CONCLUSIONS
AFO users experienced less ankle motion and power generation, lower knee extensor moments, and greater hip flexion and power generation than controls during uphill walking. Despite these deviations, they walked at equivalent self-selected velocities and stride lengths. Asymmetries were present at the ankle and knee with decreased ankle motion and power, and lower knee extensor moments on the AFO limb. Stiffer AFOs increased knee joint flexion but a 40% range in AFO stiffness had few other effects on gait. Therefore, a wide range of clinically prescribed AFO stiffnesses may adequately assist uphill walking.
Center for the Intrepid, Department of Orthopaedics and Rehabilitation, Brooke Army Medical Center, Ft. Sam Houston, TX 78234, United States.
Derek J
DJ
Haight
Center for the Intrepid, Department of Orthopaedics and Rehabilitation, Brooke Army Medical Center, Ft. Sam Houston, TX 78234, United States. Electronic address: erussell.kin@gmail.com.
Elizabeth
E
Russell Esposito
Center for the Intrepid, Department of Orthopaedics and Rehabilitation, Brooke Army Medical Center, Ft. Sam Houston, TX 78234, United States.
Jason M
JM
Wilken
D000328:Adult; D000843:Ankle Joint / Q000502:physiology; D001696:Biomechanical Phenomena / Q000502:physiology; D016022:Case-Control Studies; D004867:Equipment Design; D061826:Foot Orthoses; D006801:Humans; D007719:Knee Joint / Q000502:physiology; D023821:Limb Salvage; D008297:Male; D016059:Range of Motion, Articular / Q000502:physiology; D016138:Walking / Q000502:physiology*
Ankle brace; Gait; IDEO; Incline; Limb salvage; Military