Bidirectional Tuning of the AFO Stiffness

maximal ankle angular velocity in loading response in degrees

The goal of this pilot study with a pre-post design is to investigate the effects of separate
 individualization of the AFO stiffness towards plantar- and dorsiflexion in a spring-hinged
 AFO on walking compared to a spring-like AFO (3 types) having the same stiffness in both
 directions.
 
 People with a neuromuscular disease or nerve injury causing at least plantarflexor weakness
 (determined as the inability to perform 3 single heel rises), with an indication for or using
 an AFO, will be fitted with a new, custom-made spring-hinged AFO with the NEURO SWING® system
 ankle joint (Fior& Gentz, Lüneburg In Duderstadt, Germany), of which the stiffness of ventral
 and dorsal compartment of this spring-hinged AFO will be individualized. For comparison,
 measurements will be performed with three different prefab spring-like AFOs with different
 stiffness levels (but which have a similar stiffness towards plantar and dorsiflexion), and
 the participants' current AFO if applicable, and shoes-only at baseline.
 
 The main outcome parameters will be the maximal ankle plantarflexion angle, ankle angular
 velocity and knee flexion angle during the loading response, which will be measured using a
 3D gait analysis. Secondary outcomes include other gait biomechanics, walking energy cost,
 walking speed, standing balance, perceived physical functioning and perceived walking
 ability.