Fig 1.
Abbreviations: vAFO, ventral shell Ankle Foot Othosis.
Fig 2.
Picture of the spring-hinged ventral shell Ankle-Foot Orthosis, including possible adjustments using the hinge.
The hinge allows: A, the stiffness to be varied towards dorsal flexion and plantar flexion; B, adjustment of the alignment of the ventral shell with respect to the foot; C, the range of motion to be varied, although this is also dependent of the spring inserted (stiffer springs allow less range of motion). Figs adapted from Fior & Gentz.
Fig 3.
Representation of relevant phases of the gait cycle.
Phases of the gait cycle were defined as i) stance: initial contact to toe-off; ii) step: initial contact to contralateral initial contact; iii) single support (SS): contralateral toe-off to contralateral initial contact. Definitions of specific gait events and mean timing [%gait cycle]: i) contralateral toe-off (cTO) [11%]; ii) midstance (MSt): the moment that the malleolus marker of the contralateral leg passed the malleolus marker of the ipsilateral leg [33%]; iii) contralateral initial contact (cIC) [50%]; iv) toe-off (TO) [64%]; v) timing of minimal knee flexion angle during single support (peak knee extension angle) (TKEpk): [38%]. Abbreviations: cTO, contralateral toe-off; cIC, contralateral initial contact; IC, initial contact; TKEpk, timing of peak knee extension angle; MSt, midstance; SS, single support; TO, toe-off.
Table 1.
Baseline participant characteristics (n = 15).
Table 2.
Baseline passive range of motion and spasticity values of relevant joints and muscles of the most affected leg (n = 15).
Fig 4.
Mean (n = 15) of the most relevant gait parameters as a function of the gait cycle.
Vertical lines indicate timing of toe-off (with similar timing for stiff and flexible vAFOs).
Table 3.
Results of generalized estimating equation analyses for relevant gait parameters, with positive values representing flexion angles, internal extension moments, and power generation.
Fig 5.
Mean (n = 15) net internal ankle moment and ankle power for walking with different degrees of vAFO stiffness, with mean vAFO contributions as a function of the gait cycle.
The area underneath the power curves (panel D-F) represents the net ankle work and vAFO work.
Table 4.
Results of generalized estimating equation analyses for hip, knee, and ankle work.
Fig 6.
Overview of individual net energy cost responses.
The x-axis represents baseline (i.e. shoes-only) net energy cost values and the y-axis indicates the change in net energy cost as a result of walking with each vAFO. Vertically aligned dots thus represent the same participant. Abbreviations: vAFO, ventral shell ankle-foot orthosis
Table 5.
Results of generalized estimating equation analyses for walking speed and energy cost.
Table 6.
Mechanical properties of the Ankle Foot Orthoses.