Comparative Assessment of the Effect of Various Ankle-Foot Offloading Devices on Walking Biomechanics and Metabolic Cost

Eyal Izak
Purpose:

To characterize the kinematics, kinetics, and MC during walking with three types of AFODs: CR, IW, and ZG. 



Methods:

Twenty healthy participants were recruited for a within-subject cross-over design study. Participants performed a 6-minute walk trial at a self-selected speed in four conditions: unassisted normal gait (NG), and using three unloading devices: CR, IW, and ZG. Comprehensive measurements have been done including metabolic cost by using a metabolic system (K5, COSMED, Italy), kinematics and kinetics measurements using a motion system (Vicon, UK), and a force plate. Additionally, participants provided subjective feedback by rating their level of effort, discomfort, stability perception, and device preference of use. 

One-way analysis of variance (ANOVA) for repeated measures was used to assess the effect of different AFODs compared to normal gait (NG). 

Results:

Among AFODs, ZG demonstrated the lowest MC (p0.001), fastest walking speed (p0.001) and was perceived as the most stable device (p0.05). CR were rated with the highest perceived exertion (p0.001) and lowest comfort (p=0.0021).Compared to NG, CR exhibited a significant decrease in the center of mass )CoM( fluctuation range (p=0.032). However, IW and ZG exhibited a significant increase in the CoM fluctuation range (p 0.0001 for both). Compared to other conditions, CR produced the highest vertical GRF (p0.008) at the first peak during the stance phase. ZG produced the closest vertical GRF to NG. The second peak of the vertical GRF during the stance phase was significantly reduced when comparing all AFODs to NG (p0.02) with no difference between them. The magnitude of the first peak of the anterior-posterior GRF increased significantly with CR in comparison to all other conditions (p0.0001), with no significant difference between ZG and NG. The second peak was less affected by the devices. However, a significant reduction in force (p0.0001) was exhibited with ZG in comparison to NG.

Conclusion(s):

ZG demonstrated favorable performance in most aspects, showcasing its potential to enhance gait rehabilitation when unloading is necessary. However, poor comfort and atypical sound-side ankle kinematics were evident with ZG. 

Implications:

These findings may offer valuable insights for clinicians, aiding in informed and shared decision-making regarding prescribing AFODs when weight bearing is restricted.


Funding acknowledgements:
This research received no specific funding or grant from any funding agency in the public, commercial, or not-for-profit sectors.
Keywords:
off-loading
metabolic cost
gait
Primary topic:
Disability and rehabilitation
Second topic:
Community based rehabilitation
Did this work require ethics approval?:
Yes
Name the institution and ethics committee that approved your work:
This research was approved by the Institutional Review Board, at the Technion Institute of Technology, Israel.
Provide the ethics approval number:
#108-2020
Has any of this material been/due to be published or presented at another national or international conference prior to the World Physiotherapy Congress 2025?:
No

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