Dynamic characterisation of Össur Flex-Run prosthetic feet for a more informed prescription

Authors: Noroozi, S., Ong, Z.C., Khoo, M., Aslani, N. and Sewell, P.

http://eprints.bournemouth.ac.uk/29966/

url:%20http:/mc.manuscriptcentral.com/tpoi%20Email:%20tim.bach@ispoint.org

Journal: ISPO

Background: The current method of prescribing composite Energy Storing and 6 Returning (ESR) feet is subjective and is based only on the amputee’s static body 7 weight/mass.

8 Objectives: The aim is to investigate their unique design features through identifying 9 and analysing their dynamic characteristics, utilising modal analysis, to determine 10 their mode shapes, natural damping and natural frequencies. Full understanding of 11 the dynamic characteristics can inform on how to tune a foot to match an amputee’s 12 gait and body condition.

13 Methods: This paper presents the modal analysis results of the full range of Össur 14 Flex-Run running feet that are commercially available (1LO-9LO).

15 Results: It is shown that both the undamped natural frequency and stiffness increase 16 linearly from the lowest to highest stiffness category of foot. The effect of over-load 17 and under-loading on natural frequencies is also presented. The damping factor for 18 each foot has been experimentally determined and it was found to be ranging 19 between 1.5-2.0%. An analysis of the mode shapes also showed a unique design 20 feature of these feet that is hypothesised to enhance their performance.

21 Conclusions: A better understanding of the feet dynamic characteristics can help to 22 tune the feet to the user’s requirements.

23 (194 words)

This data was imported from PubMed:

Authors: Noroozi, S., Ong, Z.C., Khoo, S.Y., Aslani, N. and Sewell, P.

http://eprints.bournemouth.ac.uk/29966/

Journal: Prosthet Orthot Int

Volume: 43

Issue: 1

Pages: 62-70

eISSN: 1746-1553

DOI: 10.1177/0309364618789449

BACKGROUND:: The current method of prescribing composite running-specific energy-storing-and-returning feet is subjective and is based only on the amputee's static body weight/mass. OBJECTIVES:: The aim was to investigate their dynamic characteristics and create a relationship between these dynamic data and the prescription of foot. STUDY DESIGN:: Experimental Assessment. METHODS:: This article presents the modal analysis results of the full range of Össur Flex-Run™ running feet that are commercially available (1LO-9LO) using experimental modal analysis technique under a constant mass at 53 kg and boundary condition. RESULTS:: It was shown that both the undamped natural frequency and stiffness increase linearly from the lowest to the highest stiffness category of foot which allows for a more informed prescription of foot when tuning to a matched natural frequency. The low damping characteristics determined experimentally that ranged between 1.5% and 2.0% indicates that the feet require less input energy to maintain the steady-state cyclic motion before take-off from the ground. An analysis of the mode shapes also showed a unique design feature of these feet that is hypothesised to enhance their performance. CONCLUSION:: A better understanding of dynamic characteristics of the feet can help tune the feet to the user's requirements in promoting a better gait performance. CLINICAL RELEVANCE: The dynamic data determined from this study are needed to better inform the amputees in predicting the natural frequency of the foot prescribed. The amputees can intuitively tune the cyclic body rhythm during walking or running to match with the natural frequency. This could eventually promote a better gait performance.

This data was imported from Scopus:

Authors: Noroozi, S., Ong, Z.C., Khoo, S.Y., Aslani, N. and Sewell, P.

http://eprints.bournemouth.ac.uk/29966/

Journal: Prosthetics and Orthotics International

Volume: 43

Issue: 1

Pages: 62-70

eISSN: 1746-1553

ISSN: 0309-3646

DOI: 10.1177/0309364618789449

© The International Society for Prosthetics and Orthotics 2018. Background: The current method of prescribing composite running-specific energy-storing-and-returning feet is subjective and is based only on the amputee’s static body weight/mass. Objectives: The aim was to investigate their dynamic characteristics and create a relationship between these dynamic data and the prescription of foot. Study Design: Experimental Assessment. Methods: This article presents the modal analysis results of the full range of Össur Flex-Run ™ running feet that are commercially available (1LO–9LO) using experimental modal analysis technique under a constant mass at 53 kg and boundary condition. Results: It was shown that both the undamped natural frequency and stiffness increase linearly from the lowest to the highest stiffness category of foot which allows for a more informed prescription of foot when tuning to a matched natural frequency. The low damping characteristics determined experimentally that ranged between 1.5% and 2.0% indicates that the feet require less input energy to maintain the steady-state cyclic motion before take-off from the ground. An analysis of the mode shapes also showed a unique design feature of these feet that is hypothesised to enhance their performance. Conclusion: A better understanding of dynamic characteristics of the feet can help tune the feet to the user’s requirements in promoting a better gait performance. Clinical relevance: The dynamic data determined from this study are needed to better inform the amputees in predicting the natural frequency of the foot prescribed. The amputees can intuitively tune the cyclic body rhythm during walking or running to match with the natural frequency. This could eventually promote a better gait performance.

This data was imported from Web of Science (Lite):

Authors: Noroozi, S., Ong, Z.C., Khoo, S.Y., Aslani, N. and Sewell, P.

http://eprints.bournemouth.ac.uk/29966/

Journal: PROSTHETICS AND ORTHOTICS INTERNATIONAL

Volume: 43

Issue: 1

Pages: 62-70

eISSN: 1746-1553

ISSN: 0309-3646

DOI: 10.1177/0309364618789449

The data on this page was last updated at 05:14 on July 22, 2019.