Affordable clinical gait analysis: an assessment of the marker tracking accuracy of a new low-cost optical 3D motion analysis system

Bruce Carse, Barry Meadows, Roy Bowers, Philip Rowe

Research output: Contribution to journalLiterature review

60 Citations (Scopus)

Abstract

3D motion analysis represents a method of collecting objective, accurate and repeatable gait data, however the high cost of equipment inhibits its widespread use in routine clinical practice. OBJECTIVE: To determine the marker tracking accuracy of a new low-cost optical 3D motion analysis system. Comparative between-system study. SETTING: Clinical motion analysis laboratories. METHODS: A rigid cluster of four reflective markers was used to compare a low-cost Optitrack 3D motion analysis system against two more expensive systems (Vicon 612 and Vicon MX). Accuracy was measured by comparing the mean vector magnitudes (between each combination of markers) for each system, and reliability was measured through the coefficients of variation (CV). Gaps in the marker trajectories, which are considered undesirable, were also counted. RESULTS: In terms of accuracy, the largest disagreement between mean vector magnitudes for Optitrack and Vicon MX was 2.2%. The largest disagreement between Vicon 612 and Vicon MX was 2.1%. Regarding reliability, the mean CV was lowest in Vicon MX (0.3%) and similar in the Vicon 612 (2.5%) and Optitrack (2.3%) systems. The number of trajectory gaps for the Vicon MX, Vicon 612 and Optitrack systems were; zero, six and 11 respectively.
The Optitrack system provides a low-cost 3D motion analysis system that can offer marker tracking accuracy and reliability which is comparable with an older and still widely used system (Vicon 612). Further development work is required before Optitrack can be used for full 3D gait analysis by physiotherapists and other health professionals.
LanguageEnglish
Pages347-351
Number of pages5
JournalPhysiotherapy
Early online date6 Jun 2013
DOIs
Publication statusPublished - 2013

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Gait analysis
Gait
Costs and Cost Analysis
Costs
Trajectories
Physical Therapists
Motion analysis
Health
Equipment and Supplies

Keywords

  • clinical gait analysis
  • marker tracking
  • accuracy
  • low-cost
  • 3D
  • motion analysis system

Cite this

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title = "Affordable clinical gait analysis: an assessment of the marker tracking accuracy of a new low-cost optical 3D motion analysis system",
abstract = "3D motion analysis represents a method of collecting objective, accurate and repeatable gait data, however the high cost of equipment inhibits its widespread use in routine clinical practice. OBJECTIVE: To determine the marker tracking accuracy of a new low-cost optical 3D motion analysis system. Comparative between-system study. SETTING: Clinical motion analysis laboratories. METHODS: A rigid cluster of four reflective markers was used to compare a low-cost Optitrack 3D motion analysis system against two more expensive systems (Vicon 612 and Vicon MX). Accuracy was measured by comparing the mean vector magnitudes (between each combination of markers) for each system, and reliability was measured through the coefficients of variation (CV). Gaps in the marker trajectories, which are considered undesirable, were also counted. RESULTS: In terms of accuracy, the largest disagreement between mean vector magnitudes for Optitrack and Vicon MX was 2.2{\%}. The largest disagreement between Vicon 612 and Vicon MX was 2.1{\%}. Regarding reliability, the mean CV was lowest in Vicon MX (0.3{\%}) and similar in the Vicon 612 (2.5{\%}) and Optitrack (2.3{\%}) systems. The number of trajectory gaps for the Vicon MX, Vicon 612 and Optitrack systems were; zero, six and 11 respectively. The Optitrack system provides a low-cost 3D motion analysis system that can offer marker tracking accuracy and reliability which is comparable with an older and still widely used system (Vicon 612). Further development work is required before Optitrack can be used for full 3D gait analysis by physiotherapists and other health professionals.",
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Affordable clinical gait analysis : an assessment of the marker tracking accuracy of a new low-cost optical 3D motion analysis system. / Carse, Bruce; Meadows, Barry; Bowers, Roy; Rowe, Philip.

In: Physiotherapy, 2013, p. 347-351.

Research output: Contribution to journalLiterature review

TY - JOUR

T1 - Affordable clinical gait analysis

T2 - Physiotherapy

AU - Carse, Bruce

AU - Meadows, Barry

AU - Bowers, Roy

AU - Rowe, Philip

N1 - Copyright © 2013 Chartered Society of Physiotherapy. Published by Elsevier Ltd. All rights reserved.

PY - 2013

Y1 - 2013

N2 - 3D motion analysis represents a method of collecting objective, accurate and repeatable gait data, however the high cost of equipment inhibits its widespread use in routine clinical practice. OBJECTIVE: To determine the marker tracking accuracy of a new low-cost optical 3D motion analysis system. Comparative between-system study. SETTING: Clinical motion analysis laboratories. METHODS: A rigid cluster of four reflective markers was used to compare a low-cost Optitrack 3D motion analysis system against two more expensive systems (Vicon 612 and Vicon MX). Accuracy was measured by comparing the mean vector magnitudes (between each combination of markers) for each system, and reliability was measured through the coefficients of variation (CV). Gaps in the marker trajectories, which are considered undesirable, were also counted. RESULTS: In terms of accuracy, the largest disagreement between mean vector magnitudes for Optitrack and Vicon MX was 2.2%. The largest disagreement between Vicon 612 and Vicon MX was 2.1%. Regarding reliability, the mean CV was lowest in Vicon MX (0.3%) and similar in the Vicon 612 (2.5%) and Optitrack (2.3%) systems. The number of trajectory gaps for the Vicon MX, Vicon 612 and Optitrack systems were; zero, six and 11 respectively. The Optitrack system provides a low-cost 3D motion analysis system that can offer marker tracking accuracy and reliability which is comparable with an older and still widely used system (Vicon 612). Further development work is required before Optitrack can be used for full 3D gait analysis by physiotherapists and other health professionals.

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