Accuracy of an optical active-marker system to track the relative motion of rigid bodies

Maletsky, Lorin P.; Sun, Junyi; Morton, Nicholas A.

doi:10.1016/j.jbiomech.2006.01.017

Cited by 126 publications

(91 citation statements)

References 14 publications

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“…Kinematics of the femur, tibia, and patella were obtained using rigid body markers and a 3-camera Optotrak 3020 system (Northern Digital Inc., Waterloo, Ontario). This system has a measurement bias of 0.05° and a 95% repeatability limit of 0.67° for a rotation of 10°, and a bias of 0.03 mm and a 95% repeatability limit of 0.29 mm for a translation of 10mm [18]. The position and orientation of each cadaver femur, tibia, and patella relative to the dynamic knee simulator were recorded using a probing tip with the Optotrak system.…”

Section: Cadaver Knee Measurements and Testingmentioning

confidence: 99%

Computational Knee Ligament Modeling Using Experimentally Determined Zero-Load Lengths

Bloemker¹,

Guess²,

Maletsky³

et al. 2012

TOBEJ

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This study presents a subject-specific method of determining the zero-load lengths of the cruciate and collateral ligaments in computational knee modeling. Three cadaver knees were tested in a dynamic knee simulator. The cadaver knees also underwent manual envelope of motion testing to find their passive range of motion in order to determine the zero-load lengths for each ligament bundle. Computational multibody knee models were created for each knee and model kinematics were compared to experimental kinematics for a simulated walk cycle. One-dimensional non-linear spring damper elements were used to represent cruciate and collateral ligament bundles in the knee models. This study found that knee kinematics were highly sensitive to altering of the zero-load length. The results also suggest optimal methods for defining each of the ligament bundle zero-load lengths, regardless of the subject. These results verify the importance of the zero-load length when modeling the knee joint and verify that manual envelope of motion measurements can be used to determine the passive range of motion of the knee joint. It is also believed that the method described here for determining zero-load length can be used for in vitro or in vivo subject-specific computational models.

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Section: Cadaver Knee Measurements and Testingmentioning

confidence: 99%

Computational Knee Ligament Modeling Using Experimentally Determined Zero-Load Lengths

Bloemker¹,

Guess²,

Maletsky³

et al. 2012

TOBEJ

View full text Add to dashboard Cite

show abstract

“…This feature could be interesting for variations if used in gait training. In addition, one can be confident that the generated movements are actual movements since the motion analysis method used here has a bias of 0.05° for angle measurement, well below the minimal amplitude measured in the present study, i.e., 0.8° ± 0.3° [19].…”

Section: Discussionmentioning

confidence: 42%

Complex muscle vibration patterns to induce gait-like lower-limb movements: Proof of concept

Duclos

Kemlin²,

Lazert³

et al. 2014

J Rehabil Res Dev

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Abstract-Muscle vibrations can induce motor responses and illusions of complex movements. However, inducing gait-like cyclical movements and illusions requires the application of multiple fast alternating vibrations to lower-limb muscles. The objectives were (1) to test the feasibility of delivering complex vibrations in a time-organized manner and (2) to illustrate the possibility of inducing alternate gait-in-place-like movements using these vibrations. Patterns of vibration, produced by 12 vibrators applied bilaterally on the flexor and extensor muscle groups of the lower limbs, were based on normal gait kinematics. We tested 1 s and 2 s cycle patterns of vibration. Vibrator responses were assessed using auto-and crosscorrelations and frequency analyses based on accelerometry measurements, and compared between patterns. High auto-(>0.8) and crosscorrelation (>0.6) coefficients demonstrated a good response by the vibrators to the control signal. Vibrations induced cyclical, low-amplitude stepping-in-place movements that mimicked alternate walking movements with both legs, with 1 s and 2 s cycle durations, in one nondisabled participant and one participant with American Spinal Injury Association Impairment Scale B spinal cord injury standing, relaxed, with body-weight support. Electromechanical vibrators can deliver complex cyclical vibrations and trigger gait-like lower-limb movements. These results warrant the application of these vibration patterns on individuals with sensorimotor impairments to test their potential in gait rehabilitation.

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“…1) Kinematic Validation A 3D motion capture system (Northern Digital Inc., Optotrak Certus) was used to calibrate and validate the WA orientation measured by iWA. The system is widely used in human movement analysis and has excellent accuracy characteristics in rotational (0.04°) and linear (0.03mm) motion [20]. The iWA sensor housing was instrumented with four active Infra-red (IRED) markers which were used to identify the iWA as a rigid body using calibration routines supplied with the motion capture software.…”

Section: Discussionmentioning

confidence: 99%

An Instrumented Walking Aid to Assess and Retrain Gait

Culmer

Brooks

Strauss

et al. 2014

IEEE/ASME Trans. Mechatron.

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Abstract-An instrumented walking-aid, the iWA system, has been developed to measure kinematic and kinetic properties of walking aid (WA) use and deliver feedback to improve gait. The clinical requirements, technical specification and design of the system are developed through clinical collaboration. The development of the system is described, including hardware components and data analysis used to process the measured data for assessment. The system measurements are validated under controlled laboratory conditions. The iWA system is evaluated in a typical UK clinical environment by a participant in a rehabilitation session. The resultant data successfully capture the quality of the participant's walking aid use and agree with clinical opinion, supporting the efficacy of this approach.

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Accuracy of an optical active-marker system to track the relative motion of rigid bodies

Cited by 126 publications

References 14 publications

Computational Knee Ligament Modeling Using Experimentally Determined Zero-Load Lengths

Computational Knee Ligament Modeling Using Experimentally Determined Zero-Load Lengths

Complex muscle vibration patterns to induce gait-like lower-limb movements: Proof of concept

An Instrumented Walking Aid to Assess and Retrain Gait

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