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Reducing rigid-body error in a functional technique to determine ankle joint axes

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Functional methods of finding joint axes of rotation involve tracking the movement of one bone at a joint relative to another and subsequent calculation of the joint axis position and orientation from the locations of skin-mounted markers. van den Bogert et al. proposed a functional method of deter-mining the non-weight bearing axes of the ankle joint complex... The tech-nique implemented an optimisation algorithm to fit a kinematic model of the subtalar and talocrural joints to the experimentally ac-quired motion data... Soft tissue movement and associated marker movement was re-ported to be a significant source of error... The aim of the present study was to investigate how this skin movement error might be reduced through a better selection of marker positions... Skin marker movement during motion was estimated for all combinations of three markers located on the shank and all combinations of three markers located on the foot... The skin marker movement error, averaged over all time frames and all subjects, varied with different combinations of markers and different static trials (range 0.96–2.55 mm for foot, 1.10–7.83 mm for shank)... A reduction in error was achieved when calculations were based on a marker set different from that used by van den Bogert et al. (Figure 1)... The best combination of markers for the foot in the present study was posterior heel distal, posterior heel proximal (wand marker), and sustentaculum tali, with a non-weight-bearing static reference... For the shank, the best marker combination was head of fibula, anterior tibia, and lateral shank (wand marker), with weight-bearing static reference... Skin movement error in tracking ankle joint motion can be reduced through a better selection of marker positions... This in turn should lead to a more accurate prediction of the motion axes of the ankle joint complex.

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Skin marker movement error during the full range of ankle movement.
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Figure 1: Skin marker movement error during the full range of ankle movement.

Mentions: The skin marker movement error, averaged over all time frames and all subjects, varied with different combinations of markers and different static trials (range 0.96–2.55 mm for foot, 1.10–7.83 mm for shank). A reduction in error was achieved when calculations were based on a marker set different from that used by van den Bogert et al. (Figure 1). The best combination of markers for the foot in the present study was posterior heel distal, posterior heel proximal (wand marker), and sustentaculum tali, with a non-weight-bearing static reference. For the shank, the best marker combination was head of fibula, anterior tibia, and lateral shank (wand marker), with weight-bearing static reference.


Reducing rigid-body error in a functional technique to determine ankle joint axes
Skin marker movement error during the full range of ankle movement.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2562122&req=5

Figure 1: Skin marker movement error during the full range of ankle movement.
Mentions: The skin marker movement error, averaged over all time frames and all subjects, varied with different combinations of markers and different static trials (range 0.96–2.55 mm for foot, 1.10–7.83 mm for shank). A reduction in error was achieved when calculations were based on a marker set different from that used by van den Bogert et al. (Figure 1). The best combination of markers for the foot in the present study was posterior heel distal, posterior heel proximal (wand marker), and sustentaculum tali, with a non-weight-bearing static reference. For the shank, the best marker combination was head of fibula, anterior tibia, and lateral shank (wand marker), with weight-bearing static reference.

View Article: PubMed Central - HTML

AUTOMATICALLY GENERATED EXCERPT
Please rate it.

Functional methods of finding joint axes of rotation involve tracking the movement of one bone at a joint relative to another and subsequent calculation of the joint axis position and orientation from the locations of skin-mounted markers. van den Bogert et al. proposed a functional method of deter-mining the non-weight bearing axes of the ankle joint complex... The tech-nique implemented an optimisation algorithm to fit a kinematic model of the subtalar and talocrural joints to the experimentally ac-quired motion data... Soft tissue movement and associated marker movement was re-ported to be a significant source of error... The aim of the present study was to investigate how this skin movement error might be reduced through a better selection of marker positions... Skin marker movement during motion was estimated for all combinations of three markers located on the shank and all combinations of three markers located on the foot... The skin marker movement error, averaged over all time frames and all subjects, varied with different combinations of markers and different static trials (range 0.96–2.55 mm for foot, 1.10–7.83 mm for shank)... A reduction in error was achieved when calculations were based on a marker set different from that used by van den Bogert et al. (Figure 1)... The best combination of markers for the foot in the present study was posterior heel distal, posterior heel proximal (wand marker), and sustentaculum tali, with a non-weight-bearing static reference... For the shank, the best marker combination was head of fibula, anterior tibia, and lateral shank (wand marker), with weight-bearing static reference... Skin movement error in tracking ankle joint motion can be reduced through a better selection of marker positions... This in turn should lead to a more accurate prediction of the motion axes of the ankle joint complex.

No MeSH data available.