In which direction does skin move during joint movement?

Fukui, Tsutomu; Otake, Yuko; Kondo, Takashi

doi:10.1111/srt.12248

Cited by 14 publications

(15 citation statements)

References 26 publications

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“…Partial knowledge of the relative size and direction of STA in different skin regions (Fukui et al, 2016;Stagni et al, 2005) might also be used to design marker clusters that avoid problematic areas, since not all artefacts have the same impact. This is particularly clear for the GF method, since marker position errors appear explicitly in the AoR error formulas.…”

Section: Discussionmentioning

confidence: 99%

Analytical study of the effects of soft tissue artefacts on functional techniques to define axes of rotation

Rosario

Page

Besa

2017

Journal of Biomechanics

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The accurate location of the main axes of rotation (AoR) is a crucial step in many applications of human movement analysis. There are different formal methods to determine the direction and position of the AoR, whose performance varies across studies, depending on the pose and the source of errors. Most methods are based on minimizing squared differences between observed and modelled marker positions or rigid motion parameters, implicitly assuming independent and uncorrelated errors, but the largest error usually results from soft tissue artefacts (STA), which do not have such statistical properties and are not effectively cancelled out by such methods. However, with adequate methods it is possible to assume that STA only account for a small fraction of the observed motion and to obtain explicit formulas through differential analysis that relate STA components to the resulting errors in AoR parameters. In this paper such formulas are derived for three different functional calibration techniques (Geometric Fitting, mean Finite Helical Axis, and SARA), to explain why each technique behaves differently from the others, and to propose strategies to compensate for those errors. These techniques were tested with published data from a sit-to-stand activity, where the true axis was defined using bi-planar fluoroscopy. All the methods were able to estimate the direction of the AoR with an error of less than 5°, whereas there were errors in the location of the axis of 30-40mm. Such location errors could be reduced to less than 17mm by the methods based on equations that use rigid motion parameters (mean Finite Helical Axis, SARA) when the translation component was calculated using the three markers nearest to the axis.

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Section: Discussionmentioning

confidence: 99%

Analytical study of the effects of soft tissue artefacts on functional techniques to define axes of rotation

Rosario

Page

Besa

2017

Journal of Biomechanics

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“…First, the muscle fiber length of the PC was measured movement for the skin, but movement of the skin for the bone was not measured. The skin around the joint moved to a greater extent for the bone during joint movement 25 ) , which may have caused a skin effect. Second, muscle activity was not measured.…”

Section: Discussionmentioning

confidence: 99%

Functional difference between the proximal and distal compartments of the semitendinosus muscle

et al. 2016

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[Purpose] The tendinous inscription divides the semitendinosus muscle into the proximal and distal compartments. It was hypothesized that there are functional differences between those compartments. [Subjects and Methods] Seven adult males performed knee flexion and hip extension in the prone position. An ultrasound device measured the decrease in the length of muscle fibers in the two compartments during these movements. The knee and hip joint angles were concurrently measured using a video camera. Pearson’s correlation coefficients were calculated between the decrease in muscle fiber length in each compartment and joint angle. [Results] During knee flexion, decreased muscle fiber length was significantly correlated with increased knee flexion angle. During hip extension, there were no significant correlations for either compartment. Only the decrease in muscle fiber length in the distal compartment during hip extension tended to be negative; the other decreases in muscle fiber length tended to be positive. [Conclusion] Correlations did not reveal any functional differences. However, only the distal compartment elongated during hip extension. This result might show a functional difference and could be applied in clinical contexts during hip extension.

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“…Unfortunately, the relative movement of the soft tissue and underlying bones, that is, soft tissue artefact (STA) composed of cluster deformation (non‐rigid motion, NRM) and cluster displacement (rigid motion, RM), leads the marker cluster to incorrectly represent the bone pose 7 8 . STAs have been widely investigated in human motion analysis and have exhibited significant effects on the determination of joint kinematics 9–13 . STA‐induced errors in knee kinematics were reported when measuring with different four‐marker clusters, from which it appeared that rigidifying clusters were ineffective for the reduction of STA effects 14 .…”

Section: Introductionmentioning

confidence: 99%

Effects of soft tissue artefacts on computed segmental and stifle kinematics in canine motion analysis

Lin

et al. 2020

Veterinary Record

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Skin marker-based motion analysis has been widely used to evaluate the functional performance of canine gait and posture. However, the interference of soft tissues between markers and the underlying bones (soft tissue artefacts, STAs) may lead to errors in kinematics measurements. Currently, no optimal marker attachment sites and cluster compositions are recommended for canine gait analysis. The current study aims to evaluate cluster-level STAs and the effects of cluster compositions on the computed stifle kinematics. Ten mixed-breed healthy dogs affixed with 19 retroreflective markers on the thigh and shank were enrolled. During isolated stifle passive extension, the marker trajectories were acquired with a motion capture system, and the skeletal poses were determined by integrating fluoroscopic and CT images of the bones. The cluster-level STAs were assessed, and clusters were paired to calculate the stifle kinematics. A selection of cluster compositions was useful for deriving accurate sagittal and frontal plane stifle kinematics with flexion angles below 50 per cent of the range of motion. The findings contribute to improved knowledge of canine STAs and their influence on motion measurements. The marker composition with the smallest error in describing joint kinematics is recommended for future applications and study in dogs during dynamic gait assessment.

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In which direction does skin move during joint movement?

Abstract: These findings suggest that the skin moves according to certain physiological rules.

Cited by 14 publications

References 26 publications

Analytical study of the effects of soft tissue artefacts on functional techniques to define axes of rotation

Analytical study of the effects of soft tissue artefacts on functional techniques to define axes of rotation

Functional difference between the proximal and distal compartments of the semitendinosus muscle

Effects of soft tissue artefacts on computed segmental and stifle kinematics in canine motion analysis

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