Passive Mechanical Properties of Gastrocnemius Muscles of People With Ankle Contracture After Stroke

Kwah, Li Khim; Herbert, Robert D.; Harvey, L A; Diong, Joanna; Clark, Julian; Martin, Joshua H.; Clarke, Elizabeth C.; Hoang, Phu; Bilston, Lynne E.; Gandevia, Simon C.

doi:10.1016/j.apmr.2012.02.009

Cited by 65 publications

(49 citation statements)

References 32 publications

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“…Our result of a longer Achilles tendon in adolescents with spastic CP is similar to those reported in individuals 12 years post-stroke (Zhao et al, 2009), which are in contrast to studies in multiple sclerosis, spinal cord injury and 1 year post-stroke that reported no difference in Achilles tendon length to able-bodied controls Hoang et al, 2009;Kwah et al, 2012). This indicates the muscle and tendon adaptations may be dependent on the type and site of the upper motor neuron lesion and the time the lesion has been present.…”

Section: Discussioncontrasting

confidence: 55%

Medial gastrocnemius muscle fascicle active torque-length and Achilles tendon properties in young adults with spastic cerebral palsy

Barber

Barrett

Lichtwark

2012

Journal of Biomechanics

103

142

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Section: Discussioncontrasting

confidence: 55%

Medial gastrocnemius muscle fascicle active torque-length and Achilles tendon properties in young adults with spastic cerebral palsy

Barber

Barrett

Lichtwark

2012

Journal of Biomechanics

103

142

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“…Despite recent progress in magnetic resonance (MR) and ultrasound elastography (Kwah et al, 2012), there is no reliable non-invasive method to determine constitutive properties of human soft tissues in-vivo (Miller and Lu, 2013). Therefore, we adapted a method for tissue classification and material properties assignment based on the Fuzzy C-Means (FCM) algorithm.…”

Section: Methodsmentioning

confidence: 99%

Patient-specific biomechanical model as whole-body CT image registration tool

Miller

Joldes

et al. 2015

Medical Image Analysis

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Whole-body computed tomography (CT) image registration is important for cancer diagnosis, therapy planning and treatment. Such registration requires accounting for large differences between source and target images caused by deformations of soft organs/tissues and articulated motion of skeletal structures. The registration algorithms relying solely on image processing methods exhibit deficiencies in accounting for such deformations and motion. We propose to predict the deformations and movements of body organs/tissues and skeletal structures for whole-body CT image registration using patient-specific non-linear biomechanical modelling. Unlike the conventional biomechanical modelling, our approach for building the biomechanical models does not require time-consuming segmentation of CT scans to divide the whole body into non-overlapping constituents with different material properties. Instead, a Fuzzy C-Means (FCM) algorithm is used for tissue classification to assign the constitutive properties automatically at integration points of the computation grid. We use only very simple segmentation of the spine when determining vertebrae displacements to define loading for biomechanical models. We demonstrate the feasibility and accuracy of our approach on CT images of seven patients suffering from cancer and aortic disease. The results confirm that accurate whole-body CT image registration can be achieved using a patient-specific non-linear biomechanical model constructed without time-consuming segmentation of the whole-body images.

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“…However, several studies have found that the plantar-flexor passive-elasticity in the chronic SCI patients was higher than observed in the healthy age-matched participants. 24,26,46 We speculate that plantar-flexor elasticity in SCI patients increases with immobilization during the acute stage of injury (o1 year), and thereafter, elasticity gradually decreases over time due in part to the muscle atrophy observed in this study. In theory, muscle morphology influences passive tension.…”

Section: Discussionmentioning

confidence: 93%

“…[14][15][16] Three different mathematical models were fitted to the angle (θ)-torque (τ) data as previously described: [16][17][18][19][20][21][22][23][24][25][26][27] (i) Second-order polynomial (SOP) model (Equation 1)…”

Section: Discussionmentioning

confidence: 99%

Mechanical and neural changes in plantar-flexor muscles after spinal cord injury in humans

et al. 2015

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Study design: Cross-sectional study. Objectives: To determine the effect of injury duration on plantar-flexor elastic properties in individuals with chronic spinal cord injury (SCI) and spasticity. Setting: National Rehabilitation Center for Persons with Disabilities, Japan. Methods: A total of 16 chronic SCI patients (age, 33 ± 9.3 years; injury localization, C6-T12; injury duration, 11-371 months) participated. Spasticity of the ankle plantar-flexors was assessed using the Modified Ashworth Scale (MAS). The calf circumference and muscle thickness of the medial gastrocnemius (MG), lateral gastrocnemius and soleus were assessed using tape measure and ultrasonography. In addition, the ankle was rotated from 10°plantar-flexion to 20°dorsiflexion at 5 deg s −1 with a dynamometer, and the ankle angle and torque were recorded. After normalizing the data (the initial points of angle and torque were set to zero), we calculated the peak torque and energy. Furthermore, angle-torque data (before and after normalization) were fitted with a second-and fourth-order polynomial, and exponential (Sten-Knudsen) models, and stiffness indices (SI SOP, SI FOP, SI SK ) and Angle SLACK (the angle at which plantar-flexor passive torque equals zero) were calculated. The stretch reflex gain and offset were determined from 0-10°d orsiflexion at 50, 90, 120 and 150 deg s −1 . After logarithmic transformation, Pearson's correlation coefficients were calculated. Results: MAS, calf circumference, MG thickness, peak torque and SI FOP significantly decreased with injury duration (r loglog = − 0.63, − 0.69, − 0.63, − 0.53 and − 0.55, respectively, Po0.05). The peak torque and SI FOP maintained significant relationships even after excluding impacts from muscle morphology. Conclusion: Plantar-flexor elasticity in chronic SCI patients decreased with increased injury duration.

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Passive Mechanical Properties of Gastrocnemius Muscles of People With Ankle Contracture After Stroke

Cited by 65 publications

References 32 publications

Medial gastrocnemius muscle fascicle active torque-length and Achilles tendon properties in young adults with spastic cerebral palsy

Medial gastrocnemius muscle fascicle active torque-length and Achilles tendon properties in young adults with spastic cerebral palsy

Patient-specific biomechanical model as whole-body CT image registration tool

Mechanical and neural changes in plantar-flexor muscles after spinal cord injury in humans

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