Passive mechanical properties of the gastrocnemius after spinal cord injury

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

doi:10.1002/mus.23356

Cited by 31 publications

(29 citation statements)

References 32 publications

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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: 70%

“…Theoretically, both muscle and tendon arranged in series can affect the total tissue stiffness, 47 a relationship that has been experimentally confirmed in the plantar-flexors of healthy participants. 17 In contrast, Diong et al 24 observed that the Gas muscle stiffness is increased in SCI participants, whereas Olson et al 6 found that the muscle changes occur at the cell level and reflect muscle fiber transformation from Type I to Type II. In addition, Maganaris 48 showed that patellar tendon CSA, stiffness, and Young's modulus decreased significantly in chronic (18-288 months after injury) complete SCI patients.…”

Section: Discussionmentioning

confidence: 96%

“…[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%

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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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Section: Discussionmentioning

confidence: 70%

Section: Discussionmentioning

confidence: 96%

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

et al. 2015

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“…; Diong et al. ). After tracking the image sequence, linear regressions were fitted to the points marking the fascicles and cubic splines were fitted to the points marking the proximal and distal aponeuroses.…”

Section: Methodsmentioning

confidence: 98%

“…The “effective” fascicle length ( l f ; the length of a muscle fascicle projected onto the long axis of the muscle) was calculated from the product of the measured fascicle length and the cosine of the pennation angle (Diong et al. ). All tracking was performed by one investigator.…”

Section: Methodsmentioning

confidence: 99%

Passive elongation of muscle fascicles in human muscles with short and long tendons

et al. 2017

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This study tested the hypothesis that the ratio of changes in muscle fascicle and tendon length that occurs with joint movement scales linearly with the ratio of the slack lengths of the muscle fascicles and tendons. We compared the contribution of muscle fascicles to passive muscle‐tendon lengthening in muscles with relatively short and long fascicles. Fifteen healthy adults participated in the study. The medial gastrocnemius, tibialis anterior, and brachialis muscle‐tendon units were passively lengthened by slowly rotating the ankle or elbow. Change in muscle fascicle length was measured with ultrasonography. Change in muscle‐tendon length was calculated from estimated muscle moment arms. Change in tendon length was calculated by subtracting change in fascicle length from change in muscle‐tendon length. The median (IQR) contribution of muscle fascicles to passive lengthening of the muscle‐tendon unit, measured as the ratio of the change in fascicle length to the change in muscle‐tendon unit length, was 0.39 (0.26–0.48) for the medial gastrocnemius, 0.51 (0.29–0.60) for tibialis anterior, and 0.65 (0.49–0.90) for brachialis. Brachialis muscle fascicles contributed to muscle‐tendon unit lengthening significantly more than medial gastrocnemius muscle fascicles, but less than would be expected if the fascicle contribution scaled linearly with the ratio of muscle fascicle and tendon slack lengths.

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Tension-referenced measures of gastrocnemius slack length and stiffness in Parkinson's disease

et al. 2016

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Passive mechanical properties of the gastrocnemius after spinal cord injury

Abstract: People with ankle contractures after spinal cord injury have stiff gastrocnemius muscle-tendon units. It is not clear whether this reflects changes in properties of muscle fascicles or tendons.

Cited by 31 publications

References 32 publications

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

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

Passive elongation of muscle fascicles in human muscles with short and long tendons

Tension-referenced measures of gastrocnemius slack length and stiffness in Parkinson's disease

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