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

Barber, Lee; Barrett, Rod; Lichtwark, Glen A.

doi:10.1016/j.jbiomech.2012.07.018

Cited by 103 publications

(150 citation statements)

References 40 publications

(56 reference statements)

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“…Because the muscles were maximally excited, the most likely candidate is a decrease in specific tension. Consistent with our hypothesis and previous indirect assessments in human studies (2,3), passive force and stiffness of GA and PL were increased markedly at reference length (90°a nkle and knee angle) in the spastic rats. This indicates stiffer MTUs in the spastic rats because anatomical dimensions were unaffected by spasticity (Table 1).…”

Section: Discussionsupporting

confidence: 92%

“…Previously, this mutant rat model has been used for neural studies exclusively (7,39,44). The mechanical properties of the spastic rat calf muscles found in the present study are consistent with the reduced functional range of motion and increased stiffness reported clinically in human limbs affected by spasticity (17,31,32,40), and the narrower active lengthforce curves estimated in in vivo studies on human GA (2,15,16). Thus the spastic rat model used in the present study mimics several important features of spasticity in human patients, and may be used to elucidate the mechanisms responsible for changes in muscle and limb mechanical properties observed in patients with spasticity.…”

Section: Discussionsupporting

confidence: 89%

“…The absolute optimum length of GA was also lower because the absolute MTU length of GA at reference length was the same in the two groups (Table 1). These findings are consistent with length-force characteristics on the basis of net ankle joint moments and ultrasound imaging of spastic GA (2,15,16). The lower optimum length and narrower length-force curve can be explained by a number of factors: shorter muscle belly, fewer sarcomeres in series, stiffer and/or shorter tendon, or a decreased distribution of mean sarcomere length between fibers.…”

Section: Discussionsupporting

confidence: 83%

mentioning

confidence: 83%

“…Spastic GA was found to be stiffer than normally developed in such studies (2,3). The active lengthforce curve of the spastic GA was narrower and the optimum length was shifted to a shorter fascicle length than in normally developed GA (2,15,16). However, estimating length-force characteristics from joint moments can be misleading because this is the net effect of forces exerted by several MTUs and passive structures around the joint, which depend on their moment arms (11,30).…”

mentioning

confidence: 98%

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Muscle-specific changes in length-force characteristics of the calf muscles in the spastic Han-Wistar rat

Olesen

Jensen

Uhlendorf

et al. 2014

Journal of Applied Physiology

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Olesen AT, Jensen BR, Uhlendorf TL, Cohen RW, Baan GC, Maas H. Muscle-specific changes in length-force characteristics of the calf muscles in the spastic Han-Wistar rat. J Appl Physiol 117: 989-997, 2014. First published September 4, 2014 doi:10.1152/japplphysiol.00587.2014.-The purpose of the present study was to investigate muscle mechanical properties and mechanical interaction between muscles in the lower hindlimb of the spastic mutant rat. Length-force characteristics of gastrocnemius (GA), soleus (SO), and plantaris (PL) were assessed in anesthetized spastic and normally developed Han-Wistar rats. In addition, the extent of epimuscular myofascial force transmission between synergistic GA, SO, and PL, as well as between the calf muscles and antagonistic tibialis anterior (TA), was investigated. Active length-force curves of spastic GA and PL were narrower with a reduced maximal active force. In contrast, active length-force characteristics of spastic SO were similar to those of controls. In reference position (90°ankle and knee angle), higher resistance to ankle dorsiflexion and increased passive stiffness was found for the spastic calf muscle group. At optimum length, passive stiffness and passive force of spastic GA were decreased, whereas those of spastic SO were increased. No mechanical interaction between the calf muscles and TA was found. As GA was lengthened, force from SO and PL declined despite a constant muscle-tendon unit length of SO and PL. However, the extent of this interaction was not different in spastic rats. In conclusion, the effects of spasticity on length-force characteristics were muscle specific. The changes observed for GA and PL muscles are consistent with the changes in limb mechanics reported for human patients. Our results indicate that altered mechanics in spastic rats cannot be attributed to differences in mechanical interaction, but originate from individual muscular structures. muscle spasticity; mechanical properties; myofascial force transmission; muscle stiffness MUSCLE SPASTICITY HAS BEEN defined as a "velocity-depended resistance to stretch" (24) and arises secondary to upper motoneuron lesions with cerebral palsy and stroke as the most common examples (12). Individuals suffering from spasticity typically experience muscle weakness, enhanced joint stiffness, increased muscle tone, reduced range of joint motion, increased antagonistic co-contraction, and exaggerated reflexes (1,3,6,12,13,32,41,48). These effects severely impair the ability to perform daily activities, and treatment is often needed.To asses whether some of these symptoms are related to altered mechanical properties of muscle-tendon units (MTUs), passive and active length-force characteristics have been estimated as joint moment as a function of gastrocnemius (GA) fascicle length. Spastic GA was found to be stiffer than normally developed in such studies (2, 3). The active lengthforce curve of the spastic GA was narrower and the optimum length was shifted to a shorter fascicle length than in normally deve...

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Section: Discussionsupporting

confidence: 92%

Section: Discussionsupporting

confidence: 89%

Section: Discussionsupporting

confidence: 83%

mentioning

confidence: 83%

mentioning

confidence: 98%

See 3 more Smart Citations

Muscle-specific changes in length-force characteristics of the calf muscles in the spastic Han-Wistar rat

Olesen

Jensen

Uhlendorf

et al. 2014

Journal of Applied Physiology

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Determinants of muscle preservation in individuals with cerebral palsy across the lifespan: a narrative review of the literature

Verschuren

Smorenburg

Luiking

et al. 2018

J cachexia sarcopenia muscle

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In individuals with cerebral palsy (CP), smaller muscle and atrophy are present at young age. Many people with CP also experience a decline in gross motor function as they age, which might be explained by the loss of muscle mass. The clinical observation of muscle wasting has prompted a comparison with sarcopenia in older adults, and the term accelerated musculoskeletal ageing is often used to describe the hallmark phenotype of CP through the lifespan. However, there has been very little research emphasis on the natural history of ageing with CP and even less with respect to the determinants or prevention of muscle loss with CP. Considering the burgeoning interest in the science of muscle preservation, this paper aims to (i) describe the characteristics of accelerated musculoskeletal ageing in people with CP, (ii) describe the pathophysiology of sarcopenia and parallels with CP, and (iii) discuss possible therapeutic approaches, based on established approaches for sarcopenia.

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Atypical triceps surae force and work patterns underlying gait in children with cerebral palsy

Ebrahimi

Schwartz

Martin

et al. 2022

Journal Orthopaedic Research

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The purpose of this study was to quantitatively assess Achilles tendon mechanical behavior during gait in children with cerebral palsy (CP). We used a newly designed noninvasive sensor to measure Achilles tendon force in 11 children with CP (4F, 8–16 years old) and 15 typically developing children (controls) (9F, 8–17 years old) during overground walking. Mechanical work loop plots (force‐displacement plots) were generated by combining muscle‐tendon kinetics, kinematics, and EMG activity to evaluate the Achilles tendon work generated about the ankle. Work loop patterns in children with CP were substantially different than those seen in controls. Notably, children with CP showed significantly diminished work production at their preferred speed compared to controls at their preferred speed and slower speeds. Despite testing a heterogeneous population of children with CP, we observed a homogenous spring‐like muscle‐tendon behavior in these participants. This is in contrast with control participants who used their plantar flexors like a motor during gait. Statement of Clinical Significance: These data demonstrate the potential for using skin‐mounted sensors to objectively evaluate muscle contributions to work production in pathological gait.

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

Cited by 103 publications

References 40 publications

Muscle-specific changes in length-force characteristics of the calf muscles in the spastic Han-Wistar rat

Muscle-specific changes in length-force characteristics of the calf muscles in the spastic Han-Wistar rat

Determinants of muscle preservation in individuals with cerebral palsy across the lifespan: a narrative review of the literature

Atypical triceps surae force and work patterns underlying gait in children with cerebral palsy

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