Muscle, the Motor

Partridge, Lloyd D.; Benton, Laurel A.

doi:10.1002/cphy.cp010203

Cited by 39 publications

(25 citation statements)

References 377 publications

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“…The model parameters, poles position and pure time added delay, of the FFDR obtained from torque and MMG are not statistically different confirming previous data from the cat gastrocnemius (Orizio et al, 2000) and supporting the view that the changes in muscle transverse dimensions during contraction represent an aspect of the motor response associated inversely with the changes in muscle length producing tension at the tendon (Partridge and Benton, 1981). These results are different from the comparison of the time relationship between the force and laser detected MMG during muscle tetanic stimulation (Orizio et al, 2003b).…”

Section: Torque and Mmg Dynamic Responsessupporting

confidence: 84%

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Muscle-joint unit transfer function derived from torque and surface mechanomyogram in humans using different stimulation protocols

Orizio

Solomonow

Diemont

et al. 2008

Journal of Neuroscience Methods

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Section: Torque and Mmg Dynamic Responsessupporting

confidence: 84%

“…The detection and the measure of this phenomenon allow the characterisation of the mechanical activity of the muscle (Partridge and Benton, 1981). The electrical signal monitoring the muscle surface movement is named "surface mechanomyogram" (MMG) (Orizio et al, 2003a) and can be generated by a laser distance sensor.…”

Section: Introductionmentioning

confidence: 99%

Muscle-joint unit transfer function derived from torque and surface mechanomyogram in humans using different stimulation protocols

Orizio

Solomonow

Diemont

et al. 2008

Journal of Neuroscience Methods

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“…5) indicates that the surface MMG is linked to speci®c aspects of the forcegeneration process. This con®rms that the production of tension at the tendon is always coupled with muscle dimensional changes, as reported previously (Partridge and Benton 1981;Winter 1990;Orizio et al 1999).…”

Section: Analysis Of Mmg and Comparison With The Force Signalsupporting

confidence: 53%

“…In particular, the d 2 F/dt 2 observed during the contraction phase of the single twitch has been compared to the MMG p-p value (Takamori et al 1971). The rationale behind this comparison arises from the fact that during isometric muscle activity the force-generation process is paralleled by changes in muscle thickness (Partridge and Benton 1981). This can be explained by the fact that during isometric contractions, muscle ®bres shorten (Griths 1991;Narici et al 1996).…”

Section: Preliminary Considerationsmentioning

confidence: 99%

Surface mechanomyogram reflects the changes in the mechanical properties of muscle at fatigue

et al. 1999

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The contractile properties of muscle are usually investigated by analysing the force signal recorded during electrically elicited contractions. The electrically stimulated muscle shows surface oscillations that can be detected by an accelerometer; the acceleration signal is termed the surface mechanomyogram (MMG). In the study described here we compared, in the human tibialis anterior muscle, changes in the MMG and force signal characteristics before, and immediately after fatigue, as well as during 6 min of recovery, when changes in the contractile properties of muscle occur. Fatigue was induced by sustained electrical stimulation. The final aim was to evaluate the reliability of the MMG as a tool to follow the changes in the mechanical properties of muscle caused by fatigue. Because of fatigue, the parameters of the force peak, the peak rate of force production and the peak of the acceleration of force production (d2F/dt2) decreased, while the contraction time and the half-relaxation time (1/2-RT) increased. The MMG peak-to-peak (p-p) also decreased. The attenuation rate of the force oscillation amplitude and MMG p-p at increasing stimulation frequency was greater after fatigue. With the exception of 1/2-RT, all of the force and MMG parameters were restored within 2 min of recovery. A high correlation was found between MMG and d2F/dt2 in un-fatigued muscle and during recovery. In conclusion, the MMG reflects specific aspects of muscle mechanics and can be used to follow the changes in the contractile properties of muscle caused by localised muscle fatigue.

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“…It is also assumed there is a linear mechanical response from the MU after a single neural impulse. This premise has been questioned (Partridge and Benton, 1981). A nerve impulse from the parent motoneuron may have a variable effect on the individual fibers of the MU, depending on previous activity in the MU and the activity of other MUs within the muscle (Burke et al, 1976;Demieville and Partridge, 1980).…”

Section: Twitch Tensionsmentioning

confidence: 99%

Internal Organization in the Human Jaw Muscles

Hannam

McMillan

1994

Critical Reviews in Oral Biology & Medicine

155

102

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The human jaw muscles are essential to mastication and play an important part in craniofacial growth. They contribute to dental and articular forces, deform the mandible, and, like other tissues, are subject to disorders, often manifested as pain. The literature describes how their contraction is controlled by the nervous system, and how their general structure and function contribute to craniofacial biology, but there has been little appraisal of their internal organization. Most of these muscles are not simple; they are multipennate, complexly layered, and divided by aponeuroses. This arrangement provides substantial means for differential contraction. In many ways, jaw muscle fibers are intrinsically dissimilar from those found in other skeletal muscles, because they are arranged in homogeneous clusters and generally reveal type I or type II histochemical profiles. Most are type I and are distributed preferentially in the anterior and deeper parts of the jaw closers. Additionally, most motor unit (MU) territories are smaller than those in the limbs. There is circumstantial evidence for intramuscular partitioning based in part on innervation by primary muscle nerve branches. During normal function. MU recruitment and the rate coding of MU firing in human jaw muscles follow the general principles established for the limbs, but even here they differ in important respects. Jaw muscle MUs do not have stable force recruitment thresholds and seem to rely more on rate coding than on sequential unit recruitment to grade the amplitude of muscle contraction. Unlike those in the limbs, their twitch tensions correlate weakly with MU fatiguability and contraction speed, probably because there are so few slow, fatigue-resistant MUs in the jaw muscles. Moreover, the type I fibers that are present in such large numbers do not contract as slowly as normally expected. To complicate matters, estimation of jaw MU twitch tensions is extremely difficult, because it is affected by the location used to measure the twitch, the background firing rate, muscle coactivation, and regional, intramuscular mechanics. Finally, there have been very few systematic studies of jaw MU reflex behavior. The most recent have concentrated on exteroceptive suppression and suggest that MU inhibition following intra- and perioral stimulation depends on the location of the MU, its background firing rate, the timing of the stimulus, and the task used to drive the unit. Task dependency is a common feature of human jaw MU behavior, reflecting interaction between peripheral sensory information from orofacial and muscle afferents and corticobulbar drive.(ABSTRACT TRUNCATED AT 400 WORDS)

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Muscle, the Motor

Abstract: The sections in this article are: Representation of Muscle Properties Dimensions Used Models Real Motor Systems Summary Properties of the Contractile Unit Passive Mechanical Contributions Response to Neural Signals … Show more

Cited by 39 publications

References 377 publications

Muscle-joint unit transfer function derived from torque and surface mechanomyogram in humans using different stimulation protocols

Muscle-joint unit transfer function derived from torque and surface mechanomyogram in humans using different stimulation protocols

Surface mechanomyogram reflects the changes in the mechanical properties of muscle at fatigue

Internal Organization in the Human Jaw Muscles

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