The effect of prolonged inactivity upon the contraction characteristics of fast and slow mammalian twitch muscle (cat)

Davis, Cynthia J.; Montgomery, A.

doi:10.1113/jphysiol.1977.sp011970

Cited by 29 publications

(12 citation statements)

References 31 publications

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“…As a result of denervation, adult cat slow and fast hind limb muscles show reduced speed of contraction (Syrovy et al 1972;Kean et al 1974). Prolonged inactivity induced the same changes in cat muscles (Davis & Montgomery 1977). Immobilization did not lead to any significant changes in the speed o€ contraction in hind limb muscles of the guinea pig (Maier et al 1976).…”

Section: Discussionmentioning

confidence: 99%

Contractile Properties of Extracular Muscle in Cats Reared With Monocular Lid Closure and Artificial Squint

Lennerstrand

Hanson

1979

Acta Ophthalmologica

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Kittens were raised with amblyopia by monocular lid suture or esotropia by transection of extraocular muscles in one eye at the age of 2--3 weeks. Isometric contractions in the inferior oblique muscle were recorded at 20 weeks or at adult age, and the results were compared with those of similarly aged cats with normal visual development. The speed of contraction and the fatigue resistance was reduced in the lid sutured animals. In the esotropic cats studied, fatigue resistance was also reduced but the speed of contraction did not change much. It is suggested that the postnatal eye muscle development can be modified by manipulation of the visual input at an early age. Presumably the impaired binocular vision in the lid sutured and esotropic cats reduced the demand for fusion vergences, and this might be reflected in the changes of eye muscle properties. In monocularly lid sutured cats, eye muscle changes were the same on both sides, suggesting that amblyopia per se did not affect eye muscle development.

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Section: Discussionmentioning

confidence: 99%

Contractile Properties of Extracular Muscle in Cats Reared With Monocular Lid Closure and Artificial Squint

Lennerstrand

Hanson

1979

Acta Ophthalmologica

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“…The force decreased disproportionately more than the wet weight of the disused muscle (Eccles, 1941;Fischbach and Robbins, 1969;Davis and Montgomery, 1977). The slight to moderate diminution in force, present on day 8, disappeared gradually, probably because of a gradual increase in cross-sectional area of the muscle fibres.…”

Section: Electrical Activity At a Fixed Force Of 5 Kgmentioning

confidence: 91%

Transient decrease in number of motor units after immobilisation in man.

Fuglsang-Frederiksen¹,

Scheel²

1978

Journal of Neurology, Neurosurgery & Psychiatry

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SUMMARY On the day after the removal of a long leg cast, when the patient could just bend his knee, the electrical activity in the disused quadriceps muscle showed changes that indicated a reduction in the number of motor units. At 10 to 75%/, of maximum force the number of turns and the mean amplitude of the needle-recorded EMG were reduced in the disused muscle. Eight days later, when half the initial loss of force had been regained, the electrical activity was normal. The electrical activity produced during a constant force of 5 kg did not differ in the disused and in the contralateral muscle. From the findings in normal subjects it was deduced that the compensatory increase in turns in the EMG pattern to be expected from the decrease in cross-sectional area of the muscle fibres was within the error of the method. The transient decrease in the number of turns and in mean amplitude of the EMG of the disused muscle are an indication of the plasticity of the motor system.Inactivity of a muscle results in a diminished force usually attributed to atrophy of the muscle fibres (Adams, 1975). Our study was initiated by the observation that the force of the atrophic quadriceps muscle increased from 40% to 80% of the force of the contralateral muscle within one week after immobilisation. This rate of increase did not seem compatible with the time required for recovery of the cross-sectional area of the muscle fibres. To distinguish between a diminished cross-sectional area of muscle fibres and a reduced number of activated motor units, we analysed the pattern of electrical activity in the muscles of eight patients during recovery after immobilisation. The difference in the EMG pattern obtained during a force adjusted relative to the maximum force and during a standard force allows this differentiation to be made (Fuglsang-Frederiksen and MWnsson, 1975;Fuglsang-Frederiksen et al., 1977). Patients and methodEight patients, six men aged 20-32 years and two women aged 20 and 42 years, were investigated. The right or the left leg was immobilised in a long

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“…Accordingly, marked atrophy of type 1 fibers in the quadriceps, after knee injury or immobilization by plaster casts, have been shown during the first month, and atrophy of both types after 2–6 months of immobilization [14, 15]. Experimental studies in cats and rats showed that the strength decreased disproportionately more than the weight in a disused muscle [16, 17]. A combination of T/A analysis and MFCV could contribute to the assessment in the study of the weakness of a disused muscle.…”

Section: Discussionmentioning

confidence: 99%

Quadriceps Atrophy after Knee Traumatisms and Immobilization: Electrophysiological Assessment

Cruz-Martínez

Ramirez²,

Arpa³

2000

Eur Neurol

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Automatic analysis of EMG (T/A analysis) and invasive muscle fiber conduction velocity in situ (MFCV) were performed in 15 patients after traumatic lesions of the knee and immobilization with quadriceps atrophy. T/A analysis showed transient reduced number of turns, consistent with inhibition of quadriceps motoneurons, that recovered within the first 2 weeks after the plaster cast had been removed. MFCV was significantly slowed and showed a gradual improvement, reaching normal values after 6 weeks. These results suggest that decrement in activated motor units may be the cause of the disproportionate weakness of the quadriceps muscle on the first days after immobilization by the plaster cast. The recovery of MFCV was related with functional improvement of strength after the first weeks.

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The effect of prolonged inactivity upon the contraction characteristics of fast and slow mammalian twitch muscle (cat)

Cited by 29 publications

References 31 publications

Contractile Properties of Extracular Muscle in Cats Reared With Monocular Lid Closure and Artificial Squint

Contractile Properties of Extracular Muscle in Cats Reared With Monocular Lid Closure and Artificial Squint

Transient decrease in number of motor units after immobilisation in man.

Quadriceps Atrophy after Knee Traumatisms and Immobilization: Electrophysiological Assessment

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