Shortening velocity extrapolated to zero load and unloaded shortening velocity of whole rat skeletal muscle.

Claflin, Dennis R.

doi:10.1113/jphysiol.1985.sp015589

Cited by 72 publications

(64 citation statements)

References 15 publications

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“…Akster, Granzier & ter Keurs (1985) found a value of 160 kN/m2 in perch red head muscle. Claflin & Faulkner (1985) and Ranatunga (1984) found values between 150 and 160 kN/m2 in rat soleus at 20 0C (which also contains fast fibres).…”

Section: Activation Of Red Muscle Bundlesmentioning

confidence: 96%

“…The parameters for the hyperbola were iteratively chosen so as to minimize the squared errors in velocity between the chosen hyperbola and the data (as in Claflin & Faulkner, 1985). Because Because passive tension did not appear to be temperature dependent, the lowest load utilized on a given bundle was approximately the same at both 10 and 20 'C.…”

Section: Measurement Of Vmax Of Red Bundlesmentioning

confidence: 99%

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The influence of temperature on mechanics of red muscle in carp.

Rome

Sosnicki

1990

The Journal of Physiology

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SUMMARY1. We measured the influence of temperature on maximum velocity of shortening (Vmax) of red muscle in carp in order to better understand the influence of temperature on locomotory performance.2. A stable red muscle bundle preparation containing about 100 muscle fibres was developed. The bundles could not be activated directly by electrical stimulation, but rather contained sufficient nervous tissue so that acetylcholine released from the nerve terminals caused activation of the muscle. A high level of activation was achieved (116 kN/m2) by adding a combination of a 1 mM-caffeine and 10-5 g/ml eserine to physiological Ringer solution and electrically stimulating the preparation.3. Force-velocity characteristics were determined at 10 and 20 0C by the force clamp method. The data were well fitted by a hyperbola not constrained to pass through P0 = 1 (where P0 is the isometric force). The mean Vmax at 10 'C was 3-55+0-26 muscle lengths/s (ML/s) (n = 6) and at 20 0C, 5-71 +0-29 ML/s (n = 6).The mean Q10 for Vmax was 1-63 + 0-07 (n = 6). The a/P0* (Hill constant) and P.* (where Po* is the extrapolated load at zero velocity) were 0-49 + 0-06 (n = 6) and *19 +0-04 (n = 6) respectively at 10 0C and 0-29+0-06 (n = 6) and 1-51 +0-20 (n = 6) respectively at 20 0C.4. The mean Q10 for maximum isometric tension was 113 + 0-02 (n = 6). The maximal power generation was 59-7 + 2-3 W/kg (n = 6) at 10 'C and 94-3 + 3-2 W/kg (n = 6) at 20 0C representing a Q10 of 1-58. The Q10 is less than the product of Q10s for P0 and Vm.. because of the greater curvature of the force-velocity curve at 20 0C.5. The 1-63-fold higher Vmax at 200C than at 10 0C enables fish to swim with a 1-6-fold faster muscle shortening velocity, V, at the higher temperature. Thus at both 10 and 20 0C, red muscle is used only over the same narrow range of V/Vmax (0-184-36),where isolated muscle experiments suggest that power and efficiency are maximal.Thus V/Vmax appears to be an effective design constraint which limits the range of velocities over which muscle is used in vivo at different temperatures.

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Section: Activation Of Red Muscle Bundlesmentioning

confidence: 96%

Section: Measurement Of Vmax Of Red Bundlesmentioning

confidence: 99%

The influence of temperature on mechanics of red muscle in carp.

Rome

Sosnicki

1990

The Journal of Physiology

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“…Force measurements (in Newtons) were normalized to muscle cross-sectional area (cm 2 ). The unloaded shortening velocity (V 0 ) of isolated extraocular muscles was determined with slack tests (Claflin and Faulkner, 1985). Briefly, muscles were stimulated to contract maximally for 350 msec; 250 msec into the stimulation train the muscle was shortened abruptly, causing force to fall to zero.…”

Section: Methodsmentioning

confidence: 99%

“…The difference between in vitro activation and natural recruitment of extraocular muscle fibers also may explain the lack of an in vivo correlate for the impaired V 0 . In heterogeneous muscles, such as the extraocular muscles, V 0 is a measure of the speed of shortening of the fastest muscle fibers present (Claflin and Faulkner, 1985). In the extraocular muscles these fibers should be those expressing the ultrafast extraocular musclespecific myosin isoform, i.e., the orbital singly innervated fibers (OSIF).…”

Section: Functional Deficitsmentioning

confidence: 99%

Functional and Genomic Changes in the Mouse Ocular Motor System in Response to Light Deprivation from Birth

McMullen¹,

Andrade²,

Stahl³

2004

J. Neurosci.

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Previous studies have suggested that abnormal visual experience early in life induces ocular motor abnormalities. The purpose of this study was to determine how visual deprivation alters the function and gene expression profile of the ocular motor system in mice. We measured the effect of dark rearing on eye movements, gene expression in the oculomotor nucleus, and contractility of isolated extraocular muscles. In vivo eye movement recordings showed decreased gains for optokinetic and vestibulo-ocular reflexes, confirming an effect of dark rearing on overall ocular motor function. Saccade peak velocities were preserved, however, arguing that the quantitative changes in these reflexes were not secondary to limitations in force generation. Using microarrays and quantitative PCR, we found that dark rearing shifted the oculomotor nucleus transcriptome to a state of delayed/arrested development. The expression of 132 genes was altered by dark rearing; these genes fit in various functional categories (signal transduction, transcription/translation control, metabolism, synaptic function, cytoskeleton), and some were known to be associated with neuronal development and plasticity. Extraocular muscle contractility was impaired by dark rearing to a greater extent than expected from the in vivo ocular motility studies: changes included decreased force and shortening speed and evidence of abnormal excitability. The results indicate that normal development of the mouse ocular motor system and its muscles requires visual experience. The transcriptional pattern of arrested development may indicate that vision is required to establish the adult pattern, but it also may represent the plastic response of oculomotor nuclei to abnormal extraocular muscles.

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“…7); it seems that faster HAR played a role in reducing HCV sufficiently, resulting in similar HCV among younger adults while walking faster in comparison to older adults. The previous studies [38][39][40][41][42] found that maximal unloaded shortening velocity in fast-twitch fibers was faster in comparison to slow-twitch fibers and suggested that fast-twitch fibers produced higher force in comparison to slow-twitch fibers in a given time [38][39][40][41]. Also, many studies demonstrated a direct relationship between muscle force and EMG activity [36,[43][44][45][46].…”

Section: Hamstring Activation Rate In Older Adults Was Lower Than Thementioning

confidence: 99%

Relationship between hamstring activation rate and heel contact velocity: Factors influencing age-related slip-induced falls

Lockhart¹,

Kim²

2006

Gait & Posture

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The purpose of this research was to determine whether a decreased hamstring activation rate among the elderly is responsible for a higher horizontal heel contact velocity and increased likelihood of slip-induced falls compared to their younger counterparts. Twenty-eight subjects from two age groups (14 young and 14 old) walked across a linear walking track with embedded force platforms while wearing a fall arresting harness attached to an overhead arresting rig for safety. In order to obtain realistic unexpected slip-induced fall data, a soapy vinyl floor surface was hidden from the subjects and unexpectedly introduced. Synchronized kinematics, kinetic and electromyography (EMG) analyses during the heel contact phase of the gait cycle while walking over slippery and nonslippery floor surfaces were examined in the study. Normalized EMG data were examined in terms of hamstring activation rate and evaluated with heel contact velocity and friction demand characteristic (as measured by peak required coefficient of friction (RCOF)) on the dry vinyl floor surface. Furthermore, slip parameters (i.e. slip distances and slipping velocity) were assessed on the soapy vinyl floor surface. The results indicated that younger adults' hamstring activation rate was higher than older adults, whereas younger adults' heel contact velocity was not different from older adults. These results suggested that heel contact velocity in younger adults was sufficiently reduced before the heel contact phase of the gait cycle. This could be due to the outcome of higher hamstring activation rate in younger adults in comparison to older adults. However, lower friction demand (peak RCOF), shorter slip distances, slower peak sliding heel velocity and more falls among older adults suggested that the slip initiation characteristics were not the only factors contributing to slip-induced falls among the elderly.

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Shortening velocity extrapolated to zero load and unloaded shortening velocity of whole rat skeletal muscle.

Cited by 72 publications

References 15 publications

The influence of temperature on mechanics of red muscle in carp.

The influence of temperature on mechanics of red muscle in carp.

Functional and Genomic Changes in the Mouse Ocular Motor System in Response to Light Deprivation from Birth

Relationship between hamstring activation rate and heel contact velocity: Factors influencing age-related slip-induced falls

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