The maximum velocity of shortening during the early phases of the contraction in frog single muscle fibres

1984 ◽  
Vol 5 (5) ◽  
pp. 503-513 ◽  
Author(s):  
V. Lombardi ◽  
G. Menchetti
Keyword(s):  
Maximum Velocity ◽  
Muscle Fibres ◽  
Single Muscle ◽  
Velocity Of Shortening ◽  
Early Phases

scholarly journals Differences in maximum velocity of shortening along single muscle fibres of the frog.

1985 ◽  
Vol 365 (1) ◽  
pp. 147-163 ◽  
Author(s):  
K A Edman ◽  
C Reggiani ◽  
G te Kronnie
Keyword(s):  
Maximum Velocity ◽  
Muscle Fibres ◽  
Single Muscle ◽  
Velocity Of Shortening

scholarly journals Power Output and Force-Velocity Relationship of Live Fibres from White Myotomal Muscle of the Dogfish, Scyliorhinus Canicula

1988 ◽  
Vol 140 (1) ◽  
pp. 187-197 ◽  
Author(s):  
N. A. CURTIN ◽  
R. C. WOLEDGE
Keyword(s):  
Power Output ◽  
Maximum Velocity ◽  
Muscle Fibres ◽  
Fish Length ◽  
Skinned Fibres ◽  
Step Method ◽  
Velocity Relationship ◽  
Velocity Of Shortening ◽  
Force Velocity ◽  
Myotomal Muscle

The relationship between force and velocity of shortening and between power and velocity were examined for myotomal muscle fibre bundles from the dogfish. The maximum velocity of shortening, mean value 4.8 ± 0.2 μms−1 half sarcomere−1 (±S.E.M., N = 13), was determined by the ‘slack step’ method (Edman, 1979) and was found to be independent of fish length. The force-velocity relationship was hyperbolic, except at the high-force end where the observations were below the hyperbola fitted to the rest of the data. The maximum power output was 91 ± 14 W kg−1 wet mass (±S.E.M., N = 7) at a velocity of shortening of 1.3 ± 0.13μms−1 halfsarcomere−1 (±S.E.M., N = 7). This power output is considerably higher than that previously reported for skinned fibres (Bone et al. 1986). Correspondingly the force-velocity relationship is less curved for intact fibres than for skinned fibres. The maximum swimming speed (normalized for fish length) predicted from the observed power output of the muscle fibres decreased with increasing fish size; it ranged from 12.9 to 7.8 fish lengths s−1 for fish 0155–0.645m in length.

Post-operative effects on insulin resistance and specific tension of single human skeletal muscle fibres

1999 ◽  
Vol 97 (4) ◽  
pp. 449-455 ◽  
Author(s):  
Hans DEGENS ◽  
Mattias SOOP ◽  
Peter HÖÖK ◽  
Olle LJUNGQVIST ◽  
Lars LARSSON
Keyword(s):  
Insulin Resistance ◽  
Protein Content ◽  
Muscle Weakness ◽  
Maximum Velocity ◽  
Myofibrillar Protein ◽  
Muscle Fibres ◽  
Single Muscle ◽  
Specific Tension ◽  
Generating Capacity ◽  
Single Fibres

Surgery and accidental trauma are associated with a transient period of insulin resistance, substrate catabolism and muscle weakness. In the present study, we evaluated the changes in the force-generating capacity of chemically skinned single muscle fibres following abdominal surgery. Biopsies of the m. vastus lateralis were obtained in three patients 1 day before and 3 or 6 days after surgery. Part of the biopsy was frozen for histochemical analysis of the fibre cross-sectional area (FCSA) and myofibrillar protein content, and another part was used for single-fibre contractile measurements. All patients developed insulin resistance following surgery. The maximum velocity of unloaded shortening of single muscle fibres did not change following surgery. The FCSA did not decrease after surgery, as determined either from histochemical sections or from single fibres measured at a fixed sarcomere length of 2.76±0.09 μm (mean±S.D.). Further, the force-generating capacity of the single fibres, measured as maximal Ca2+-activated force (P0) or as P0 normalized to FCSA (specific tension), remained unchanged, as did the myofibrillar protein content of the muscle. In conclusion, the muscle weakness associated with post-operative insulin resistance is not related to a decreased specific tension or a loss of myofibrillar proteins. Other potential cellular mechanisms underlying post-operative weakness are discussed.

Elastic energy storage and release in white muscle from dogfish scyliorhinus canicula

1999 ◽  
Vol 202 (2) ◽  
pp. 135-142 ◽  
Author(s):  
F. Lou ◽  
N.A. Curtin ◽  
R.C. Woledge
Keyword(s):  
Energy Cost ◽  
White Muscle ◽  
Isometric Force ◽  
Muscle Length ◽  
Maximum Velocity ◽  
Muscle Fibres ◽  
External Work ◽  
Scyliorhinus Canicula ◽  
Velocity Of Shortening ◽  
In Series

The production of work by the contractile component (CC) and the storage and release of work in the elastic structures that act in series (the series elastic component, SEC) with the contractile component were measured using white muscle fibres from the dogfish Scyliorhinus canicula. Heat production was also measured because the sum of work and heat is equivalent to the energy cost of the contraction (ATP used). These energy fluxes were evaluated in contractions with constant-velocity shortening either during stimulation or during relaxation. The muscle preparation was tetanized for 0.6 s and shortened by 1 mm (approximately 15 % of L0) at 3.5 or 7.0 mm s-1 (approximately 15 or 30 % of V0), where L0 is the muscle length at which isometric force is greatest and V0 is the maximum velocity of shortening. In separate experiments, the stiffness of the SEC was characterized from measurements of force responses to step changes in the length of contracting muscle. Using the values of SEC stiffness, we evaluated separately the work and heat associated with the CC and with the SEC. The major findings were (1) that work stored in the SEC could be completely recovered as external work when shortening occurred during relaxation (none of the stored work being degraded into heat) and (2) that, when shortening occurred progressively later during the contraction, the total energy cost of the contraction declined towards that of an isometric contraction.

scholarly journals Twitch and Tetanic Tension during Culture of Mature Xenopus laevis Single Muscle Fibres

2001 ◽  
Vol 109 (5) ◽  
pp. 410-417 ◽  
Author(s):  
R.T. Jaspers ◽  
H.M. Feenstra ◽  
M.B.E. Lee-de Groot ◽  
P.A. Huijing ◽  
W.J. van der Laarse
Keyword(s):  
Xenopus Laevis ◽  
Muscle Fibres ◽  
Single Muscle ◽  
Tetanic Tension

scholarly journals Metabolic changes with fatigue in different types of single muscle fibres of Xenopus laevis.

1992 ◽  
Vol 448 (1) ◽  
pp. 511-523 ◽  
Author(s):  
A S Nagesser ◽  
W J van der Laarse ◽  
G Elzinga
Keyword(s):  
Xenopus Laevis ◽  
Metabolic Changes ◽  
Muscle Fibres ◽  
Single Muscle ◽  
Different Types
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