Scaling of muscle performance during escape responses in the fish myoxocephalus scorpius L

1998 ◽  
Vol 201 (7) ◽  
pp. 913-923 ◽  
Author(s):  
R James ◽  
I A Johnston
Keyword(s):  
Power Output ◽  
Muscle Power ◽  
The Body ◽  
Shortening Velocity ◽  
Scaling Relationships ◽  
Muscle Shortening ◽  
Length Changes ◽  
Escape Responses ◽  
Myoxocephalus Scorpius ◽  
Muscle Power Output

Fast-starts associated with escape responses were studied in short-horn sculpin (Myoxocephalus scorpius L.), ranging from 5.5 to 32 cm in total length (L). Electromyography and sonomicrometry were used simultaneously to measure muscle activation and length changes, respectively, in the superficial layers of fast muscle in rostral myotomes. Escape responses consisted of a half tailbeat to bend the body into a C-shape (C-bend), another half tailbeat (contralateral contraction), followed by one or two more tailbeats and/or a gliding phase. The scaling relationships for both muscle strain and shortening duration differed between the C-bend and the contralateral contraction. As a result, relative muscle shortening velocity (V/V0) scaled as -1.18L1.06 for the C-bend and as 1.23L-0. 66 for the contralateral contraction. Therefore, the scaling relationships for muscle shortening velocity varied throughout the time course of the escape response. Muscle power output was determined by using the work-loop technique to subject isolated muscle fibres to in vivo strain and stimulation patterns. Plots of the instantaneous muscle forces and velocities achieved during the contralateral contraction were found to deviate from the steady-state force-velocity relationship. Maximum instantaneous muscle power output was independent of body size, with mean maximum values of 307 and 222 W kg-1 wet muscle mass for the C-bend and the contralateral contraction, respectively. <P>

scholarly journals Modelling Muscle Power Output in a Swimming Fish

1990 ◽  
Vol 148 (1) ◽  
pp. 395-402 ◽  
Author(s):  
JOHN D. ALTRINGHAM ◽  
IAN A. JOHNSTON
Keyword(s):  
Power Output ◽  
Muscle Power ◽  
Fish Swimming ◽  
Active Muscle ◽  
Cycle Frequency ◽  
Fibre Bundles ◽  
Length Changes ◽  
Myoxocephalus Scorpius ◽  
Myotomal Muscle ◽  
Muscle Power Output

Intact, electrically excitable fibre bundles were isolated from the fast and slow myotomal muscle of the bullrout (Myoxocephalus scorpius L.). Power output was measured under conditions simulating their activity in a fish swimming at different speeds. Preparations were subjected to sinusoidal length changes of ±5% of resting length, and stimulated briefly during each cycle. The number and timing of stimuli were adjusted at each cycle frequency to maximise power output. Maximum power was produced at 5–7 Hz for fast fibres (25–35 W kg−1) and 2 Hz for slow fibres (5–8 Wkg−1). Under these conditions, pre-stretch of active muscle provides an important mechanism for storing potential energy for release during the shortening part of the cycle.

Slow muscle power output of yellow- and silver-phase European eels (Anguilla anguilla L.): changes in muscle performance prior to migration

2001 ◽  
Vol 204 (7) ◽  
pp. 1369-1379 ◽  
Author(s):  
D.J. Ellerby ◽  
I.L. Spierts ◽  
J.D. Altringham
Keyword(s):  
Life History ◽  
Power Output ◽  
Muscle Power ◽  
Anguilla Anguilla ◽  
Slow Muscle ◽  
The Body ◽  
Body Axis ◽  
Power Outputs ◽  
Stimulus Offset ◽  
Muscle Power Output

Eels swim in the anguilliform mode in which the majority of the body axis undulates to generate thrust. For this reason, muscle function has been hypothesised to be relatively uniform along the body axis relative to some other teleosts in which the caudal fin is the main site of thrust production. The European eel (Anguilla anguilla L.) has a complex life cycle involving a lengthy spawning migration. Prior to migration, there is a metamorphosis from a yellow (non-migratory) to a silver (migratory) life-history phase. The work loop technique was used to determine slow muscle power outputs in yellow- and silver-phase eels. Differences in muscle properties and power outputs were apparent between yellow- and silver-phase eels. The mass-specific power output of silver-phase slow muscle was greater than that of yellow-phase slow muscle. Maximum slow muscle power outputs under approximated in vivo conditions were 0.24 W kg(−)(1) in yellow-phase eel and 0.74 W kg(−)(1) in silver-phase eel. Power output peaked at cycle frequencies of 0.3-0.5 Hz in yellow-phase slow muscle and at 0.5-0.8 Hz in silver-phase slow muscle. The time from stimulus offset to 90 % relaxation was significantly greater in yellow- than in silver-phase eels. The time from stimulus onset to peak force was not significantly different between life-history stages or axial locations. Yellow-phase eels shifted to intermittent bursts of higher-frequency tailbeats at a lower swimming speed than silver-phase eels. This may indicate recruitment of fast muscle at low speeds in yellow-phase eels to compensate for a relatively lower slow muscle power output and operating frequency.

Muscle dynamics in skipjack tuna: timing of red muscle shortening in relation to activation and body curvature during steady swimming

1999 ◽  
Vol 202 (16) ◽  
pp. 2139-2150 ◽  
Author(s):  
R.E. Shadwick ◽  
S.L. Katz ◽  
K.E. Korsmeyer ◽  
T. Knower ◽  
J.W. Covell
Keyword(s):  
Fork Length ◽  
Muscle Length ◽  
The Body ◽  
Emg Activity ◽  
Skipjack Tuna ◽  
Force Transmission ◽  
Muscle Strain ◽  
Muscle Shortening ◽  
Red Muscle ◽  
Length Changes

Cyclic length changes in the internal red muscle of skipjack tuna (Katsuwonus pelamis) were measured using sonomicrometry while the fish swam in a water tunnel at steady speeds of 1.1-2.3 L s(−)(1), where L is fork length. These data were coupled with simultaneous electromyographic (EMG) recordings. The onset of EMG activity occurred at virtually the same phase of the strain cycle for muscle at axial locations between approximately 0.4L and 0.74L, where the majority of the internal red muscle is located. Furthermore, EMG activity always began during muscle lengthening, 40–50 prior to peak length, suggesting that force enhancement by stretching and net positive work probably occur in red muscle all along the body. Our results support the idea that positive contractile power is derived from all the aerobic swimming muscle in tunas, while force transmission is provided primarily by connective tissue structures, such as skin and tendons, rather than by muscles performing negative work. We also compared measured muscle length changes with midline curvature (as a potential index of muscle strain) calculated from synchronised video image analysis. Unlike contraction of the superficial red muscle in other fish, the shortening of internal red muscle in skipjack tuna substantially lags behind changes in the local midline curvature. The temporal separation of red muscle shortening and local curvature is so pronounced that, in the mid-body region, muscle shortening at each location is synchronous with midline curvature at locations that are 7–8 cm (i.e. 8–10 vertebral segments) more posterior. These results suggest that contraction of the internal red muscle causes deformation of the body at more posterior locations, rather than locally. This situation represents a unique departure from the model of a homogeneous bending beam, which describes red muscle strain in other fish during steady swimming, but is consistent with the idea that tunas produce thrust by motion of the caudal fin rather than by undulation of segments along the body.

scholarly journals Effects of cross-bridge compliance on the force-velocity relationship and muscle power output

PLoS ONE ◽  
2017 ◽  
Vol 12 (12) ◽  
pp. e0190335 ◽  
Author(s):  
Axel J. Fenwick ◽  
Alexander M. Wood ◽  
Bertrand C. W. Tanner
Keyword(s):  
Power Output ◽  
Muscle Power ◽  
Cross Bridge ◽  
Velocity Relationship ◽  
Force Velocity ◽  
Muscle Power Output

Climbing Performance of Harris' Hawks (Parabuteo Unicinctus) with Added Load: Implications for Muscle Mechanics and for Radiotracking

1989 ◽  
Vol 142 (1) ◽  
pp. 17-29 ◽  
Author(s):  
C. J. PENNYCUICK ◽  
M. R. FULLER ◽  
LYNNE McALLISTER
Keyword(s):  
Body Mass ◽  
Power Output ◽  
Muscle Power ◽  
Muscle Mechanics ◽  
The Body ◽  
Power Product ◽  
Horizontal Flight ◽  
Flight Muscles ◽  
Food Load ◽  
Parabuteo Unicinctus

Two Harris' hawks were trained to fly along horizontal and climbing flight paths, while carrying loads of various masses, to provide data for estimating available muscle power during short flights. The body mass of both hawks was about 920 g, and they were able to carry loads up to 630 g in horizontal flight. The rate of climb decreased with increasing all-up mass, as also did the climbing power (product of weight and rate of climb). Various assumptions about the aerodynamic power in low-speed climbs led to estimates of the maximum power output of the flight muscles ranging from 41 to 46 W. This, in turn, would imply a stress during shortening of around 210 kPa. The effects of a radio package on a bird that is raising young should be considered in relation to the food load that the forager can normally carry, rather than in relation to its body mass.

Role of muscle power output as a mediator between gait variability and gait velocity in hospitalized older adults

2019 ◽  
Vol 124 ◽  
pp. 110631 ◽  
Author(s):  
Mikel L. Sáez de Asteasu ◽  
Nicolás Martínez-Velilla ◽  
Fabricio Zambom-Ferraresi ◽  
Álvaro Casas-Herrero ◽  
Robinson Ramirez-Vélez ◽  
...  
Keyword(s):  
Older Adults ◽  
Power Output ◽  
Muscle Power ◽  
Gait Variability ◽  
Gait Velocity ◽  
Hospitalized Older Adults ◽  
Muscle Power Output
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