scholarly journals Muscle power output limits fast-start performance in fish.

1998 ◽  
Vol 201 (10) ◽  
pp. 1505-1526 ◽  
Author(s):  
J M Wakeling ◽  
I A Johnston
Keyword(s):  
Muscle Mass ◽  
Power Output ◽  
White Muscle ◽  
Muscle Power ◽  
Specific Power ◽  
Muscle Dynamics ◽  
Power Outputs ◽  
Work Loop ◽  
Muscle Power Output

Fast-starts associated with escape responses were filmed at the median habitat temperatures of six teleost fish: Notothenia coriiceps and Notothenia rossii (Antarctica), Myoxocephalus scorpius (North Sea), Scorpaena notata and Serranus cabrilla (Mediterranean) and Paracirrhites forsteri (Indo-West-Pacific Ocean). Methods are presented for estimating the spine positions for silhouettes of swimming fish. These methods were used to validate techniques for calculating kinematics and muscle dynamics during fast-starts. The starts from all species show common patterns, with waves of body curvature travelling from head to tail and increasing in amplitude. Cross-validation with sonomicrometry studies allowed gearing ratios between the red and white muscle to be calculated. Gearing ratios must decrease towards the tail with a corresponding change in muscle geometry, resulting in similar white muscle fibre strains in all the myotomes during the start. A work-loop technique was used to measure mean muscle power output at similar strain and shortening durations to those found in vivo. The fast Sc. notata myotomal fibres produced a mean muscle-mass-specific power of 142.7 W kg-1 at 20 degrees C. Velocity, acceleration and hydrodynamic power output increased both with the travelling rate of the wave of body curvature and with the habitat temperature. At all temperatures, the predicted mean muscle-mass-specific power outputs, as calculated from swimming sequences, were similar to the muscle power outputs measured from work-loop experiments.

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.

scholarly journals The influence of temperature on power production during swimming. II. Mechanics of red muscle fibres in vivo

2000 ◽  
Vol 203 (2) ◽  
pp. 333-345 ◽  
Author(s):  
L.C. Rome ◽  
D.M. Swank ◽  
D.J. Coughlin
Keyword(s):  
Power Output ◽  
Muscle Power ◽  
Muscle Performance ◽  
Muscle Fibres ◽  
Relaxation Rates ◽  
Red Muscle ◽  
The Impact ◽  
Positive Work ◽  
Muscle Power Output

We found previously that scup (Stenotomus chrysops) reduce neither their stimulation duration nor their tail-beat frequency to compensate for the slow relaxation rates of their muscles at low swimming temperatures. To assess the impact of this ‘lack of compensation’ on power generation during swimming, we drove red muscle bundles under their in vivo conditions and measured the resulting power output. Although these in vivo conditions were near the optimal conditions for much of the muscle at 20 degrees C, they were far from optimal at 10 degrees C. Accordingly, in vivo power output was extremely low at 10 degrees C. Although at 30 cm s(−)(1), muscles from all regions of the fish generated positive work, at 40 and 50 cm s(−)(1), only the POST region (70 % total length) generated positive work, and that level was low. This led to a Q(10) of 4–14 in the POST region (depending on swimming speed), and extremely high or indeterminate Q(10) values (if power at 10 degrees C is zero or negative, Q(10) is indeterminate) for the other regions while swimming at 40 or 50 cm s(−)(1). To assess whether errors in measurement of the in vivo conditions could cause artificially reduced power measurements at 10 degrees C, we drove muscle bundles through a series of conditions in which the stimulation duration was shortened and other parameters were made closer to optimal. This sensitivity analysis revealed that the low power output could not be explained by realistic levels of systematic or random error. By integrating the muscle power output over the fish's mass and comparing it with power requirements for swimming, we conclude that, although the fish could swim at 30 cm s(−)(1) with the red muscle alone, it is very unlikely that it could do so at 40 and 50 cm s(−)(1), thus raising the question of how the fish powers swimming at these speeds. By integrating in vivo pink muscle power output along the length of the fish, we obtained the surprising finding that, at 50 cm s(−)(1), the pink muscle (despite having one-third the mass) contributes six times more power to swimming than does the red muscle. Thus, in scup, pink muscle is crucial for powering swimming at low temperatures. This overall analysis shows that Q(10) values determined in experiments on isolated tissue under arbitrarily selected conditions can be very different from Q(10) values in vivo, and therefore that predicting whole-animal performance from these isolated tissue experiments may lead to qualitatively incorrect conclusions. To make a meaningful assessment of the effects of temperature on muscle and locomotory performance, muscle performance must be studied under the conditions at which the muscle operates in vivo.

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

PECTORALIS MUSCLE FORCE AND POWER OUTPUT DURING DIFFERENT MODES OF FLIGHT IN PIGEONS (COLUMBA LIVIA)

1993 ◽  
Vol 176 (1) ◽  
pp. 31-54 ◽  
Author(s):  
K. P. Dial ◽  
A. A. Biewener
Keyword(s):  
Strain Gauge ◽  
Power Output ◽  
Muscle Force ◽  
Columba Livia ◽  
Principal Strain ◽  
Specific Power ◽  
Single Element ◽  
Pectoralis Muscle ◽  
Level Flight

In vivo measurements of pectoralis muscle force during different modes of free flight (takeoff, level flapping, landing, vertical ascending and near vertical descending flight) were obtained using a strain gauge attached to the dorsal surface of the delto-pectoral crest (DPC) of the humerus in four trained pigeons (Columba livia). In one bird, a rosette strain gauge was attached to the DPC to determine the principal axis of strain produced by tension of the pectoralis. Strain signals recorded during flight were calibrated to force based on in situ measurements of tetanic force and on direct tension applied to the muscle's insertion at the DPC. Rosette strain recordings showed that at maximal force the orientation of tensile principal strain was −15° (proximo-anterior) to the perpendicular axis of the DPC (or +75° to the longitudinal axis of the humerus), ranging from +15 to −25° to the DPC axis during the downstroke. The consistency of tensile principal strain orientation in the DPC confirms the more general use of single-element strain gauges as being a reliable method for determining in vivo pectoralis force generation. Our strain recordings show that the pectoralis begins to develop force as it is being lengthened, during the final one-third of the upstroke, and attains maximum force output while shortening during the first one-third of the downstroke. Force is sustained throughout the entire downstroke, even after the onset of the upstroke for certain flight conditions. Mean peak forces developed by the pectoralis based on measurements from 40 wingbeats for each bird (160 total) were: 24.9+/−3.1 N during takeoff, 19.7+/−2.0 N during level flight (at speeds of about 6–9 m s-1 and a wingbeat frequency of 8.6+/−0.3 Hz), 18.7+/−2.5 N during landing, 23.7+/−2.7 N during near-vertical descent, and 26.0+/−1.8 N during vertical ascending flight. These forces are considerably lower than the maximum isometric force (67 N, P0) of the muscle, ranging from 28 % (landing) to 39 % (vertical ascending) of P0. Based on estimates of muscle fiber length change determined from high- speed (200 frames s-1) light cine films taken of the animals, we calculate the mass-specific power output of the pigeon pectoralis to be 51 W kg-1 during level flight (approximately 8 m s-1), and 119 W kg-1 during takeoff from the ground. When the birds were harnessed with weighted backpacks (50 % and 100 % of body weight), the forces generated by the pectoralis did not significantly exceed those observed in unloaded birds executing vertical ascending flight. These data suggest that the range of force production by the pectoralis under these differing conditions is constrained by the force- velocity properties of the muscle operating at fairly rapid rates of shortening (4.4 fiber lengths s-1 during level flight and 6.7 fiber lengths s-1 during takeoff).

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

scholarly journals The weak link: do muscle properties determine locomotor performance in frogs?

2011 ◽  
Vol 366 (1570) ◽  
pp. 1488-1495 ◽  
Author(s):  
Thomas J. Roberts ◽  
Emily M. Abbott ◽  
Emanuel Azizi
Keyword(s):  
Muscle Mass ◽  
Power Output ◽  
Muscle Power ◽  
Locomotor Performance ◽  
Jump Performance ◽  
Leopard Frogs ◽  
Ideal System ◽  
Mechanical Power Output ◽  
Osteopilus Septentrionalis ◽  
Jump Power

Muscles power movement, yet the conceptual link between muscle performance and locomotor performance is poorly developed. Frog jumping provides an ideal system to probe the relationship between muscle capacity and locomotor performance, because a jump is a single discrete event and mechanical power output is a critical determinant of jump distance. We tested the hypothesis that interspecific variation in jump performance could be explained by variability in available muscle power. We used force plate ergometry to measure power produced during jumping in Cuban tree frogs ( Osteopilus septentrionalis ), leopard frogs ( Rana pipiens ) and cane toads ( Bufo marinus ). We also measured peak isotonic power output in isolated plantaris muscles for each species. As expected, jump performance varied widely. Osteopilus septentrionalis developed peak power outputs of 1047.0 ± 119.7 W kg −1 hindlimb muscle mass, about five times that of B. marinus (198.5 ± 54.5 W kg −1 ). Values for R. pipiens were intermediate (543.9 ± 96.2 W kg −1 ). These differences in jump power were not matched by differences in available muscle power, which were 312.7 ± 28.9, 321.8 ± 48.5 and 262.8 ± 23.2 W kg −1 muscle mass for O. septentrionalis , R. pipiens and B. marinus , respectively. The lack of correlation between available muscle power and jump power suggests that non-muscular mechanisms (e.g. elastic energy storage) can obscure the link between muscle mechanical performance and locomotor performance.

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