scholarly journals Muscle power output during escape responses in an Antarctic fish

1997 ◽  
Vol 200 (4) ◽  
pp. 703-712 ◽  
Author(s):  
C E Franklin ◽  
I A Johnston
Keyword(s):  
Fibre Length ◽  
Antarctic Fish ◽  
Maximum Velocity ◽  
The Body ◽  
Muscle Performance ◽  
Muscle Fibres ◽  
Cycle Duration ◽  
Peak Strain ◽  
Escape Responses

Escape responses (C-shaped fast-starts) were filmed at 500 frames s-1 in the Antarctic rock cod (Notothenia coriiceps) at 0 °C. The activation and strain patterns of the superficial fast myotomal muscle were measured simultaneously using electromyography and sonomicrometry respectively. In order to bend the body into the initial C-shape, the muscle fibres in the rostral myotomes (at 0.35L, where L is total length) shortened by up to 13 % of their resting length at a maximum velocity of 1.68 fibre lengths s-1. During the contralateral contraction, muscle fibres were stretched (by 5 % and 7 % at 0.35L and 0.65L, respectively) and were activated prior to the end of lengthening, before shortening by up to 12 % of resting fibre length (peak-to-peak strain). Representative strain records were digitised to create cyclical events corresponding to the C-bend and contralateral contraction. Isolated fibres were subjected to the abstracted strain cycles and stimulated at the same point and for the same duration as occurs in vivo. During the early phase of shortening, muscle shortening velocity (V) increased dramatically whilst the load was relatively constant and represented a substantial fraction of the maximum isometric stress. Pre-stretch of active muscle was associated with significant force enhancement. For the contralateral contraction, V exceeded that predicted by the steady-state force­velocity relationship for considerable periods during each tailbeat, contributing to relatively high maximum instantaneous power outputs of up to 290 W kg-1 wet muscle mass. In vitro experiments, involving adjusting strain, cycle duration and stimulation parameters, indicated that in vivo muscle fibres produce close to their maximum power. During escape responses, the maximum velocity and acceleration recorded from the centre of gravity of the fish were 0.71±0.03 m s-1 and 17.1±1.4 m s-2, respectively (mean ± s.e.m., N=7 fish). Muscle performance was sufficient to produce maximum velocities and accelerations that were within the lower end of the range reported for temperate-zone fish.

scholarly journals How muscles deal with real-world loads: the influence of length trajectory on muscle performance

1999 ◽  
Vol 202 (23) ◽  
pp. 3377-3385 ◽  
Author(s):  
R.L. Marsh
Keyword(s):  
Velocity Profile ◽  
Real World ◽  
Skeletal Muscles ◽  
External Environment ◽  
The Body ◽  
Muscle Performance ◽  
Force Output ◽  
Optimal Velocity ◽  
Level Running

The performance of skeletal muscles in vivo is determined by the feedback received when the muscle interacts with the external environment via various morphological structures. This interaction between the muscle and the ‘real-world load’ forces us to reconsider how muscles are adapted to suit their in vivo function. We must consider the co-evolution of the muscles and the morphological structures that ‘create’ the load in concert with the properties of the external environment. This complex set of interactions may limit muscle performance acutely and may also constrain the evolution of morphology and physiology. The performance of skeletal muscle is determined by the length trajectory during movement and the pattern of stimulation. Important features of the length trajectory include its amplitude, frequency, starting length and shape (velocity profile). Many of these parameters interact. For example, changing the velocity profile during shortening may change the optimum values of the other parameters. The length trajectory that maximizes performance depends on the task to be performed. During cyclical work, muscles benefit from using asymmetric cycles with longer shortening than lengthening phases. Modifying this ‘sawtooth’ cycle by increasing the velocity during shortening may further increase power by augmenting force output and speeding deactivation. In contrast, when accelerating an inertial load, as in jumping, the predicted ‘optimal’ velocity profile has two peak values, one early and one late in shortening. During level running at constant speed, muscles perform tasks other than producing work and power. Producing force to support the body weight is performed with nearly isometric contractions in some of the limb muscles of vertebrates. Muscles also play a key role in producing stability during running, and the intrinsic properties of the musculoskeletal system may be particularly important in stabilizing rapid running. Recently, muscles in running invertebrates and vertebrates have been described that routinely absorb large amounts of work during running. These muscles are hypothesized to play a key role in stability.

scholarly journals Mechanical properties of the myotomal musculo-skeletal system of rainbow trout, Salmo gairdneri

1985 ◽  
Vol 119 (1) ◽  
pp. 71-83 ◽  
Author(s):  
C. L. Johnsrude ◽  
P. W. Webb
Keyword(s):  
Maximum Velocity ◽  
The Body ◽  
Salmo Gairdneri ◽  
Maximum Speed ◽  
Muscle Fibres ◽  
Force Transmission ◽  
Muscle System ◽  
Cross Sectional ◽  
Mechanical Power Output ◽  
Fast Start

Net forces and velocities resulting from in situ contractions of the myotomal musculature on one side of the body were measured at the hypural bones. Forces, velocities and power were determined with the body bent into a range of postures typical of those observed during fast-start swimming. For trout averaging 0.178 m in length and 0.0605 kg in body mass, the muscle system exerts a maximum normal force of 2.2N at the base of the caudal fin. This force is equivalent to 11.8 kN m-2 based on the mean cross-sectional area of the myotomal muscle. The maximum velocity was 1.11 m s-1, and the maximum mechanical power output, 0.64 W, or 42.4 W kg-1 muscle. Based on estimates of swimming resistance, these results would suggest acceleration rates of 7.5 to 16.5 m s-2, similar to averages observed during fast-starts. Maximum sprint speeds would range from 6.5 to 17.8 body lengths s-1, spanning the range of maximum speeds reported in the literature. It is suggested that maximum speed is limited by interactions between muscle contraction frequency and endurance. Losses in the mechanical linkages between muscle fibres and propulsive surfaces were estimated at about 50% for power with possibly greater losses in force transmission. Maximum force and power did not vary over the range of postures tested, supporting Alexander's (1969) suggestions that white muscle should contract over a small portion of the resting length of the fibres.

scholarly journals Mechanical properties of red and white swimming muscles as a function of the position along the body of the eelAnguilla anguilla

2001 ◽  
Vol 204 (13) ◽  
pp. 2221-2230 ◽  
Author(s):  
K. D’Août ◽  
N. A. Curtin ◽  
T. L. Williams ◽  
P. Aerts
Keyword(s):  
Mechanical Properties ◽  
Body Length ◽  
Isometric Force ◽  
The Body ◽  
In Vivo Studies ◽  
Muscle Fibres ◽  
Entire Body ◽  
Work Output ◽  
Longitudinal Position

SUMMARYThe way in which muscles power steady swimming depends on a number of factors, including fibre type and recruitment, muscle strain, stimulation pattern and intensity, and the intrinsic mechanical properties of the muscle fibres. For a number of undulatory swimming fish species, in vivo studies have shown that muscles at different positions along the body are stimulated during different phases of the strain cycle. Moreover, some intrinsic contractile properties of the muscles have been found to vary according to their position along the body.We report the first results on the mechanical properties of the red and white muscles of an anguilliform swimmer, Anguilla anguilla. Small preparations (0.147–1.335mg dry mass) were dissected from positions at fractions of 0.2, 0.4, 0.6 and 0.8 of total body length (BL). We determined the time to 50% and 100% peak force and from the last stimulus to 50% relaxation for isometric contractions; we measured the sarcomere lengths that coincided with in situ resting length. None of these quantities varied significantly with the longitudinal position from which the fibres were taken. We also measured power and work output during contractions under conditions approximating those used in vivo (cycle frequency, 1Hz; strain amplitude, ±10%L0, where L0 is the length giving maximum isometric force). During these experiments, work output was affected by stimulation phase, but did not depend on the longitudinal position in the body from which the muscles were taken.Our results indicate that red and white eel muscles have uniform properties along the body. In this respect, they differ from the muscle of most non-anguilliforms, in which muscle kinetics varies in a systematic way along the body. Uniform properties may be beneficial for anguilliform swimmers, in which the amplitude of the travelling wave can be pronounced over the entire body length.

MYOTOMAL MUSCLE FUNCTION AT DIFFERENT LOCATIONS IN THE BODY OF A SWIMMING FISH

1993 ◽  
Vol 182 (1) ◽  
pp. 191-206 ◽  
Author(s):  
J. D. Altringham ◽  
C. S. Wardle ◽  
C. I. Smith
Keyword(s):  
Power Output ◽  
Muscle Function ◽  
Muscle Activation ◽  
Muscle Power ◽  
Travelling Waves ◽  
The Body ◽  
Muscle Fibres ◽  
Cycle Frequency ◽  
Lateral Muscle

We describe experiments on isolated, live muscle fibres which simulate their in vivo activity in a swimming saithe (Pollachius virens). Superficial fast muscle fibres isolated from points 0.35, 0.5 and 0.65 body lengths (BL) from the anterior tip had different contractile properties. Twitch contraction time increased from rostral to caudal myotomes and power output (measured by the work loop technique) decreased. Power versus cycle frequency curves of rostral fibres were shifted to higher frequencies relative to those of caudal fibres. In the fish, phase differences between caudally travelling waves of muscle activation and fish bending suggest a change in muscle function along the body. In vitro experiments indicate that in vivo superficial fast fibres of rostral myotomes are operating under conditions that yield maximum power output. Caudal myotomes are active as they are lengthened in vivo and initially operate under conditions which maximise their stiffness, before entering a positive power-generating phase. A description is presented for the generation of thrust at the tail blade by the superficial, fast, lateral muscle. Power generated rostrally is transmitted to the tail by stiffened muscle placed more caudally. A transition zone between power generation and stiffening travels caudally, and all but the most caudal myotomes generate power at some phase of the tailbeat. Rostral power output, caudal force, bending moment and force at the tail blade are all maximal at essentially the same moment in the tailbeat cycle, as the tail blade crosses the swimming track.

The musculature of Peripatus and its innervation

1980 ◽  
Vol 288 (1031) ◽  
pp. 481-510 ◽  
Keyword(s):  
Body Wall ◽  
Fibre Length ◽  
Gross Anatomy ◽  
Small Degree ◽  
The Body ◽  
Muscle Fibres ◽  
Neuromuscular Synapses ◽  
Thick Filaments ◽  
Small Muscle ◽  
Tubule Diameter

The musculature of the Onychophoran Peripatus dominicae , its ultrastructure and details of innervation are described. Significant differences were noted between its gross anatomy and that reported in previous accounts, notably in the presence of inner circular body wall muscle and a prominent, functionally significant, levator of the leg. The former is important in regard to the evolutionary position of the Onychophora while the latter helps us to understand the control of walking in a lobopodial leg, and therefore the evolution of arthropod locomotion, which was the focus of our interest. Individual muscle fibres are either directly or indirectly attached to the body wall by collagen. There is a small degree of branching of fibres, with or without anastomosis, near their insertions, but most are as long as the muscle of which they are part, and are unbranched except for an occasional thin arm, emerging at an angle, that becomes invaded by collagen fibres and inserts in the skin. Diameters of muscle fibres vary from 1 to 45 pm. They are invaginated by two separate systems of unique wide (0.3 pm) tubules, longitudinal and radial. These are lined with similar material to that forming the basement material of the sarcolemma, and also contain fine strands with collagen-type cross-banding that connect to collagen bundles outside the fibres. In addition there are narrow tubules of ordinary T-tubule diameter. Both wide and narrow tubules make contacts with sarcoplasmic reticulum cysternae. Dense Z bodies are attached to both kinds of wide tubule, to the inside of the sarcolemma, and are scattered, without any obvious array, in the sarcoplasm. Thin myofilaments emerge from the Z bodies parallel to the fibre axis. Thick filaments occur in clusters with a loosely hexagonal array, but without any regular relation to thin ones: relatively few orbits of thin around thick filaments were seen in many muscle fibres regardless of fibre length and conditions during fixation. A unique innervation pattern was found, consisting of a combination of muscle arm to nerve contacts, which appear to be the commonest, and nerve on muscle fibre synapses. At least 13 motor axons were found to supply each small muscle or cluster of muscle fibres in a large muscle. Each muscle arm simultaneously makes synaptic contact with 3 to 7 axons. Nerve on muscle junctions contain from 1 to 8 axons, each making synaptic contacts. The details of the postsynaptic endplate-specializations resemble those seen in mammalian endplates and are markedly different from both arthropod and annelidan neuromuscular synapses.

scholarly journals Computational modelling of muscle fibre operating ranges in the hindlimb of a small ground bird (Eudromia elegans), with implications for modelling locomotion in extinct species

2021 ◽  
Vol 17 (4) ◽  
pp. e1008843
Author(s):  
Peter J. Bishop ◽  
Krijn B. Michel ◽  
Antoine Falisse ◽  
Andrew R. Cuff ◽  
Vivian R. Allen ◽  
...  
Keyword(s):  
Muscle Function ◽  
Computational Models ◽  
Fibre Length ◽  
Computational Modelling ◽  
Length Change ◽  
Muscle Fibres ◽  
Extinct Species ◽  
Length Changes ◽  
Experimental Findings

The arrangement and physiology of muscle fibres can strongly influence musculoskeletal function and whole-organismal performance. However, experimental investigation of muscle function during in vivo activity is typically limited to relatively few muscles in a given system. Computational models and simulations of the musculoskeletal system can partly overcome these limitations, by exploring the dynamics of muscles, tendons and other tissues in a robust and quantitative fashion. Here, a high-fidelity, 26-degree-of-freedom musculoskeletal model was developed of the hindlimb of a small ground bird, the elegant-crested tinamou (Eudromia elegans, ~550 g), including all the major muscles of the limb (36 actuators per leg). The model was integrated with biplanar fluoroscopy (XROMM) and forceplate data for walking and running, where dynamic optimization was used to estimate muscle excitations and fibre length changes throughout both gaits. Following this, a series of static simulations over the total range of physiological limb postures were performed, to circumscribe the bounds of possible variation in fibre length. During gait, fibre lengths for all muscles remained between 0.5 to 1.21 times optimal fibre length, but operated mostly on the ascending limb and plateau of the active force-length curve, a result that parallels previous experimental findings for birds, humans and other species. However, the ranges of fibre length varied considerably among individual muscles, especially when considered across the total possible range of joint excursion. Net length change of muscle–tendon units was mostly less than optimal fibre length, sometimes markedly so, suggesting that approaches that use muscle–tendon length change to estimate optimal fibre length in extinct species are likely underestimating this important parameter for many muscles. The results of this study clarify and broaden understanding of muscle function in extant animals, and can help refine approaches used to study extinct species.

Power at the expense of efficiency in contraction of white muscle fibres from dogfish Scyliorhinus canicula

1996 ◽  
Vol 199 (3) ◽  
pp. 593-601 ◽  
Author(s):  
N Curtin ◽  
R Woledge
Keyword(s):  
Duty Cycle ◽  
White Muscle ◽  
Fibre Length ◽  
Energy Output ◽  
Muscle Fibres ◽  
Cycle Duration ◽  
Scyliorhinus Canicula ◽  
Stimulus Timing ◽  
High Level ◽  
Myotomal Muscle

Work and heat production of white myotomal muscle fibres from dogfish were measured during sinusoidal movement (0.71-5.0 Hz) at 12 C. Stimulus phase (stimulus timing relative to movement) and duty cycle (stimulus duration as a fraction of movement cycle duration) were varied to determine the parameters optimal for power output and for efficiency (work/total energy output). Movements of 0.067 and 0.120L0 were used, where L0 is the muscle fibre length giving maximum force in an isometric tetanus. At each frequency of movement and duty cycle, the stimulus phase giving the highest power was the same as that giving the highest efficiency. In contrast, at each frequency and optimal stimulus phase, the dependence of power on duty cycle was very different from the dependence of efficiency on duty cycle. Power generally increased with increasing duty cycle, whereas efficiency decreased. Thus, high power can be achieved at the expense of efficiency by adjusting stimulus duty cycle. When stimulus phase and duty cycle were optimized, efficiency was always higher for the larger distance of movement. The efficiency of energy conversion can be maintained at a high level as the frequency of movement increases from 1.25 to 5.0 Hz.

Energetics and power output of isolated fish fast muscle fibres performing oscillatory work

1991 ◽  
Vol 158 (1) ◽  
pp. 261-273 ◽  
Author(s):  
T. W. Moon ◽  
J. D. Altringham ◽  
I. A. Johnston
Keyword(s):  
High Performance ◽  
Energy Charge ◽  
Fibre Length ◽  
Creatine Phosphate ◽  
High Energy ◽  
Rapid Decline ◽  
Muscle Fibres ◽  
Tight Coupling ◽  
Work Cycle

Fast myotomal muscle fibres were isolated from the cod (Gadus morhua L.) and the energy cost of contraction was measured under conditions simulating swimming. Fibre bundles were subjected to sinusoidal cycles of shortening and lengthening about their in situ fibre length, and stimulated at selected phases in each cycle. The preparations were poisoned with iodoacetic acid and bubbled with nitrogen to block the synthesis of ATP. After an initial rapid decline over the first 10 cycles, force and net work remained steady in some cases for up to 64 oscillatory length cycles, but more commonly declined slowly after about 30 cycles. The total mechanical work performed increased largely in proportion to the number of work cycles. At the end of each experiment fibres were frozen in isopentane cooled in liquid nitrogen and metabolite concentrations determined by high performance liquid chromatography (HPLC) and enzymatic analysis. Concentrations of adenylates did not differ significantly from control values, although a significant increase in IMP concentrations at 64 cycles accounted for the maintenance of relatively high energy charge values. Creatine (C) concentrations increased and creatine phosphate (CP) concentrations decreased, implying a tight coupling of the ATP/ADP reaction to the CP/C reaction. Muscle economy was calculated as the positive work performed during a work cycle divided by the total chemical energy expended. These values (approx. 7 mJ mumol-1) were found to be independent of the number of work cycles performed, although a trend to increase was observed. Muscle efficiency values, calculated assuming a Gibb's force free energy change for CP splitting in vivo of 55 kJ mol-1, were in the range 12–23%.

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.

The Role of Polyphenols in the Modulation of Plasma Non-Enzymatic Antioxidant Capacity (NEAC)

2012 ◽  
Vol 82 (3) ◽  
pp. 228-232 ◽  
Author(s):  
Mauro Serafini ◽  
Giuseppa Morabito
Keyword(s):  
Antioxidant Capacity ◽  
Dietary Intervention ◽  
Ex Vivo ◽  
The Body ◽  
Dietary Polyphenols ◽  
Enzymatic Antioxidant ◽  
Endogenous Antioxidant

Dietary polyphenols have been shown to scavenge free radicals, modulating cellular redox transcription factors in different in vitro and ex vivo models. Dietary intervention studies have shown that consumption of plant foods modulates plasma Non-Enzymatic Antioxidant Capacity (NEAC), a biomarker of the endogenous antioxidant network, in human subjects. However, the identification of the molecules responsible for this effect are yet to be obtained and evidences of an antioxidant in vivo action of polyphenols are conflicting. There is a clear discrepancy between polyphenols (PP) concentration in body fluids and the extent of increase of plasma NEAC. The low degree of absorption and the extensive metabolism of PP within the body have raised questions about their contribution to the endogenous antioxidant network. This work will discuss the role of polyphenols from galenic preparation, food extracts, and selected dietary sources as modulators of plasma NEAC in humans.

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