scholarly journals The influence of temperature on power output of scup red muscle during cyclical length changes

1992 ◽  
Vol 171 (1) ◽  
pp. 261-281 ◽  
Author(s):  
L. C. Rome ◽  
D. Swank
Keyword(s):  
Power Output ◽  
Oscillation Frequency ◽  
Maximum Power ◽  
Red Muscle ◽  
Influence Of Temperature On ◽  
Simple Extrapolation ◽  
Length Changes ◽  
Oscillation Frequencies ◽  
Work Loop

To gain insight into how temperature affects locomotory performance, we measured power output of scup red muscle during oscillatory length changes at 10 degrees C and 20 degrees C. When we optimized work loop parameters, we found that maximum power was 27.9 W kg-1 at 20 degrees C and 12.8 W kg-1 at 10 degrees C, giving a Q10 of 2.29. Maximum power was generated at a higher oscillation frequency at 20 degrees C (5 Hz) than at 10 degrees C (2.5 Hz), and the Q10 for power output at a given oscillation frequency ranged from about 1 at 1 Hz to about 5 at 7.5 Hz. An analysis of the results in terms of crossbridge kinetics suggests that the higher power output at 20 degrees C is associated with both a higher Vmax (i.e. more power per cycling crossbridge) and faster activation and relaxation (i.e. a greater number of cycling crossbridges). To obtain a more realistic understanding of the functional importance of temperature effects on muscle, we imposed on isolated muscle in vivo length changes and oscillation frequencies (measured during previous experiments on swimming scup) and the in vivo stimulus duty cycle (measured from electromyograms in this study). At 20 degrees C, muscle bundles tested under these in vivo conditions produced nearly maximal power, suggesting that the muscle works optimally during locomotion and, thus, important contractile parameters have been adjusted to produce maximum mechanical power at the oscillation frequencies and length changes needed during swimming. At 10 degrees C, muscle bundles tested under in vivo conditions produced much less power than was obtained during the ‘optimized’ work loop experiments discussed above. Furthermore, although ‘optimized’ work loop experiments showed that maximum power output occurs at 2.5 Hz, scup do not appear to swim with such a low tailbeat frequency. Although the reason for these apparent discrepancies at 10 degrees C are not known, it shows that simple extrapolation from isolated muscle to the whole animal, without knowledge of how the muscle is actually used in vivo, can be misleading.

Muscle length changes during swimming in scup: sonomicrometry verifies the anatomical high-speed cine technique.

1996 ◽  
Vol 199 (2) ◽  
pp. 459-463 ◽  
Author(s):  
D J Coughlin ◽  
L Valdes ◽  
L C Rome
Keyword(s):  
High Speed ◽  
Muscle Length ◽  
Fish Muscles ◽  
Muscle Shortening ◽  
Red Muscle ◽  
Independent Technique ◽  
Loop Technique ◽  
Length Changes ◽  
Work Loop

Recent attempts to determine how fish muscles are used to power swimming have employed the work loop technique (driving isolated muscles using their in vivo strain and stimulation pattern). These muscle strains have in turn been determined from the anatomical high-speed cine technique. In this study, we used an independent technique, sonomicrometry, to attempt to verify these strain measurements and the conclusions based on them. We found that the strain records measured from sonomicrometry and the anatomical-cine techniques were very similar. The ratio of the strain measured from sonomicrometry to that from the anatomical-cine technique was remarkably close to unity (1.046 +/- 0.013, mean +/- S.E.M., N = 15, for transducers placed on the muscle surface and corrected for muscle depth, and 0.921 +/- 0.028, N = 8, in cases where the transducers were inserted to the average depth of the red muscle). These measurements also showed that red muscle shortening occurs simultaneously with local backbone curvature, unlike previous results which suggested that white muscle shortening during the escape response occurs prior to the change in local backbone curvature.

scholarly journals Scaling of Power Output in Fast Muscle Fibres of the Atlantic Cod During Cyclical Contractions

1992 ◽  
Vol 170 (1) ◽  
pp. 143-154 ◽  
Author(s):  
M. ELIZABETH ANDERSON ◽  
IAN A. JOHNSTON
Keyword(s):  
Steady State ◽  
Power Output ◽  
Standard Length ◽  
Atlantic Cod ◽  
Maximum Power ◽  
Fast Muscle ◽  
Muscle Fibres ◽  
Cycle Frequency ◽  
Maximum Power Output ◽  
Length Changes

Fast muscle fibres were isolated from abdominal myotomes of Atlantic cod (Gadus morhua L.) ranging in size from 10 to 63 cm standard length (Ls). Muscle fibres were subjected to sinusoidal length changes about their resting length (Lf) and stimulated at a selected phase of the strain cycle. The work performed in each oscillatory cycle was calculated from plots of force against muscle length, the area of the resulting loop being net work. Strain and the number and timing of stimuli were adjusted to maximise positive work per cycle over a range of cycle frequencies at 8°C. Force, and hence power output, declined with increasing cycles of oscillation until reaching a steady state around the ninth cycle. The strain required for maximum power output (Wmax) was ±7-11% of Lf in fish shorter than 18 cm standard length, but decreased to ±5 % of Lf in larger fish. The cycle frequency required for Wmax also declined with increasing fish length, scaling to Ls−0.51 under steady-state conditions (cycles 9–12). At the optimum cycle frequency and strain the maximum contraction velocity scaled to Ls−0.79. The maximum stress (Pmax) produced within a cycle was highest in the second cycle, ranging from 51.3 kPa in 10 cm fish to 81.8 kPa in 60 cm fish (Pmax=28.2Ls0.25). Under steady-state conditions the maximum power output per kilogram wet muscle mass was found to range from 27.5 W in a 10 cm Ls cod to 16.4 W in a 60 cm Ls cod, scaling with Ls−0.29 and body mass (Mb)−0.10 Note: To whom reprint requests should be sent

Effects of longitudinal body position and swimming speed on mechanical power of deep red muscle from skipjack tuna (Katsuwonus pelamis)

2002 ◽  
Vol 205 (2) ◽  
pp. 189-200
Author(s):  
Douglas A. Syme ◽  
Robert E. Shadwick
Keyword(s):  
Swimming Speed ◽  
Power Output ◽  
Beat Frequency ◽  
Mechanical Power ◽  
Skipjack Tuna ◽  
Cycle Frequency ◽  
Katsuwonus Pelamis ◽  
Red Muscle ◽  
Tail Beat ◽  
Work Loop

SUMMARY The mechanical power output of deep, red muscle from skipjack tuna (Katsuwonus pelamis) was studied to investigate (i) whether this muscle generates maximum power during cruise swimming, (ii) how the differences in strain experienced by red muscle at different axial body locations affect its performance and (iii) how swimming speed affects muscle work and power output. Red muscle was isolated from approximately mid-way through the deep wedge that lies next to the backbone; anterior (0.44 fork lengths, ANT) and posterior (0.70 fork lengths, POST) samples were studied. Work and power were measured at 25°C using the work loop technique. Stimulus phases and durations and muscle strains (±5.5 % in ANT and ±8 % in POST locations) experienced during cruise swimming at different speeds were obtained from previous studies and used during work loop recordings. In addition, stimulus conditions that maximized work were determined. The stimulus durations and phases yielding maximum work decreased with increasing cycle frequency (analogous to tail-beat frequency), were the same at both axial locations and were almost identical to those used by the fish during swimming, indicating that the muscle produces near-maximal work under most conditions in swimming fish. While muscle in the posterior region undergoes larger strain and thus produces more mass-specific power than muscle in the anterior region, when the longitudinal distribution of red muscle mass is considered, the anterior muscles appear to contribute approximately 40 % more total power. Mechanical work per length cycle was maximal at a cycle frequency of 2–3 Hz, dropping to near zero at 15 Hz and by 20–50 % at 1 Hz. Mechanical power was maximal at a cycle frequency of 5 Hz, dropping to near zero at 15 Hz. These fish typically cruise with tail-beat frequencies of 2.8–5.2 Hz, frequencies at which power from cyclic contractions of deep red muscles was 75–100 % maximal. At any given frequency over this range, power using stimulation conditions recorded from swimming fish averaged 93.4±1.65 % at ANT locations and 88.6±2.08 % at POST locations (means ± s.e.m., N=3–6) of the maximum using optimized conditions. When cycle frequency was held constant (4 Hz) and strain amplitude was increased, work and power increased similarly in muscles from both sample sites; work and power increased 2.5-fold when strain was elevated from ±2 to ±5.5 %, but increased by only approximately 12 % when strain was raised further from ±5.5 to ±8 %. Taken together, these data suggest that red muscle fibres along the entire body are used in a similar fashion to produce near-maximal mechanical power for propulsion during normal cruise swimming. Modelling suggests that the tail-beat frequency at which power is maximal (5 Hz) is very close to that used at the predicted maximum aerobic swimming speed (5.8 Hz) in these fish.

The effects of adrenaline on the work- and power-generating capacity of rat papillary muscle in vitro.

1997 ◽  
Vol 200 (3) ◽  
pp. 503-509
Author(s):  
J Layland ◽  
I S Young ◽  
J D Altringham
Keyword(s):  
Cardiac Muscle ◽  
Power Output ◽  
Maximum Power ◽  
Maximum Power Output ◽  
Generating Capacity ◽  
Loop Technique ◽  
Maximum Work ◽  
Frequency Relationship ◽  
Work Loop

The work loop technique was used to examine the effects of adrenaline on the mechanics of cardiac muscle contraction in vitro. The length for maximum active force (Lmax) and net work production (Lopt) for rat papillary muscles was determined under control conditions (without adrenaline). The concentration of adrenaline producing the maximum inotropic effect was determined. This concentration was used in the remainder of the experiments. Sinusoidal strain cycles about Lopt were performed over a physiologically relevant range of cycle frequencies (4-11 Hz). Maximum work and the frequency for maximum work increased from 1.91 J kg-1 at 3 Hz in controls to 2.97 J kg-1 at 6 Hz with adrenaline. Similarly, maximum power output and the frequency for maximum power output (fopt) increased from 8.62 W kg-1 at 6 Hz in controls to 19.95 W kg-1 at 8 Hz with adrenaline. We suggest that the power-frequency relationship, derived using the work loop technique, represents a useful index with which to assess the effects of pharmacological interventions on cardiac muscle contractility.

Early effects of ageing on the mechanical performance of isolated locomotory (EDL) and respiratory (diaphragm) skeletal muscle using the work-loop technique

2014 ◽  
Vol 307 (6) ◽  
pp. R670-R684 ◽  
Author(s):  
Jason Tallis ◽  
Rob S. James ◽  
Alexander G. Little ◽  
Val M. Cox ◽  
Michael J. Duncan ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Power Output ◽  
Muscle Performance ◽  
Maximal Power ◽  
Maximal Power Output ◽  
Age Related ◽  
Loop Technique ◽  
Edl Muscle ◽  
Work Loop

Previous isolated muscle studies examining the effects of ageing on contractility have used isometric protocols, which have been shown to have poor relevance to dynamic muscle performance in vivo. The present study uniquely uses the work-loop technique for a more realistic estimation of in vivo muscle function to examine changes in mammalian skeletal muscle mechanical properties with age. Measurements of maximal isometric stress, activation and relaxation time, maximal power output, and sustained power output during repetitive activation and recovery are compared in locomotory extensor digitorum longus (EDL) and core diaphragm muscle isolated from 3-, 10-, 30-, and 50-wk-old female mice to examine the early onset of ageing. A progressive age-related reduction in maximal isometric stress that was of greater magnitude than the decrease in maximal power output occurred in both muscles. Maximal force and power developed earlier in diaphragm than EDL muscle but demonstrated a greater age-related decline. The present study indicates that ability to sustain skeletal muscle power output through repetitive contraction is age- and muscle-dependent, which may help rationalize previously reported equivocal results from examination of the effect of age on muscular endurance. The age-related decline in EDL muscle performance is prevalent without a significant reduction in muscle mass, and biochemical analysis of key marker enzymes suggests that although there is some evidence of a more oxidative fiber type, this is not the primary contributor to the early age-related reduction in muscle contractility.

scholarly journals The influence of temperature on muscle function in the fast swimming scup. II. The mechanics of red muscle

1992 ◽  
Vol 163 (1) ◽  
pp. 281-295 ◽  
Author(s):  
L. C. Rome ◽  
A. Sosnicki ◽  
I. H. Choi
Keyword(s):  
Isometric Force ◽  
Maximum Velocity ◽  
Design Constraint ◽  
Velocity Of Shortening ◽  
Red Muscle ◽  
Different Temperatures ◽  
Influence Of Temperature On ◽  
The Mean ◽  
Important Design

To understand better how scup can swim twice as fast as carp with its red muscle, we measured the mechanical properties of red muscle bundles in scup. The values of the mean maximum velocity of shortening (Vmax) at 10 degrees C (3.32 muscle lengths s-1) and at 20 degrees C (5.55 muscle lengths s-1; Q10 = 1.69) were nearly the same as those in carp. Isometric force, however, was approximately 50% greater (183 kN m-2; Q10 = 1.08). The maximal power generation was correspondingly about 50% greater in scup than in carp (71 W kg-1 at 10 degrees C and 134 W kg-1 at 20 degrees C; Q10 = 1.88). The larger power output of its muscle may be important in the faster swimming of the scup. In addition, the fact that scup use a less undulatory style of swimming means that, when they are swimming twice as fast, their red muscle shortens at the same velocity (V) and with the same V/Vmax (0.37, i.e. where maximum power is generated) as that of carp. The importance of V/Vmax is further shown by the comparison of scup swimming at different temperatures. The 1.69-fold higher Vmax at 20 degrees C than at 10 degrees C enables scup to swim with a 1.67-fold faster V at 20 degrees C. Thus, at both 10 degrees C and 20 degrees C, red muscle is used only over the same narrow range of V/Vmax (0.17-0.37), where experiments on isolated muscle suggest that power and efficiency are maximal. Therefore, V/Vmax appears to be an important design constraint that limits the range of velocities over which muscle is used in vivo, both at different temperatures and in fast- and slow-locomoting species.

Influence of temperature on muscle recruitment and muscle function in vivo

1990 ◽  
Vol 259 (2) ◽  
pp. R210-R222 ◽  
Author(s):  
L. C. Rome
Keyword(s):  
Power Output ◽  
Maximum Velocity ◽  
Large Temperature ◽  
Fiber Types ◽  
Design Constraint ◽  
Sustainable Performance ◽  
Mechanical Power Output ◽  
Velocity Of Shortening ◽  
Influence Of Temperature On

Temperature has a large influence on the maximum velocity of shortening (Vmax) and maximum power output of muscle (Q10 = 1.5-3). In some animals, maximum performance and maximum sustainable performance show large temperature sensitivities, because these parameters are dependent solely on mechanical power output of the muscles. The mechanics of locomotion (sarcomere length excursions and muscle-shortening velocities, V) at a given speed, however, are precisely the same at all temperatures. Animals compensate for the diminished power output of their muscles at low temperatures by compressing their recruitment order into a narrower range of locomotor speeds, that is, recruiting more muscle fibers and faster fiber types at a given speed. By examining V/Vmax, I calculate that fish at 10 degrees C must recruit 1.53-fold greater fiber cross section than at 20 degrees C. V/Vmax also appears to be an important design constraint in muscle. It sets the lowest V and the highest V over which a muscle can be used effectively. Because the Vmax of carp slow red muscle has a Q10 of 1.6 between 10 and 20 degrees C, the slow aerobic fibers can be used over a 1.6-fold greater range of swim speeds at the warmer temperature. In some species of fish, Vmax can be increased during thermal acclimation, enabling animals to swim at higher speeds.

scholarly journals Scaling Effects on Muscle Function: Power Output of Isolated Fish Muscle Fibres Performing Oscillatory Work

1990 ◽  
Vol 151 (1) ◽  
pp. 453-467 ◽  
Author(s):  
JOHN D. ALTRINGHAM ◽  
IAN A. JOHNSTON
Keyword(s):  
Power Output ◽  
Fibre Length ◽  
Fish Muscle ◽  
Maximum Power ◽  
Muscle Fibres ◽  
Scaling Effects ◽  
Cycle Frequency ◽  
Maximum Power Output ◽  
Wide Range ◽  
Length Changes

Bundles of 3–10 live fast fibres were isolated from the abdominal myotomes of cod (Gadus morhua L.) 13–67 cm in length. The preparations performed work under conditions simulating their activity during swimming: sinusoidal length changes were imposed about in situ fibre length, and the fibres were stimulated at a selected phase in each cycle. Strain amplitude, and the number and timing of stimuli were chosen to give maximum power output over a wide range of cycle/tailbeat frequencies. For each preparation power output was maximal at a particular frequency, although the peaks were rather broad. As the size of the fish increased the cycle frequency for maximum power output (fopt) decreased, from 12.5 Hz (13 cm fish) to 5 Hz (67 cm fish) (fopt= 1.67 L−0.52, where L is body length).

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.

scholarly journals Power output and the frequency of oscillatory work in mammalian diaphragm muscle: the effects of animal size

1991 ◽  
Vol 157 (1) ◽  
pp. 381-389 ◽  
Author(s):  
J. D. Altringham ◽  
I. S. Young
Keyword(s):  
Body Mass ◽  
Power Output ◽  
Maximum Power ◽  
Diaphragm Muscle ◽  
Muscle Fibres ◽  
Cycle Frequency ◽  
Maximum Power Output ◽  
Oscillatory Power ◽  
Length Changes ◽  
Animal Size

Bundles of muscle fibres were isolated from the diaphragm of mouse, rat and rabbit. Mean oscillatory power output was determined during phasic stimulation and imposed sinusoidal length changes. Maximum power output was measured over a range of cycle frequencies. The cycle frequency for maximum power output (fopt) decreased with increasing body mass and was described by the equation, fopt = 4.42M-0.16, where M is body mass. A very similar relationship has been reported between body mass and the frequency of the trot-gallop transition in terrestrial, quadrupedal mammals [Heglund et al. (1974), Science 186, 1112–1113), and the significance of this similarity is discussed.

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