scholarly journals Modeling red muscle power output during steady and unsteady swimming in largemouth bass

1994 ◽  
Vol 267 (2) ◽  
pp. R481-R488 ◽  
Author(s):  
T. P. Johnson ◽  
D. A. Syme ◽  
B. C. Jayne ◽  
G. V. Lauder ◽  
A. F. Bennett
Keyword(s):  
Power Output ◽  
Largemouth Bass ◽  
Muscle Power ◽  
Micropterus Salmoides ◽  
Cycle Frequency ◽  
Red Muscle ◽  
Slow Twitch ◽  
Work Done

We recorded electromyograms of slow-twitch (red) muscle fibers and videotaped swimming in the largemouth bass (Micropterus salmoides) during cruise, burst-and-glide, and C-start maneuvers. By use of in vivo patterns of stimulation and estimates of strain, in vitro power output was measured at 20 degrees C with the oscillatory work loop technique on slow-twitch fiber bundles from the midbody area near the soft dorsal fin. Power output increased slightly with cycle frequency to a plateau of approximately 10 W/kg at 3-5 Hz, encompassing the normal range of tail-beat frequencies for steady swimming (approximately 2-4 Hz). Power output declined at cycle frequencies simulating unsteady swimming (burst-and-glide, 10 Hz; C-start, 15 Hz). However, activating the muscle at 10 Hz did significantly increase the net work done compared with the work produced by the inactive muscle (work done by the viscous and elastic components). Thus this study provides further insight into the apparently paradoxical observation that red muscle can contribute little or no power and yet continues to show some recruitment during unsteady swimming. Comparison with published values of power requirements from oxygen consumption measurements indicates a limit to steady swimming speed imposed by the maximum power available from red muscle.

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.

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 The effect of cycle frequency on the power output of rat papillary muscles in vitro.

1995 ◽  
Vol 198 (4) ◽  
pp. 1035-1043 ◽  
Author(s):  
J Layland ◽  
I S Young ◽  
J D Altringham
Keyword(s):  
Phase Shift ◽  
Strain Amplitude ◽  
Power Output ◽  
Maximum Power ◽  
Papillary Muscles ◽  
Cycle Frequency ◽  
Maximum Power Output ◽  
Work Production

Papillary muscles were isolated from the right ventricles of rats and the length for maximum active force generation (Lmax) was determined isometrically. The work loop technique was used to derive the length for maximum work production (Lopt) at the cycle frequency, strain amplitude and stimulation phase shift found to be optimal for power output. Lopt was typically 7% shorter than Lmax and within the physiological length range (87.5% Lmax to Lmax). Net work and power output were measured during sinusoidal strain cycles around Lopt, over the cycle frequency range 1-9 Hz, strain amplitude and phase shift being optimised for work and power at each frequency. Experiments were performed at 37 degrees C. Distinct optima were found in both the work-frequency and the power-frequency relationships. The optimum cycle frequency for net work production was lower than the frequency for maximum power output. The mean maximum power output at 37 degrees C was 8.62 +/- 0.50 W kg-1 (mean +/- S.E.M., N = 9) and was achieved at a cycle frequency of approximately 6 Hz, close to the estimated resting heart rate of 5.8 Hz for the rats used (mean mass 223 +/- 25 g). The cycle frequency, strain amplitude and stimulation phase shift found to be optimal for power output produced an in vitro contraction closely simulating the basal in vivo contraction.

Power production during steady swimming in largemouth bass and rainbow trout

2000 ◽  
Vol 203 (3) ◽  
pp. 617-629 ◽  
Author(s):  
D.J. Coughlin
Keyword(s):  
Rainbow Trout ◽  
Largemouth Bass ◽  
Muscle Activity ◽  
Power Production ◽  
Emg Activity ◽  
Published Data ◽  
Red Muscle ◽  
Work Loop

Steady swimming in fishes is powered by the aerobic or red muscle, but there are conflicting theories on the relative roles of the anterior and posterior red muscle in powering steady swimming. To examine how red muscle is used to power steady swimming in rainbow trout (Oncorhynchus mykiss), electromyographic (EMG) and sonomicrometry recordings were made of muscle activity in vivo. These data were used in in vitro work-loop studies of muscle power production. Data on in vitro power production were also collected for largemouth bass (Micropterus salmoides) red muscle from previously published data on in vivo muscle activity. The in vivo data collected from swimming trout were similar to those for other species. The anterior red muscle of these fish has the longest duty cycle, the smallest phase shift between the onset of EMG activity and maximum muscle length during each tailbeat and undergoes the smallest strain or length change. For both trout and largemouth bass, work-loop experiments indicate that the majority of power for steady swimming is generated by the posterior muscle, as has been observed in other species.

scholarly journals Mechanical efficiency and efficiency of storage and release of series elastic energy in skeletal muscle during stretch-shorten cycles.

1996 ◽  
Vol 199 (9) ◽  
pp. 1983-1997
Author(s):  
G J Ettema
Keyword(s):  
Elastic Energy ◽  
Muscle Power ◽  
Mechanical Energy ◽  
Mechanical Efficiency ◽  
Contractile Element ◽  
Cycle Frequency ◽  
External Work ◽  
Work Done ◽  
Series Elastic

The mechanical energy exchanges between components of a muscle-tendon complex, i.e. the contractile element (CE) and the series elastic element (SEE), and the environment during stretch-shorten cycles were examined. The efficiency of the storage and release of series elastic energy (SEE efficiency) and the overall mechanical efficiency of the rat gastrocnemius muscle (N = 5) were determined for a range of stretch-shorten contractions. SEE efficiency was defined as elastic energy released to the environment divided by external work done upon the muscle-tendon complex plus internal work exchange from the CE to the SEE. Mechanical efficiency is external work done by the muscle-tendon complex divided by the external work done upon the muscle-tendon complex plus work done by the CE. All stretch-shorten cycles were performed with a movement amplitude of 3mm (6.7% strain). Cycle frequency, duty factor and the onset of stimulation were altered for the different cycles. SEE efficiency varied from 0.02 to 0.85, mechanical efficiency from 0.43 t 0.92. SEE efficiency depended on the timing of stimulation and net muscle power in different ways. Mechanical efficiency was much more closely correlated with net power. The timing of muscle relaxation was crucial for the effective release of elastic energy. Simulated in vivo contractions indicated that during rat locomotion the gastrocnemius may have a role other than that of effectively storing elastic energy and generating work. Computer simulations showed that the amount of series elastic compliance can affect the internal energetics of a muscle contraction strongly without changing the muscle force generation dramatically.

scholarly journals The mechanical properties of fast and slow skeletal muscles of the mouse in relation to their locomotory function.

1995 ◽  
Vol 198 (2) ◽  
pp. 491-502 ◽  
Author(s):  
R S James ◽  
J D Altringham ◽  
D F Goldspink
Keyword(s):  
Power Output ◽  
Sarcomere Length ◽  
Emg Activity ◽  
Force Curve ◽  
Maximal Power ◽  
Mean Power ◽  
Cycle Frequency ◽  
Mean Power Output

The mechanical properties of soleus and extensor digitorum longus (EDL) muscles from the mouse were studied using the work loop technique. Under optimum conditions, the EDL produced a maximum mean power output of 107 W kg-1 at a cycle frequency of 10 Hz. In comparison, the maximum mean power output of the soleus was 34 W kg-1 at 5 Hz cycle frequency. Video analysis of mice determined the stride frequency range to be from 2.87 Hz at a walk to 8.23 Hz at a flat-out gallop, with the trot-to-gallop transition occurring at 5.89 Hz. In vivo EDL electromyogram (EMG) activity is recorded primarily during shortening and the muscle operates in a power-generating mode. The soleus is close to isometric when EMG activity is recorded, but mechanical activity persists into the shortening phase. Both muscles are likely to operate over cycle frequency ranges just below, or at, those yielding maximal power. Soleus and EDL produced maximal power output in vitro when operating at mean sarcomere lengths of 2.58 microns and 2.71 microns respectively. These lengths are slightly above the plateau of the length-force curve predicted for rat leg muscle (2.3-2.5 microns). The sarcomere length ranges used in vivo by the soleus and EDL were determined, by fixing muscles in the extreme active positions predicted from video and cine analysis, to be 2.28-2.57 microns and 2.49-2.88 microns respectively. These ranges are both close to those shown to yield maximum power output in vitro and to the plateau of the sarcomere length-force curve.

Fatigue of mouse soleus muscle, using the work loop technique.

1997 ◽  
Vol 200 (22) ◽  
pp. 2907-2912 ◽  
Author(s):  
G N Askew ◽  
I S Young ◽  
J D Altringham
Keyword(s):  
Soleus Muscle ◽  
Power Output ◽  
Cycle Frequency ◽  
Reduction In Force ◽  
Negative Work ◽  
Loop Shape ◽  
Force Velocity ◽  
Positive Work ◽  
Work Loop

The function of many muscles requires that they perform work. Fatigue of mouse soleus muscle was studied in vitro by subjecting it to repeated work loop cycles. Fatigue resulted in a reduction in force, a slowing of relaxation and in changes in the force-velocity properties of the muscle (indicated by changes in work loop shape). These effects interacted to reduce the positive work and to increase the negative work performed by the muscle, producing a decline in net work. Power output was sustained for longer and more cumulative work was performed with decreasing cycle frequency. However, absolute power output was highest at 5 Hz (the cycle frequency for maximum power output) until power fell below 20% of peak power. As cycle frequency increased, slowing of relaxation had greater effects in reducing the positive work and increasing the negative work performed by the muscle, compared with lower cycle frequencies.

Slow muscle induction by Hedgehog signalling in vitro

2000 ◽  
Vol 113 (15) ◽  
pp. 2695-2703 ◽  
Author(s):  
W. Norris ◽  
C. Neyt ◽  
P.W. Ingham ◽  
P.D. Currie
Keyword(s):  
Cell Fate ◽  
Sonic Hedgehog ◽  
Culture System ◽  
Early Embryo ◽  
Extrinsic Factors ◽  
Fast Myosin ◽  
Neural Input ◽  
Slow Twitch

Muscles are composed of several fibre types, the precise combination of which determines muscle function. Whereas neonatal and adult fibre type is influenced by a number of extrinsic factors, such as neural input and muscle load, there is little knowledge of how muscle cells are initially determined in the early embryo. In the zebrafish, fibres of the slow twitch class arise from precociously specified myoblasts that lie close to the midline whereas the remainder of the myotome differentiates as fast myosin expressing muscle. In vivo evidence has suggested the Sonic Hedgehog glycoprotein, secreted from the notochord, controls the formation of slow twitch and fast twitch muscle fates. Here we describe an in vitro culture system that we have developed to test directly the ability of zebrafish myoblasts to respond to exogenous Sonic Hedgehog peptide. We find that Sonic Hedgehog peptide can control the binary cell fate choice of embryonic zebrafish myoblasts in vitro. We have also used this culture system to assay the relative activities of different Hedgehog-family proteins and to investigate the possible involvement of heterotrimeric G-proteins in Hedgehog signal transduction.

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.

Minimum intracellular PO2 for maximum cytochrome turnover in red muscle in situ

1987 ◽  
Vol 252 (5) ◽  
pp. H906-H915 ◽  
Author(s):  
T. E. Gayeski ◽  
R. J. Connett ◽  
C. R. Honig
Keyword(s):  
Energy Demand ◽  
Concentration Ratio ◽  
Probability Distributions ◽  
Michaelis Constant ◽  
Cytochrome Aa3 ◽  
Wide Range ◽  
Red Muscle

Probability distributions of myoglobin (Mb) saturation and intracellular PO2 were determined with subcellular spatial resolution in dog gracilis muscles during steady-state twitch contraction at 5-100% of maximal rate of O2 consumption (VO2). Calculations (Clark, A., and P. A.A. Clark. Biophys. J. 48: 931-938, 1985) and measurements (Gayeski, T. E. J., and C. R. Honig. Adv. Exp. Med. Biol. 200: 487-494, 1986) indicate that the PO2 in equilibrium with Mb is virtually identical to the PO2 at cytochrome aa3. Median intracellular PO2 and PO2 in the lower tails of probability distributions were poorly correlated with VO2. The variability of cell PO2 was greatly diminished when median PO2 was less than the PO2 for half saturation of MB, since Mb acts as a PO2 buffer. The lower tails of PO2 distributions contained almost no anoxic loci even when median PO2 was less than 1 Torr. VO2 was well correlated with the concentration ratio of phosphocreatine to free creatine (PCr/Crf) over a wide range of PO2. PO2 greater than or equal to 0.5 Torr supported maximal VO2 and energy demand. We conclude that 1) the mechanism of action of cytochrome aa3 is the same in red muscle in vivo as in mitochondria in vitro, and 2) an upper bound on the apparent Michaelis constant for maximal VO2 of red muscle is approximately 0.06 Torr.

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