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

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.

1990 ◽  
Vol 154 (1) ◽  
pp. 163-178 ◽  
Author(s):  
LAWRENCE C. ROME ◽  
R. MCNEILL ALEXANDER

The aim of this study was to evaluate how fish locomote at different muscle temperatures. Sarcomere length excursion and muscle shortening velocity, V, were determined from high-speed motion pictures of carp, Cyprinus carpio (11–14 cm), swimming steadily at various sustained speeds at 10, 15 and 20°C. In the middle and posterior regions of the carp, sarcomeres of the lateral red muscle underwent cyclical excursions of 0.31 μm, centred around the resting length of 2.06 μm (i.e. from 1.91 to 2.22 μm). The amplitudes of the sarcomere length excursions were essentially independent of swimming speed and temperature. As tail-beat frequency increased linearly with swimming speed regardless of temperature, the sarcomeres underwent the same length changes in a shorter time. Thus, V increased in a linear and temperature-independent manner with swimming speed. Neither temperature nor swimming speed had an influence on tail-beat amplitude or tail height. Our findings indicate that muscle fibres are used only over a narrow, temperature-independent range of V/Vmax (0.17-0.36) where power and efficiency are maximal. Carp start to recruit their white muscles at swimming speeds where the red muscle V/Vmax becomes too high (and thus power output declines). When the V/Vmax of the active muscle falls too low during steady swimming, carp switch to ‘burst-and-coast’ swimming, apparently to keep V/Vmax high. Because Vmax (maximum velocity of shortening) of carp red muscle has a Q10 of 1.63, the transition speeds between swimming styles are lower at lower temperatures. Thus, carp recruit their white anaerobic muscle at a lower swimming speed at lower temperatures (verified by electromyography), resulting in a lower maximum sustainable swimming speed. The present findings also indicate that, to generate the same total force and power to swim at a given speed, carp at 10°C must recruit about 50% greater fibre cross-sectional area than they do at 20°C. Note: Present address: Department of Plant Molecular Biology, University of Tennessee, Knoxville, TN 37996, USA. Present address: Department of Pure and Applied Biology, University of Leeds, Leeds LS2 9JT, England.


1971 ◽  
Vol 55 (2) ◽  
pp. 489-520 ◽  
Author(s):  
P. W. WEBB

1. The wavelength, tail-beat frequency and trailing-edge amplitude have been measured for five groups of rainbow trout at various subfatigue cruising speeds. Four groups of fish were fitted with extra drag loads. The swimming mode was anguilliform by definition, but is probably best considered as intermediate between this and the carangiform mode. 2. The wavelength of the propulsive wave represented 0.76 of the body length. The specific amplitude (amplitude/length) tended to reach a maximum value of 0.175 at tail-beat frequencies approaching 5/sec. 3. The product of frequency and specific amplitude was found to be linearly related to swimming speed in all five groups of fish. 4. The critical swimming speed for the non-loaded control group was 1.73 body length/sec, and fell in groups 1-4 as the magnitude of the extra drag loads increased. The critical swimming speed for the control group is low for salmonids, probably as a result of the unfavourable history of the fish. 5. A method is described for calculating the drag of a swimming fish from the effects of the extra loads on the characteristics of the propulsive wave. It was found that thrust, T = 7.9 (swimming speed)1.79. The thrust was approximately 2.8 times greater than that required for an equivalent straight rigid vehicle. 6. It was calculated that the power output of the red muscle system would need to be about 0.48-0.77 ergs/sec/g muscle to overcome the drag of the fish at cruising speeds. 7. The power output of the fish was compared with values calculated by means of mathematical models proposed by Taylor and Lighthill. It was found that the fish did not fit the assumptions made in Taylor's model, and so power output calculations were not comparable with those calculated in the present paper. Lighthill's model was found to give values which were within 5 % of the values calculated here at higher swimming speeds. At lower swimming speeds the values were up to about 50 % lower than expected because again the fish did not fit the assumptions involved. 8. The relationship between thrust and swimming speed was extended into the sprint-speed range. It was calculated that fish could reach a maximum sprint speed maintained for 1 sec, provided that drag was reduced by about a half, or that the power required was that to accelerate the fish to that speed.


1988 ◽  
Vol 140 (1) ◽  
pp. 287-299 ◽  
Author(s):  
DARRELL R. STOKES ◽  
ROBERT K. JOSEPHSON

The mechanical power output was measured from scaphognathite (SG = gill bailer) muscle L2B of the crab Carcinus maenas (L.). The work was determined from the area of the loop formed by plotting muscle length against force when the muscle was subjected to sinusoidal length change (strain) and phasic stimulation in the length cycle. The stimulation pattern (10 stimuli per burst, burst length = 20% of cycle length) mimicked that which has been recorded from muscle L2B in intact animals. Work output was measured at cycle frequencies ranging from 0.5 to 5 Hz. The work output at optimum strain and stimulus phase increased with increasing cycle frequency to a maximum at 2–3 Hz and declined thereafter. The maximum work per cycle was 2.7 J kg−1 (15 °C). The power output reached a maximum (8.8 W kg−1) at 4 Hz. Both optimum strain and optimum stimulus phase were relatively constant over the range of burst frequencies examined. Based on the fraction of the total SG musculature represented by muscle L2B (18%) and literature values for the oxygen consumption associated with ventilation in C. maenas and for the hydraulic power output from an SG, we estimate that at a beat frequency of 2 Hz the SG muscle is about 10% efficient in converting metabolic energy to muscle power, and about 19% efficient in converting muscle power to hydraulic power.


1990 ◽  
Vol 149 (1) ◽  
pp. 61-78 ◽  
Author(s):  
R. D. STEVENSON ◽  
ROBERT K. JOSEPHSON

1. Mechanical work output was determined for an indirect flight muscle, the first dorsoventral, of the tobacco hawkmoth Manduca sexta. Work output per cycle was calculated from the area of force-position loops obtained during phasic electrical stimulation (1 stimulus cycle−1) and imposed sinusoidal length change. There was an optimal stimulus phase and an optimal length change (strain) that maximized work output (loop area) at constant cycle frequency and temperature. 2. When cycle frequency was increased at constant temperature, work output first increased and then decreased. It was always possible to find a frequency that maximized work output. There also always existed a higher frequency (termed the ‘optimal’ frequency in this paper) that maximized the mechanical power output, which is the product of the cycle frequency (s−1) and the work per cycle (J). 3. As temperature increased from 20 to 40°C, the mean maximum power output increased from about 20 to about 90 W kg−1 of muscle (Q10=2.09). There was a corresponding increase in optimal frequency from 12.7 to 28.3 Hz, in the work per cycle at optimal frequency from 1.6 to 3.2Jkg−1 muscle and in mean optimal strain from 5.9 to 7.9%. 4. Two electrical stimuli per cycle cannot increase power output at flight frequencies, but if frequency is reduced then power output can be increased with multiple stimulation. 5. Comparison of mechanical power output from muscle and published values of energy expenditure during free hovering flight of Manduca suggests that mechanical efficiency is about 10%. 6. In the tobacco hawkmoth there is a good correspondence between, on the one hand, the conditions of temperature (35–40°C) and cycle frequency (28–32 Hz) that produce maximal mechanical power output in the muscle preparation and, on the other hand, the thoracic temperature (35–42°C) and wing beat frequency (24–32 Hz) observed during hovering flight.


2001 ◽  
Vol 204 (3) ◽  
pp. 409-418 ◽  
Author(s):  
L.C. Rome ◽  
D.M. Swank

Ectothermal animals are able to locomote in a kinematically similar manner over a wide range of temperatures. It has long been recognized that there can be a significant reduction in the power output of muscle during swimming at low temperatures because of the reduced steady-state (i.e. constant activation and shortening velocity) power-generating capabilities of muscle. However, an additional reduction in power involves the interplay between the non-steady-state contractile properties of the muscles (i.e. the rates of activation and relaxation) and the in vivo stimulation and length change pattern the muscle undergoes during locomotion. In particular, it has been found that isolated scup (Stenotomus chrysops) red muscle working under in vivo stimulus and length change conditions (measured in warm-acclimated scup swimming at low temperatures) generates very little power for swimming. Even though the relaxation of the muscle has slowed greatly, warm-acclimated fish swim with the same tail-beat frequencies and the same stimulus duty cycles at cold temperatures, thereby not affording the slow-relaxing muscle any extra time to relax. We hypothesize that considerable improvement in the power output of the red muscle at low temperatures could be achieved if cold acclimation resulted in either a faster muscle relaxation rate or in the muscle being given more time to relax (e.g. by shortening the stimulus duration or reducing the tail-beat frequency). We test these hypotheses in this paper and the accompanying paper. Scup were acclimated to 10 degrees C (cold-acclimated) and 20 degrees C (warm-acclimated) for at least 6 weeks. Electromyograms (EMGs) and high-speed cine films were taken of fish swimming steadily at 10 degrees C and 20 degrees C. At 10 degrees C, we found that, although there were no differences in tail-beat frequency, muscle strain or stimulation phase between acclimation groups, cold-acclimated scup had EMG duty cycles approximately 20 % shorter than warm-acclimated scup. In contrast at 20 degrees C, there was no difference between acclimation groups in EMG duty cycle, nor in any other muscle length change or stimulation parameter. Thus, in response to cold acclimation, there appears to be a reduction in EMG duty cycle at low swimming temperatures that is probably due to an alteration in the operation of the pattern generator. This novel acclimation probably improves muscle power output at low temperatures compared with that of warm-acclimated fish, an expectation we test in the accompanying paper using the work-loop technique.


1997 ◽  
Vol 200 (22) ◽  
pp. 2907-2912 ◽  
Author(s):  
G N Askew ◽  
I S Young ◽  
J D Altringham

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.


1993 ◽  
Vol 178 (1) ◽  
pp. 97-108 ◽  
Author(s):  
P. W. Webb

Kinematics and steady swimming performance were recorded for steelhead trout (approximately 12.2 cm in total length) swimming in channels 4.5, 3 and 1.6 cm wide in the centre of a flume 15 cm wide. Channel walls were solid or porous. Tail-beat depth and the length of the propulsive wave were not affected by spacing of either solid or porous walls. The product of tail-beat frequency, F, and amplitude, H, was related to swimming speed, u, and to harmonic mean distance of the tail from the wall, z. For solid walls: FH = 1.01(+/−0.31)u0.67(+/−0.09)z(0.12+/−0.02) and for grid walls: FH = 0.873(+/−0.302)u0.74(+/−0.08)z0.064(+/−0.024), where +/−2 s.e. are shown for regression coefficients. Thus, rates of working were smaller for fish swimming between solid walls, but the reduction due to wall effects decreased with increasing swimming speed. Porous grid walls had less effect on kinematics, except at low swimming speeds. Spacing of solid walls did not affect maximum tail-beat frequency, but maximum tail-beat amplitude decreased with smaller wall widths. Maximum tail-beat amplitude similarly decreased with spacing between grid walls, but maximum tail-beat frequency increased. Walls also reduced maximum swimming speed. Wall effects have not been adequately taken into account in most studies of fish swimming in flumes and fish wheels.


1986 ◽  
Vol 122 (1) ◽  
pp. 1-12 ◽  
Author(s):  
KARIN VON SECKENDORFF HOFF ◽  
RICHARD JOEL WASSERSUG

The kinematics of swimming in larval Xenopus laevis has been studied using computer-assisted analysis of high-speed (200 frames s−1) ciné records. The major findings are as follows. 1. At speeds below 6 body lengths (L) per second, tail beat frequency is approximately 10 Hz and, unlike for most aquatic vertebrates, is not correlated with specific swimming speed. At higher speeds, tail beat frequency and speed are positively correlated. 2. Xenopus tadpoles show an increase in the maximum amplitude of the tail beat with increasing velocity up to approximately 6Ls−1. Above that speed amplitude approaches an asymptote at 20 % of body length. 3. Anterior yaw is absent at velocities below 6Ls−1, unlike for other anuran larvae, but is present at higher speeds. 4. At speeds below 6Ls−1 there is a positive linear relationship between length of the propulsive wave (λ) and specific swimming speed. At higher speeds wavelength is constant at approximately 0.8L. 5. There is a shift in the modulation of wavelength and tail beat frequency with swimming speed around 5.6Ls−1, suggesting two different swimming modes. The slower mode is used during open water cruising and suspension feeding. The faster, sprinting mode may be used to avoid predators. 6. Froude efficiencies are similar to those reported for fishes and other anuran larvae. 7. Unlike Rana and Bufo larvae, the axial muscle mass of Xenopus increases dramatically with size from less than 10% of total mass for the smallest animals to more than 45% of total mass for the largest animals. This increase is consistent with maintaining high locomotor performance throughout development.


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