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At least 19 recordsLinked to original sources
PubMed1990

Costs of swimming measured at optimum speed: scale effects, differences between swimming styles, taxonomic groups and submerged and surface swimming.

1. Data on swimming energy expenditure of 30 submerged and nine surface swimmers, covering different swimming styles and taxonomic groups, are selected from the literature. 2. The costs of transport at the optimum speed are compared and related to body mass and Re numbers. 3. Fish and turtles use relatively less and most surface swimmers slightly more energy than the other submerged swimmers; man and mink are poorly adapted to swimming. 4. The metabolic rate in W at optimum speed is approximately equal to the body mass in kg for fish and turtles and three times the mass figure for the other submerged swimmers.

Animals↗
PubMed1992

A simple method for determining critical speed as swimming fatigue threshold in competitive swimming.

The purpose of this investigation was to determine whether the concept of the critical power could be applied to competitive swimming by using critical swimming speed (CS) as determined both in the swimming flume (CS-flume) and in the normal swimming pool (CS-pool) and whether CS could be utilized as a practical index for assessing a swimmer's endurance performance. CS defined as the swimming speed which could be theoretically maintained continuously without exhaustion was expressed as the slope of a regression line between swimming distance (D) and its duration (T) obtained at various swimming speeds. Eight highly trained swimmers were instructed to swim until onset of fatigue at four predetermined swimming speed levels in the swimming flume and at maximal effort over four different swimming distances in the swimming pool. In the results of CS-flume and CS-pool, the regression relations between D and T were expressed in the general form, D = a+b x T, with r2 being higher than 0.998 (p less than 0.01), respectively. These results both from the flume and the pool indicated extremely good linearity. Furthermore, maximal oxygen uptake (VO2max) during the incremental exercise test, swimming speed corresponding 4 mM of blood lactate concentration (V-OBLA) and mean velocity in the 400 m freestyle (V-400) were measured on each subject.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1986

Initiation of swimming activity by trigger neurons in the leech subesophageal ganglion. II. Role of segmental swim-initiating interneurons.

Cell Tr1, a trigger neuron found in the subesophageal ganglion of the leech, Hirudo medicinalis, is part of a network of subesophageal ganglion neurons which control swimming activity, and makes apparently direct connections to swim-initiating interneurons (SIIs; cells 204 and 205). In this study, we investigated the role of SIIs in swim initiation by cell Tr1. We also examined how brief Tr1 activity controls swim initiation at the levels of the SIIs and of the oscillator neurons. We found: In shortened nerve cord preparations consisting of the head ganglion (supra- and subesophageal ganglia) through segmental ganglia 11 or 12, the effectiveness of swim initiation by Tr1 stimulation was highly correlated with the concurrent injection of depolarizing or hyperpolarizing current into a single cell 204. Tr1 stimulation causes sustained excitation in SIIs, serotonin-containing interneurons and Retzius cells, independent of whether or not swimming is initiated. A short, depolarizing current pulse injected simultaneously into as many as three 204 cells does not replicate the sustained excitation evoked in these cells by Tr1 stimulation. An oscillator neuron, cell 208, is inhibited when Tr1 stimulation fails to elicit swimming, but receives excitatory input from Tr1 otherwise. In another oscillator neuron, cell 115, stimulation of Tr1 suppressed an unidentified source of inhibitory synaptic potentials only on trials which resulted in swim initiation. We conclude that Tr1 stimulation triggers swimming by activating a long-lasting ramp depolarization in the SIIs which, in turn, provide excitatory drive to the swim oscillator. Moreover, Tr1 initiates swimming only when inhibitory inputs to the swim oscillator are suppressed.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1992

The influence of temperature on muscle function in the fast swimming scup. I. Shortening velocity and muscle recruitment during swimming.

In this study, electromyography showed that scup can swim to a maximum speed of 80 cm s-1 with their red muscle whereas previous results showed that carp can swim to only 45 cm s-1. Our aim was to evaluate the adaptations that enable scup to swim nearly twice as fast as carp. Although we anticipated that, at their respective maximum speeds, the red muscle of scup would be shortening at twice the velocity (V) of carp muscle, we found that the values of V were the same (2.04 muscle lengths s-1). At any given swimming speed, V was higher in carp than in scup because carp had a larger sarcomere length excursion and higher tail-beat frequency. The smaller sarcomere excursion in scup is primarily associated with using a less undulatory style of swimming (i.e. with a smaller backbone curvature). This less undulatory style of swimming may be an important adaptation that not only reduces V but may also reduce drag. At their respective maximum speeds, however, the 28% lower sarcomere length excursion in scup is balanced by a 26% higher tail-beat frequency, giving an equal V to that of carp. Although the scup in this study were somewhat longer than the carp in the previous one (19.7 vs 13.4 cm), we believe that many of the observed differences are species-related rather than size-related. We also found that scup swam in a kinematically similar fashion at 10 degrees C and 20 degrees C. However, at 10 degrees C, the scup could swim to only 54 cm s-1 before recruiting their white muscle whereas, at 20 degrees C, they could swim to 80 cm s-1. The difference in speed of initial white muscle recruitment, as well as information on muscle mechanics, suggests that the scup compress their recruitment order into a narrow speed range at low temperatures, thereby recruiting more muscle fibres. Quantitative analysis of red muscle electromyograms in this paper supports this hypothesis.

Animals↗
PubMed1990

Neurobehavioral studies of forced swimming: the role of learning and memory in the forced swim test.

1. Immobility in the forced swim test ("behavioral despair test") has often been regarded as an animal model of despair or depression. 2. Behavioral studies of forced swimming ("behavioral despair") are reviewed and compared with certain behavioral effects of exposure to inescapable shock (i.e., "learned helplessness"). 3. Exposure to inescapable shock clearly impairs subsequent coping responses. However, detailed behavioral studies of forced swimming indicate that immobility during forced swimming is not a failure of coping but instead reflects a relatively successful coping strategy that employs energy conserving behaviors. 4. Certain neurobiological studies of forced swimming are reinterpreted in light of the behavioral evidence that immobility during forced swimming reflects effects of learning and memory rather than effects of despair or depression. 5. Some implications for future neurobehavioral studies of forced swimming and uncontrollable shock are discussed.

Animals↗
PubMed1989

Effects of ethanol on fight- or swim-stressed mice in Porsolt's swim test.

The effects of ethanol in Porsolt's swim test on mice preexposed to fight- or swim-stressors were investigated. The control mice did not change their behavior in the swim test after an acute injection of 0.4 or 0.8 g/kg ethanol; 1.2 g/kg ethanol increased their immobility in one but not in another experiment. The mice exposed to continuous fight-attacks in their home cage by one dominant mouse shortened immobility after 0.8 g/kg ethanol as well as tended to shorten it after 0.4 g/kg ethanol. The mice that were forced to swim in the water twice before the actual swim test responded to 0.4 g/kg ethanol by shortening immobility; 0.8 g/kg tended to have the same effect; 1.2 g/kg ethanol just failed to lengthen immobility of the fight-stressed mice and had no effect on the swim-stressed mice. Because antidepressant drugs decrease and stressors increase immobility in the swim test, the test may serve as a putative animal model of depression. The present findings showed that low doses of ethanol reverse lengthened immobility of mice preexposed to a stressor. This suggests that ethanol either has antidepressant-like properties, or it improves animal's ability to cope with a stressful situation, or both.

Aggression↗
PubMedDate not supplied

Enhancement of blood lactate clearance following maximal swimming. Effect of velocity of recovery swimming.

Swimming is an endurance-intensive sport resulting in accumulation of lactate. Repeat performances are often necessary in championship events. Lactate produced during a maximal effort requires time to metabolize to a base level. If this does not occur, performance in a repeat effort may be impaired. Thus, techniques to enhance lactate clearance are of potential benefit to the athlete. We have demonstrated previously that swimming at 65% of maximum velocity significantly improved lactate clearance over passive resting. This study tested the effect of various swimming velocities on lactate clearance. Following a maximal swim, blood lactate clearance was tracked during a 15 minute cool down swim. Velocities of 55%, 65%, and 75% of maximum were tested. The results confirmed that cool down swimming will return lactate values to near resting levels in the test interval. However, statistical superiority of any of the test velocities was not demonstrated. The intensity of the swim should be below the lactate accumulation level. The 65% of maximum velocity was felt by all swimmers to be most comfortable and is a good target velocity for the athlete to reference.

Anaerobic Threshold↗
PubMed1991

Effects of swimming and land exercises versus swimming and water exercises on body composition of college students.

The purpose of this study was to examine the effects of 2 different swimming and calisthenic exercise programs on body composition and swim performance. Subjects were forty-two students (M = 19; F = 23; mean age = 20.8 yr). The experimental groups (Swim-Land [SL], n = 14; Swim-Water, [SW], n = 16) participated in 35-40 min exercise sessions which consisted of a 5-10 min warm-up, 15-20 min of swimming, and 10-15 min of calisthenics three times per week for 8 weeks. The SL experimental group performed calisthenics on land with surgical tubing while the SW experimental group performed comparable calisthenics in the water. Subjects were pretested and posttested utilizing hydrostatic weighing to determine body density and calculate percent fat. Skinfold measures and the 12-min swim for distance were also measured. Results indicated a significant 20% increase in swim performance in both experimental groups (SL = 455 +/- 144 m to 553 +/- 114 m; SW = 465 +/- 122 m to 556 +/- 123 m; p less than 0.05) but no difference between groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Body Composition↗
PubMed1979

Swimming capacity of mice after prolonged treatment with psychostimulants. III. Effect of fencamfamine on swimming endurance and availability of metabolic substrates.

The effect of long-term treatment with fencamfamine on swimming endurance and availability of metabolic substrates was investigated in mice. Fencamfamine (14 micrograms/g per day orally for 6 weeks) reduced maximum swimming capacity by more than 40%. This effect could not be attributed to motor incoordination or a diminution of pre-swimming levels of metabolic substrates such as liver and muscle glycogen or blood glucose and non-esterfied fatty acids. However, during swimming the hepatic and muscular glycogen stores were depleted more rapidly in the fencamfamine-treated animals. Thus it appears that fencamfamine leads more rapidly to a shortage of combustible substrates in the swimming animals.

Adipose Tissue↗
PubMed1992

Screening of children with arrhythmias for arrhythmia development during diving and swimming--face immersion as a substitute for diving and exercise stress testing as a substitute for swimming.

We compared face immersion and exercise stress testing by diving and swimming as screening methods for arrhythmias induced by immersion in water. The subjects were 64 children with various arrhythmias who were tested using 5 methods: diving, swimming, face immersion in 25 degrees C water, face immersion in 6 degrees C water, and a treadmill exercise test. Significant arrhythmias occurred during diving or swimming in 51 children, with 44 developing arrhythmias while diving. Both tachyarrhythmias and bradyarrhythmias were seen during diving, but 17 children who also showed significant arrhythmias while swimming mostly had tachyarrhythmias. A comparison with the incidence of arrhythmias produced by diving showed that face immersion in cold water had a sensitivity of 88.6%, a specificity of 85.0%, a predictive value of 92.9%, and an accuracy of 87.5%. Arrhythmias were alleviated in 12.5%, unchanged in 79.7%, and aggravated in 7.8% of the subjects. Face immersion thus appeared to be a useful and adequate screening substitute for diving. Exercise testing was also compared with swimming (sensitivity, 52.9%; specificity, 100%; predictive value, 100%; and accuracy, 87.5%). Arrhythmias were alleviated in 12.5% and unchanged in 87.5% of patients. Although exercise testing produced many false-negatives, all of the severe arrhythmias were reproduced.

Adolescent↗
PubMed1991

A comparison of swim-down and swim-up methods for the extraction of high motility sperm.

High quality motile sperm are essential for the success of the in vitro fertilization-embryo transfer program and related procedures, for the performance of sperm antibody assays, and other in vitro tests of sperm function. Two methods for the extraction of high motility sperm, swim-down and swim-up, were compared on 30 ejaculates, and sperm motility was assessed at intervals up to 18 hours. The swim-down method was simpler, shorter, and provided a significantly better recovery of sperm with sustained high motility than did the swim-up method.

Analysis of Variance↗
PubMed1979

Swimming capacity of mice after prolonged treatment with psychostimulants. II. Effect of methamphetamine on swimming performance and availability of metabolic substrates.

Swimming endurance and availability of metabolic substrates (blood glucose and nonesterified fatty acids [NEFA], liver and muscle glycogen, body fat) were studied in mice treated with 10 microgram/g methamphetamine/day for 6 weeks. At the end of the 6-week treatment, motor coordination of the methamphetamine-treated animals was much better than that of controls, and swimming capacity tended to increase. While swimming, mice treated with methamphetamine mobilized more glycogen from the hepatic stores and utilized glucose more effectively. Their NEFA levels in blood were higher than those of controls. There was no difference in the muscular glycogen content.

Animals↗
PubMed1991

Stress analgesia: the opioid analgesia of long swims suppresses the non-opioid analgesia induced by short swims in mice.

In mice, room temperature swimming for as short a period as 15 sec has been found to induce a non-opioid analgesia with a time course of 10-12 min. As the duration of the swim is increased, an opioid analgesia develops with a longer persistence (25-30 min); the development of the opioid analgesia appears to suppress the expression of the non-opioid analgesia so that none of the latter is evident after 3 min swims. The characteristics of the tail-flick nociceptive test are also described.

Analgesia↗
PubMed1991

Myofilament overlap in swimming carp. II. Sarcomere length changes during swimming.

This study was performed to determine myofilament overlap during swimming in carp. By using frozen sections, we found that sarcomere lengths of the red and white muscle could be related to the curvature of the backbone. Sarcomere length (SL) during swimming was calculated from an analysis of backbone curvature in high-speed motion pictures. Because carp have the same myofilament lengths as frogs, we related force generation to SL using the frog SL-tension curve. At slow swimming speeds, the red fibers are used at a SL of 1.91-2.22 microns, where force generation is calculated to be no less than 96% maximal. If the red fibers powered the escape response they would have to shorten to 1.45-1.55 microns, where force generation would be reduced to approximately 50% maximal and the fibers damaged. Instead, the white muscle fibers are recruited and because of their helical orientation (resulting in a higher gear ratio), they shorten to only 1.75 microns, where they generate no less than 85% maximal tension. Thus, by recruitment of fiber types with different orientations, the full range of movements is powered by fibers operating at nearly maximal overlap. This suggests that myofilament overlap is an important design constraint of muscular systems.

Actin Cytoskeleton↗
PubMed1992

"Swimming-induced head twitching" in rats in the forced swimming test induced by overcrowding stress: a new marker in the animal model of depression?

We have used overcrowding stress to study the pathogenesis of depression and the action of antidepressant drugs. In the present study, the influence of overcrowding on behavior was assessed by the forced swimming test. All the stressed rats revealed highly characteristic head twitching movement, which was not inhibited by repeated administration of diazepam and haloperidol, but was markedly suppressed by repeated administration of desipramine and mianserine. A significant positive correlation in the number of twitching episodes in each stressed rat between the first and second forced swimming test was seen. These findings support the use of overcrowding of rats as a stressor in the animal depression model because it fulfills the criteria of the model; face validity, construct validity and predictive validity. We propose the adoption of "swimming head twitching" as a new marker in the animal model of depression.

Animals↗
PubMed1978

Swimming capacity of mice after prolonged treatment with psychostimulants. I. Effects of caffeine on swimming performance and cold stress.

A comparative study of the effects of a single dose of caffeine (50 microgram/g s.c.) and of 6-weeks treatment with 150 microgram/g p.o. caffeine/day on swimming capacity and resistance to cold exposure was performed in mice. In contrast to acute treatment, chronic treatment with caffeine greatly reduced the swimming capacity and diminished the ability of the animals to withstand cold stress. It could be shown by indirect means that the detrimental effect of the prolonged treatment with caffeine was not due to an accumulation of toxic levels of caffeine. Motor coordination was unaffected. There was no deficiency of metabolic substrates, since glycogen, and fat stores, and blood glucose, and fatty acid levels were not lower than in control animals. It is proposed that caffeine may interfere with the animals' ability to mobilize and spend metabolic substrates for energy requirements of skeletal muscle.

Animals↗
PubMed1989

The effect of swimming in asthmatic children--participants in a swimming program in the city of Baltimore.

Forty-five asthmatic children were enrolled in a swimming program in Baltimore. After participating in a 2-month swimming session, the children showed significant improvement in all clinical variables including symptoms, hospitalizations, emergency room visits, and school absenteeism compared with their previous medical history or to those of age-matched controls. These health benefits continued to be observed even 12 months after the session had been completed. The implications of these findings and the potential usefulness of adding sports programs as adjunct therapy in the comprehensive care of asthma in children are discussed.

Asthma↗