PubMed Health⌕ Search

SEARCH · PubMed Health

Results for “SWIMMING”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 37 records · Page 2Linked to original sources

Forced swimming test in rats: effect of desipramine administration and the period of exposure to the test on struggling behavior, swimming, immobility and defecation rate.

The effect of desipramine administration and the duration of the daily exposure to forced swimming on some variables has been studied in adult male rats. Desipramine administration (15 mg/kg) significantly increased struggling behavior in the first and second 5-min periods of a single exposure to forced swimming. Swimming was reduced in the first 5 min and remained unchanged thereafter. Immobility was decreased in the second and the third 5-min periods. After a pre-exposure to forced swimming for 15 min the day before, the drug was effective in increasing struggling behavior and reducing immobility during a subsequent 5-min test. Swimming was not modified. Daily exposure to forced swimming for 3 days caused a decline in struggling behavior and swimming, while increasing immobility and the defecation rate. The duration of daily exposure to forced swimming did not alter the changes in the variables measured. The present results indicate that a one-day test can be used to discriminate between saline- and desipramine-treated rats, and that struggling behavior could be a reliable measure of the positive action of antidepressants. The finding that behavioral changes over the 3 days were independent of the duration of exposure to swimming argues against the interpretation of the results which suggest that the responses are caused by the appearance of a behavioral despair state, and suggests that these behaviors might be trait-markers in the rat. In addition, the changes in struggling behavior and immobility over the 3 days cannot be attributed to a behavioral adaptation to the test because the defecation rate increased rather than decreased during successive forced swimming tests.

Animals↗

The effect of a one-piece competition speedsuit on swimming performance and thermoregulation during a swim-cycle trial in triathletes.

This study investigated the thermoregulatory response to wearing a one-piece competition speedsuit during the swim-cycle aspect of a sprint-distance triathlon. Eight highly trained, male triathletes completed a graded-exercise test, and two swim-cycle trials including a 750 m swimming time trial followed by 30 min of cycling at 95% lactate threshold. Cycling was conducted inside a climate regulated chamber set to 30.0+/-0.3 degrees C and 60.3+/-0.3% humidity. Throughout each swim-cycle testing session, the athletes wore either standard swimming bathers only (BATHERS), or a competition speedsuit (SPEEDSUIT). During the swim-cycle trial, the athletes core temperature (T(c)) and skin temperature (T(sk)) were recorded via a telemetric temperature pill and a series of skin thermistors, respectively. Blood lactate concentration (BLa), heart rate (HR) and ratings of perceived thermal sensation (RPTS) were collected at the conclusion of the swim and during cycling. The SPEEDSUIT swim time (590+/-20s) was significantly faster (3.2%, p<0.01) than the BATHERS trial (609+/-24s). This time improvement incurred no between group differences in T(c), BLa or RPTS (SPEEDSUIT: 38.4+/-0.2 degrees C, 8.3+/-0.9 mmol L(-1), 15+/-1, BATHERS: 38.2+/-0.1 degrees C, 8.4+/-1.1 mmol(-1), 15+/-1, respectively) (p>0.05). During the 30 min cycle, there were not significant differences between the mean values for power output, T(c), T(sk), HR, BLa or RPTS (SPEEDSUIT: 289+/-13W, 38.65+/-0.27 degrees C, 34.30+/-0.71 degrees C, 7.8+/-1.1 mmol L(-1), 17+/-1, BATHERS: 288+/-14W, 38.35+/-0.10 degrees C, 33.50+/-0.57 degrees C, 7.1+/-0.9 mmol L(-1), 17+/-1, respectively) (p>0.05). The use of a competition speedsuit improved the triathletes' swim time without effecting temperature regulation during a laboratory-based swim-cycle trial.

Adult↗

Prolonged swimming, recovery and repeat swimming performance of mature sockeye salmon Oncorhynchus nerka exposed to moderate hypoxia and pentachlorophenol.

Mature, wild sockeye salmon (Oncorhynchus nerka) demonstrated their remarkable stamina and recovery abilities by performing three consecutive critical swimming speed tests with only a 45 min interval for recovery between subsequent tests. Although the repeated swimming challenges were performed without a full recovery, normoxic fish swam just as well on the second swim, and the majority of fish swam only marginally more poorly on the third swim. In addition, metabolic loading in these fish, as measured by the rate of oxygen consumption, ventilation rate and plasma lactate levels during recovery, did not appear to be cumulative with successive swims. Fish, however, did not recover as well after a similar level of initial swimming performance under moderately hypoxic conditions (water PO2>100 mmHg; 1 mmHg=0.1333 kPa). Four out of the five fish did not swim again and their high plasma lactate levels indicated a greater anaerobic effort. In another group of fish, metabolic loading (elevated control rates of oxygen consumption) was induced with an overnight sublethal exposure to pentachlorophenol, but these fish swam as well as normoxic fish on the first swim, and five of the six fish swam for a third time at a marginally lower critical swimming speed. In contrast to expectations, pentachlorophenol pretreatment and moderate hypoxia were not additive in their effects. Instead, the effects resembled those of pentachlorophenol pretreatment alone. The results are discussed in terms of what aspects of fatigue might impair the repeat swimming performance of sockeye salmon.

Animals↗

Effect of cold acclimation and repeated swimming on opioid and nonopioid swim stress-induced analgesia in selectively bred mice.

Swiss-Webster mice selectively bred for high swim stress-induced analgesia (SSIA) were exposed to continuous ambient cold (5 degrees C) for 6 weeks or to daily 3-min swims for 14 consecutive days either in 20 or 32 degrees C water. Thereafter, mice subjected to the particular procedure were injected intraperitoneally with 10 mg/kg of naltrexone HCl and were tested for modification of the opioid and nonopioid component of SSIA. SSIA was reduced following swims at either water temperature and was antagonized by naltrexone to greater extent than in nonswimming mice. Thus, the nonopioid (i.e. naltrexone-resistant) portion of the overall SSIA was significantly reduced, whereas the opioid (naltrexone-sensitive) portion became relatively augmented. In contrast, SSIA differed neither in magnitude nor in sensitivity to naltrexone between cold-acclimated and unacclimated mice. Swim hypothermia as well as the nonopioid component of SSIA were decreased after repeated swimming at 32 and 20 degrees C, but remained unchanged after cold acclimation. This argues for the essential role of an extrathermal, probably emotional in nature, factor not only in the elicitation of nonopioid SSIA, but also in the modulation of thermoregulatory processes during swimming. We suggest that the emergency component of swim stress, together with initial moderate hypothermic challenge, first produces the opioid form of SSIA, and subsequently, as the swim continues, also affects the thermoregulatory processes maintaining thermal homeostasis. This causes further increase in swim hypothermia and raises its stressing property to induce the nonopioid form of SSIA.

Acclimatization↗

Identification and characterization of cerebral ganglion neurons that induce swimming and modulate swim-related pedal ganglion neurons in Aplysia brasiliana.

1. We have identified and characterized a family of several pairs of neurons in the cerebral ganglion of Aplysia brasiliana that are capable of inducing, maintaining, or modulating a motor program that underlies swim locomotion in this marine mollusk. We have operationally defined these cells as command neurons (CNs) for swimming. 2. The command cells occur in bilateral pairs in the cerebral ganglion and make direct and indirect outputs to neurons in the pedal ganglia, including motor neurons, a central pattern generator circuit, and modulatory neurons that enhance muscle contractions during swimming. Several of the CNs are sufficient individually to induce the swim motor program (SMP), all receive sensory feedback from the periphery, and several interconnect with other swim-related CNs. 3. Tonic discharges of approximately 10 Hz in CN types 1-3 (CN1-CN3) are capable of eliciting the oscillatory, phasic SMP as recorded in peripheral nerves that innervate the swim appendages, the parapodia. CN1, CN2, and CN3 make monosynaptic excitatory connections onto ipsilateral, contralateral, and bilateral pedal swim-modulatory neurons [parapodial opener-phase (POP) cells], respectively; and each command cell type activates the pedal central pattern generator (CPG), leading to sustained phasic output of motor neurons and POP cells. 4. Tonic firing of CN4 causes weak activation of the SMP contralaterally. These neurons occur as two pairs of neurons in each cerebral hemiganglion, with mutual electrical and chemical synaptic interconnections. CN4 cells also excite CN1 and CN2 cells. Thus CN4 is classified as a higher-order swim command cell type. 5. Command cells classified as types 5-8 (CN5-CN8), although not capable of inducing the SMP individually, nonetheless have strong synaptic connections with pedal POP cells and/or with other command neurons. These command cells may excite or inhibit follower cells on the same or opposite sides of the preparation and modulate the swim output. 6. All the command cells tested received strong input from mechanical stimulation, either stretch or pinching, of either parapodium. Mechanosensory input from the parapodia was shown to depend on the presence of the pedal ganglion, but not the pleural. Sensory stimulation activated command cells and motor neurons, but POP cells received input from sensory stimuli only through the cerebral ganglion, probably via command cells. The effects of applied mechanosensory stimuli could be entirely mimicked by motor neuron-induced contractions of the parapodia.

Animals↗

Swimming and cleaning in the free-swimming phase of Argulus larvae (crustacea, branchiura)--appendage adaptation and functional morphology.

The free-swimming early larval stages of Argulus foliaceus (Linneaus) (Branchiura) are studied using digital video, light microscopy, and SEM. We analyze and document the mode of swimming in the hatching stage of A. foliaceus and the subsequent juvenile stages with fully developed thoracopods. We present new observations and an analysis of the functional morphology of a cleaning behavior in the first stage. This stage swims very efficiently using the large exopods of the second antennae in concert with the mandibular palp (naupliar limbs), while the subsequent stages use the now developed thoracopods for propulsion. This posterior shift in propulsion is similar to--but independent from--what is seen in other crustaceans. The hatching stage has previously been referred as a "metanauplius" but as the first and second maxillae are developed and active, and buds of all four thoracopods are present, it is too advanced to be included in the naupliar phase. The hooks of the first antennae and the distal hooks of the maxillae are demonstrated to function not only as attachment organs (to the host), but also to play a significant role in the cleaning of the naupliar swimming appendages. A digital video-based analysis of the swimming mode is provided. The larval swimming pattern is generally similar to that of other crustaceans such as Branchiopoda and Cirripedia, but autapomorphies of the Branchiura include the following: 1) While actively swimming, the naupliar appendages are almost straight during the recovery stroke and 2) they have a relatively small deflection during movement ( approximately 25 degrees or approximately 35 degrees for mandible and second antenna respectively), 3) the larval mandible has a uniramous palp which is the retained exopod. The morphological implications of the transition from the possibly nonfeeding pelagic, or free-swimming, first larval stage to the feeding, parasitic second stage are discussed and compared with other crustaceans.

Adaptation, Physiological↗

The effects of CRF antagonists, antalarmin, CP154,526, LWH234, and R121919, in the forced swim test and on swim-induced increases in adrenocorticotropin in rats.

RATIONALE: Exposure to extreme stress has been suggested to produce long-term, detrimental alterations in the hypothalamic-pituitary-adrenal (HPA) axis leading to the development of mental disorders such as depression. Therefore, compounds that block the effects of stress hormones were investigated as potential therapeutics for depression. OBJECTIVES: In the present study, we compared the potential antidepressant-like effects of four CRF antagonists, antalarmin, CP154,526, R121919, and LWH234 (at 3, 10, and 30 mg/kg i.p., 60 min prior to the forced swim test) and the corresponding effect on swim-induced HPA activation to better elucidate the relation between HPA activity and antidepressant activity. METHODS: The antidepressant-like effects of the CRF antagonists and known antidepressants were determined in the rat forced swim test, and blood samples were obtained before and after swimming for the evaluation of adrenocorticotropin-releasing hormone (ACTH) levels. RESULTS: Antalarmin, CP154,526, and R121919 did not produce antidepressant-like effects in the forced swim test although these compounds decreased swim-induced increases in ACTH to various extents. In contrast, LWH234 reduced immobility in the forced swim test, without altering the swim-stress-induced ACTH response. However, this compound antagonized restraint-induced ACTH release. CONCLUSIONS: These data suggest that reducing stress-induced increases in HPA activity alone may not be sufficient to produce antidepressant-like activity; however, reductions in HPA activity may contribute to antidepressant actions of some treatments. In addition, it is proposed that CRF antagonists may alter differentially the HPA axis depending on the type of stressor used or behavioral measure evaluated.

Adrenocorticotropic Hormone↗

Swimming efficiency and the influence of morphology on swimming costs in fishes.

Swimming performance is considered a main character determining survival in many aquatic animals. Body morphology highly influences the energetic costs and efficiency of swimming and sets general limits on a species capacity to use habitats and foods. For two cyprinid fishes with different morphological characteristics, carp (Cyprinus carpio L.) and roach (Rutilus rutilus (L.)), optimum swimming speeds (U(mc)) as well as total and net costs of transport (COT, NCOT) were determined to evaluate differences in their swimming efficiency. Costs of transport and optimum speeds proved to be allometric functions of fish mass. NCOT was higher but U(mc) was lower in carp, indicating a lower swimming efficiency compared to roach. The differences in swimming costs are attributed to the different ecological demands of the species and could partly be explained by their morphological characteristics. Body fineness ratios were used to quantify the influence of body shape on activity costs. This factor proved to be significantly different between the species, indicating a better streamlining in roach with values closer to the optimum body form for efficient swimming. Net swimming costs were directly related to fish morphology.

Animals↗

The effect of high- and low-intensity warm-up on the physiological responses to a standardized swim and tethered swimming performance.

This investigation was conducted to determine the effect of high- and low-intensity warm-ups on physiological responses, lactate accumulation, and high-intensity freestyle and tethered swimming performance. Ten male collegiate swimmers were tested for maximal oxygen uptake (VO2 max) followed by two series of three warm-up protocols performed in a randomized order at least 2 days apart. The warm-up protocols were: (1) no warm-up (NWU), (2) a 366-m swim at 70% VO2 max (LWU) and (3) four 46-m swims at 1-min intervals at a speed corresponding to 110% VO2 max (HWU). Five minutes after each warm-up in the first series, the swimmers swam a 183-m standardized freestyle swim at a velocity corresponding to 110% VO2 max, and 5 min after each warm-up in the second series the swimmers completed a tethered swim to exhaustion with a weight attached to the tether to elicit fatigue at about 2 min. Three minutes after each warm-up and 3 min after each standardized and tethered swim, a finger-prick blood sample for lactate measurement was obtained. Heart rate and VO2 were also measured during the warm-up and the standardized and tethered swims. The performance times in the tethered swim were not significantly different between the three conditions (116.8 +/- 46.8, 137 +/- 53.3 and 122.94 +/- 37.2 s for the NWU, LWU and HWU, respectively).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

Synaptic basis of swim initiation in the leech. III. Synaptic effects of serotonin-containing interneurones (cells 21 and 61) on swim CPG neurones (cells 18 and 208).

Serotonin-containing cells 21 and 61 strongly excite a swim central pattern generator (CPG) neurone, cell 208, in nearby segmental ganglia in the leech Macrobdella decora. This excitatory effect is apparently independent of activity in the swim-initiating neurone cell 204, which monosynaptically excites cell 208 (Weeks, 1982b). Cell 208 excites cell 21, apparently directly. This is the first identified direct pathway for feedback from the swim central pattern generator to a swim initiator neurone. Focally applied serotonin has no effect on the soma of cell 208, but causes both excitatory and inhibitory responses in cell 208 when applied to different places within the neuropile. Cell 61 polysynaptically excites distant, posterior cells 208. This excitation is mediated at least in part by the activation of nearby cells 208, which polysynaptically excite posterior cells 208. Cell 208 is dye-coupled intraganglionically to a newly identified pair of neurones, designated cells 18. Cell 208 also excites posterior cells 18, apparently directly. This interaction may be the pathway whereby cell 61 polysynaptically excites posterior cells 208. During swimming, cell 18's membrane potential oscillates in phase with cell 208. Intracellular current injection into cell 18 during swimming perturbs the swim motor pattern. Therefore, cell 18 qualifies as a candidate swim CPG neurone.

Animals↗

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↗

Semen preparation by standard swim-up versus swim-up with test yolk buffer incubation in intrauterine insemination: a randomized study.

In order to compare the standard swim-up semen preparation with and without test yolk buffer (TYB) incubation in intrauterine insemination (IUI), we conducted a prospective multicentre randomized trial. A total of 121 infertile couples with male factor (n = 52) or unexplained infertility (n = 69) was randomly assigned to two groups following ovulation induction. Semen was prepared by standard swim-up in group A (n = 64) and by swim-up followed by TYB incubation in group B (n = 57). A maximum of two IUI cycles was performed. A total of 104 cycles was performed in the swim-up group and 90 in the TYB group. Overall, 15 pregnancies were achieved in group A and 23 in group B, with an overall pregnancy rate of 24.8 and 50.0% per patient respectively (chi2(1), P < 0.05). In the male factor group, pregnancy was achieved in six out of 24 couples (25%) following standard swim-up and in six out of 28 (21.4%) following swim-up and TYB incubation (chi2(1), not significant). In the unexplained infertility group, pregnancy was recorded in nine out of 40 couples (22.5%) following standard swim-up and in 17 out of 29 couples (58.6%) following swim-up and TYB incubation (chi2(1), P < 0.05).

Female↗

Involvement of dopamine D2 receptor mechanism in the REM sleep deprivation-induced increase in swimming activity in the forced swimming test.

Effects of monoamine synthesis inhibitors and dopamine antagonists on rapid eye movement sleep (REMs) deprivation treatment-induced increase in swimming activity were examined. Mice were deprived of REMs for 48 h by a small pedestal method. Swimming activity in REMs-deprived mice was significantly higher than those in group-housed or socially isolated animals used as the control. dl-alpha-Methyl- p-tyrosine methyl ester HCl (250 mg/kg, IP) decreased the swimming activity in REMs-deprived mice, whereas neither disulfiram (400 mg/kg, SC), a noradrenaline synthesis inhibitor, nor dl-p-chlorophenylalanine methyl ester HCl (300 mg/kg, IP) changed it. (+)-SCH23390 HCl (30 and 100 micrograms/kg, IP), a selective dopamine D1 antagonist, did not affect the activity in REMs-deprived mice. (+/-)-Sulpiride (12.5 and 25 mg/kg, IP), a selective dopamine D2 antagonist, dose-dependently decreased swimming activity in REMs-deprived mice, while it did not significantly change the swimming activity in the control animals. These results suggest that REMs deprivation treatment-induced increase in swimming activity is mainly due to the functional changes in the dopaminergic system rather than the noradrenergic or serotonergic system, and that dopamine D2 but not D1 receptor mechanism is involved in the increase in swimming activity in REMs-deprived animals.

Animals↗

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↗

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↗

Swimming lessons, swimming ability, and the risk of drowning.

Drowning is a leading cause of injury related death in many countries. Strategies to prevent these deaths depend upon characteristics of the victim and the specific circumstances surrounding the event. One preventive strategy that may be beneficial for persons of all ages and under nearly all circumstances is increased swimming ability, through some form of swimming instruction. However, a clear protective relationship between increased swimming ability and the risk of drowning has never been demonstrated. Studies focused on children, suggest that swimming ability may confer some protection, although the data are far from conclusive. This paper (1) reviews the current evidence regarding the relationship between swimming ability, swimming lessons and the risk of drowning, (2) reviews the past and present recommendations for swimming instruction and (3) outlines future research needs.

Adolescent↗

Bilateral inter-arm coordination in freestyle swimming: effect of skill level and swimming speed.

The aim of this study was to examine the influence of level of skill and swimming speed on inter-limb coordination of freestyle swimming movements. Five elite (2 males, 3 females; age 18.9+/-1.0 years, height 1.71+/-0.04 m, body mass 62.1+/-7.0 kg) and seven novice (age 22.0+/-2.0 years, height 1.77+/-0.04 m, body mass 74.8+/-9.0 kg) swimmers swam a sprint and a self-paced 25 m freestyle trial. The swimming trials were recorded by four digital cameras operating at 50 Hz. The digitized frames underwent a three-dimensional direct linear transformation to yield the three-dimensional endpoint kinematic trajectories. The spatio-temporal relationship between the upper limbs was quantified by means of the peak amplitude and time lag of the cross-correlation function between the right and left arm's endpoint trajectories. A strong anti-phase coupling between the two arms, as confirmed by peak amplitudes greater than 0.8, was noted for both groups and swimming speeds. Significantly higher (P<0.05) peak amplitudes were observed for the sprint compared with self-paced swimming. No significant differences in the strength of inter-limb coupling were noted between the elite and novice swimmers (P>0.05). Time lags were very close to 0 ms and did not differ between groups or swimming speeds. We conclude that in freestyle swimming, the intrinsic anti-phase (180 degrees phase difference) inter-limb relationship is strongly preserved despite the physically powerful environmental influence of the water and this "preferred" pattern is not affected by level of skill. In contrast, increasing movement speed results in stronger inter-limb coupling that is closer to the anti-phase inter-limb relationship.

Acceleration↗