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PubMed2000

The effects of drafting on stroking variations during swimming in elite male triathletes.

The aim of this study was to determine the effects of drafting behind another swimmer on the metabolic response and stroke characteristics. Six highly trained male triathletes performed two maximal 400-m swims, one in a drafting (D) and one in a non-drafting condition (ND). Their metabolic response was assessed by measuring the oxygen uptake (VO2) and the blood lactate concentration at the end of each 400 m. Swimming velocity, stroke frequency, stroke length, and stroke index (velocity multiplied by stroke length) were recorded every 50 m. In the D and ND conditions, there was no difference in VO2 [66.7 (1.7) ml x kg(-1) x min(-1) vs 65.6 (1.2) ml x kg(-1) min(-1) respectively], however, the lactate concentrations were lower in D than in ND [9.6 (0.9) mM vs 10.8 (0.9) mM, respectively, P < 0.01]. In D, the performance [1.39 (0.02) m x s(-1) vs 1.34 (0.02) m x s(-1), respectively, P < 0.01] and the stroking parameters (i.e., stroke length and stroke index) increased significantly, while the stroke frequency remain unchanged. In D, a stable pace was maintained, while in ND, velocity decreased significantly throughout the 400 m. In D, the performance gains were related to the 400-m D velocity (r = 0.78, P < 0.05), and to the body fat mass (BFM, r = 0.99, P < 0.01). The stroke index in D was also related to BFM (r = 0.78, P < 0.05). Faster and leaner swimmers achieved greater performance gains and stroke index when drafting. Thus, drafting during swimming increases the performance and contributes to the maintenance of stable stroking parameters such as stroke frequency and stroke length during a 400-m swim.

Adult↗
PubMed1997

Effect of intensive swimming training on lung volumes, airway resistance and on the maximal expiratory flow-volume relationship in prepubertal girls.

The aim of the present study was to analyse the effect of 1 year of intensive swimming training on lung volumes, airway resistance and on the flow-volume relationship in prepubertal girls. Five girls [9.3 (0.5) years old] performing vigorous swimming training for 12 h a week were compared with a control group of 11 girls [9.3 (0.5) years old] who participated in various sport activities for 2 h per week. Static lung volumes, maximal expiratory flows (MEF) at 75, 50 and 25% of vital capacity, 1-s forced expiratory volume (FEV1.0) and airway resistance (R(aw)) were measured by means of conventional body plethysmograph techniques. Prior to the training period there were no significant differences between the two groups for any of the parameters studied. Moreover, for both groups, all parameters were within the normal range for children of the corresponding age. After 1 year of training, vital capacity (VC), total lung capacity (TLC) and functional residual capacity (FRC) were larger (P < 0.05) in the girl swimmers than in the control group, while physical development in terms of height and weight was similar. FEV1.0 (P < 0.01), MEF25, MEF50 (P < 0.05) and MEF75 as well as the ratio MEF50/TLC (P < 0.05) had increased in the girl swimmers but were unchanged in the control group. R(aw) tended to be lower in the girl swimmers and higher in the control group. The results indicate that intensive swimming training prepuberty enhances static and dynamic lung volumes and improves the conductive properties of both the large and the small airways. As to the causative mechanism, it can be speculated that at prepuberty intensive swimming training promotes isotropic lung growth by harmonizing the development of the airways and of alveolar lung spaces.

Airway Resistance↗
PubMed2000

Factors limiting cold-water swimming distance while wearing personal floatation devices.

The influence of body adiposity, arm skinfold thickness, aerobic capacity, and cooling rate were studied in a mock survival swimming situation conducted in water at around 14 degrees C. Seventeen adult participants wore personal floatation devices on top of seasonal clothing and were asked to swim as far as they could, as if attempting to reach shore following an accidental immersion in cold water. Triceps and patellar skinfold thickness showed a significant correlation with distance covered (r = 0.70 and 0.56, respectively), while abdominal skinfold and percent body fat showed no significant correlation. Maximum oxygen consumption (VO2max) was not significantly related to distance covered. There was a negative correlation between body cooling rate during the swimming period and distance covered. A multiple stepwise regression analysis, however, indicated that the only significant contributor to variance in the distance covered was the triceps skinfold thickness (r2 = 0.49). It was concluded that for a healthy subject accidentally immersed in cold water, triceps skinfold thickness is a stronger predictor of the swimming distance covered than body adiposity, VO2max, or the drop in core temperature.

Abdomen↗
PubMed2006

Combined intervention of dietary soybean proteins and swim training: effects on bone metabolism in ovariectomized rats.

Soybean proteins, a rich source of isoflavones, taken immediately after an ovariectomy prevent bone loss in rats. Exercise-induced stimuli are essential for bone growth. Few studies exist about the combined effects of swim training and soybean protein supplementation on bone metabolism. So, the purpose of this study was to investigate, in 48 female Sprague-Dawley rats (12 weeks old) the effects of an 8-week swim-training regimen (1 h/day, 5 days/week) and dietary soybean proteins (200 g/kg diet) on bone metabolism. Rats were randomly assigned to four groups: (1) ovariectomized fed with a semisynthetic control diet; (2) ovariectomized fed with a soybean protein-enriched semisynthetic diet; (3) ovariectomized trained to exercise and fed with control diet; (4) ovariectomized trained to exercise and fed with a soybean protein diet. Following the treatment period, body weight gain was identical in the four groups. Soybean protein supplementation increased bone calcium content, and reduced plasma osteocalcin values, without significant modification of calcium balance and net calcium absorption. Swim training enhanced plasma and bone calcium content and calcium balance and net calcium absorption. It did not modify either plasma osteocalcin values or urinary deoxypyridinoline excretion. Both exercise and soybean protein intake increased plasma on bone calcium without modifying net calcium absorption or bone markers. In conclusion, we demonstrated, in ovariectomized rats, that swimming exercise and dietary supplementation with soy proteins do not have synergistic effects on calcium metabolism and bone markers.

Amino Acids↗
PubMed1981

Induction of swimming in the high spinal stingray by L-DOPA.

Stingrays with high spinal transections, which do not spontaneously locomote, can be induced to swim by intravenous injection of L-DOPA. The L-DOPA-induced swim of the spinal animal is associated with patterns of EMG activity that appear similar to those of the spontaneous swim of the decerebrate preparation. However, in contrast to the decerebrate condition, the L-DOPA-induced cycles of swimming are slower and less vigorous. Furthermore, secondary periodicites and altered intersegmental timing relationships are also evident.

Animals↗
PubMed1981

Increased GABA binding in mouse brain following acute swim stress.

Acute swim stress of mice produces increases in the density of high and low affinity binding sites in the brain for the inhibitory neurotransmitter gamma-aminobutyric acid (GABA), together with analgesia as measured by an increase in tail flick latency. Apparent tolerance develops in repeated swimming with analgesia and GABA binding returning towards control levels. The time course of analgesia and increases GABA binding following a single swim are also similar. Acute swim stress does not alter diazepam binding. GABA systems may be important in analgesia and in responses to environmental stress.

Acute Disease↗
PubMed1986

Correlation between pentobarbital suppressed cerebellar cyclic GMP and performance of a swimming task.

Ovariectomized female Sprague-Dawley rats were trained to swim a 2.5 m course. On the day of the experiment the time required for each animal to swim the course was determined, and then the animal received either saline or one of 4 dosages of sodium pentobarbital, intravenously. Four minutes after treatment the animal's swim time was again recorded, and the animal was immediately killed by microwave irradiation. The cerebellum was collected for subsequent determination of cyclic guanosine monophosphate (cGMP). Pentobarbital caused a dosage-dependent suppression of cerebellar cGMP which was highly correlated with a drug-induced increase in the time required to swim 2.5 m. These data provide the first evidence of a correlation between a barbiturate-induced effect on a neurochemical parameter and impaired performance of a learned behavior.

Animals↗
PubMed1988

Lack of effect of adrenal denervation on analgesia elicited by continuous and intermittent cold water swim in the rat.

The present experiment was conducted to determine if continuous and/or intermittent cold water swim analgesia is dependent upon a factor released from the adrenal medullae. Male Sprague-Dawley rats (300-350 g) underwent either bilateral adrenal denervation or sham surgery and two weeks later were exposed to continuous (3.5 m) or intermittent (10 s in, 10 s out for 6 min) swim in water at 4 degrees C. Adrenal denervation failed to affect either intermittent or continuous cold water swim analgesia. It was concluded that both types of cold water swim analgesia are independent of adrenal medullary function.

Adrenal Medulla↗
PubMed1983

Serum creatine kinase and CK-MB isoenzyme responses to acute and prolonged swimming in trained athletes.

Six highly-trained male swimmers completed a maximum work capacity tethered swim and a 1-h continuous tethered swim at approximately 70% VO2max in order to evaluate total serum creatine kinase and CK-MB isoenzyme changes. Venous blood obtained before, 5 min post-, 6 h post-, and 24 h post-exercise was analyzed for total serum CK (kinetic UV method, normal = less than 100 U/l) and CK-MB isoenzyme (quantitative electrophoretic technique, normal = less than 5 U/l). VO2max averaged 4.59 +/- 0.28 l/min, with a mean total work time of 24.5 min to achieve maximum capacity. Mean resting total CK was 100.5 +/- 15.8 U/l. Compared to rest, neither swim bout produced a significant (p greater than 0.05) elevation in mean total creatine kinase. No CK-MB isoenzyme was observed in any post-exercise blood sample. Swimming, performed by highly-trained swimmers at high levels of intensity or for prolonged durations, may not impose sufficient degrees of trauma producing muscular stress. Therefore, the structural integrity of the cell membrane is maintained and the loss of intracellular creatine kinase to the bloodstream prevented.

Adolescent↗
PubMed1993

Effects of diazepam and desipramine in the forced swimming test: influence of previous experience with the situation.

The effects of desipramine and diazepam on the behavior of rats in the forced swimming test were studied. Desipramine significantly enhanced struggling behavior, the intensity of its effect being greater in rats previously exposed to the forced swimming test for 1 or 4 days before drug administration. The effect of desipramine on immobility was significantly only in rats previously exposed to the test. Acute diazepam administration did not modify the behavior of rats in the test. Chronic administration (6 days) of two different doses of diazepam did not alter the behavior of rats in the forced swimming test, but significantly decreased the defecation rate, suggesting that the drug was effective as an anxiolytic. The present results suggest that the behavior of rats in the forced swimming test might be related to mood states rather than to fear/anxiety and that efficacy of the test to detect antidepressant activity might be enhanced by repeated exposure of the rats to the situation.

Animals↗
PubMed1995

Co-released adrenaline markedly facilitates noradrenaline overflow through prejunctional beta 2-adrenoceptors during swimming exercise.

The effect of intravenously applied (-)-adrenaline, taken up by and released from sympathetic nerves, on swimming exercise-induced noradrenaline overflow in permanently cannulated adrenal demedullated rats was studied. Adrenaline (100 ng/min) was infused for 2 h, during which a plasma concentration of 500 pg/ml (approximately 2.5 nM) was reached. One hour later plasma adrenaline had returned to undetectable levels. During swimming, adrenaline was released into the plasma in concentrations up to 133 pg/ml and the noradrenaline concentration was markedly enhanced as well. The total catecholamine increase amounted to 178% of control (saline infusion) in the first 3 min of swimming and 165% for the whole 20 min. Cocaine (2.5 mg/kg plus 0.05 mg/kg/min), infused together with adrenaline and continued throughout the experiment, prevented the exercise-induced release of adrenaline and no increase in plasma noradrenaline concentration was observed. Yohimbine (0.25 mg/kg) strongly further enhanced the exercise-induced overflow of both noradrenaline and adrenaline. This further increase was completely blocked by the selective beta 2-adrenoceptor antagonist ICI 118,551 ((+/-)-1-[(2,3-dihydro-7-methyl-1H-inden-4-yl)oxy]-3-[(1-methyleth yl) amino]-2-butanol) (1.0 mg/kg). These results demonstrate that adrenaline can be taken up by sympathetic nerve endings through cocaine-sensitive uptake carriers and is released from these nerves during swimming exercise. Neuronally released adrenaline markedly enhances exercise-induced catecholamine overflow through activation of prejunctional beta 2-adrenoceptors.

Adrenergic beta-Antagonists↗
PubMed1995

Conservation of energy in competitive swimming.

Energy conservation in swimming is formulated in terms of four functions of the swim speed v: the consumed power K, the mechanical power P used for horizontal propulsion, the remaining expended mechanical power N, and the thermal power loss H. K is well-known (from VO2) and P = FDv, where the drag force FD is not known with certainty but represents a small effect. Estimates of the nonpropulsive components of a swimmer's body motions reveal that N is small, less than 3 watts per kg of body mass. H is estimated by using the theory of convective heat transfer to express the heat loss in terms of the difference between the swimmer's skin temperature and the water temperature. This temperature difference was measured for the NYU men's swim team and found to be 0.033 K per kg of body mass, giving H approximately 34 W kg-1. The results are seen to be in good agreement with the asymptotic (large swim time tf) form of energy conservation. The further requirement that energy conservation is valid to order 1/tf, and use of the 1993 world record race times, is shown to imply that the initial energy available in a swimmer's body is 963 +/- 231 joules per kg of body mass.

Biomechanical Phenomena↗
PubMed1992

Suppressive effect of coenzyme Q10 on phospholipase A2 activation in cardiac cells after prolonged swimming.

Phospholipase A2 (PLA2) activity is elevated in cardiac microsomal fractions and phospholipids (PL) are much reduced in both the cardiac mitochondria and microsomal fractions from rats subjected to prolonged swimming. Preadministration of coenzyme Q10 (CoQ10 i.v. 30 mg/kg) significantly suppressed these changes. Two groups of 8-week-old male Wistar rats were trained to swim, receiving 30 min of training for 4 days. On the fifth day they were given an intravenous injection of either 30 mg/kg CoQ10 in saline or 1 ml saline. Thirty minutes later they began to swim for 3 hours carrying a weight representing 3% of body weight. On completion of the swim they were sacrified by instantaneous decapitation, and cardiac mitochondria were isolated. Mitochondria were also prepared from saline injected, unexercised control rats. Phosphatidylethanolamine (PE) and phosphatidylcholine (PC) concentrations were measured with HPLC and PLA2 activity was assayed fluorometrically. The mitochondrial concentrations (means +/- SEM, n = 6) of PE and PC were respectively 126 +/- 22 and 140 +/- 22 nmol/mg protein in the exercise-CoQ10 group against 66 +/- 4 and 50 +/- 10 nmol/mg protein in the exercise-saline group. The specific PLA2 activities (expressed as nmol degraded dipyrene phosphorylethanolamine substrate/hr/mg protein) in the microsomes was 0.20 +/- 0.02 in the exercise-CoQ10 group against 0.30 +/- 0.02 in the exercise-saline group. These results suggest CoQ10 has a protective effect against an excessive reduction in mitochondrial membrane phospholipids during prolonged exercise.

Animals↗
PubMed1996

Cold swim stress leads to enhanced splenocyte responsiveness to concanavalin A, decreased serum testosterone, and increased serum corticosterone, glucose, and protein.

This study extends previous observations of the conditions under which enhancement of lymphocyte activity occurs following cold swim stress and presents a possible explanation for the enhancement observed. Eight- to twelve-week old male Sprague-Dawley rats swam for 10 minutes daily for one, three, or five days in cold water at 15 degrees C and were killed 0, 30, or 240 minutes following the last swim. Apparatus control animals were placed into an empty swim tank for 10 minutes and then returned to their home cages. Home cage control animals were not manipulated experimentally at all. Splenocyte but not thymocyte responses to concanavalim A were significantly enhanced after one, three, and five days of stress. This enhancement was seen after 0, 30, and 240 minutes of recovery and also in the apparatus controls! The number of splenocytes did not change significantly, but thymocyte number declined following the swims. The blood displayed no changes in leukocyte percents. Serum corticosterone levels were significantly higher and serum testosterone levels were significantly lower after one, three, and five days of stress. The drop in testosterone levels may have released the lymphocytes from inhibition by this hormone, resulting in increased responsiveness. There were significant elevations in levels of blood glucose and protein following one, three, and five days of stress sessions, correlated with the increases in serum corticosterone.

Animals↗
PubMed1986

Infusion of adrenergic receptor agonists and antagonists into the locus coeruleus and ventricular system of the brain. Effects on swim-motivated and spontaneous motor activity.

These studies examined how pharmacological stimulation and blockade of alpha receptors would affect active motor behavior in rats. In experiment I, alpha-2 receptor antagonists (piperoxane, yohimbine) and agonists [clonidine, norepinephrine (NE)] were infused into various locations in the ventricular system of the brain, including the locus coeruleus region, and motor activity was measured. Activity was measured principally in a swim test but spontaneous (ambulatory) activity was also recorded while drugs were being infused. When infused into the locus coeruleus region, small doses of the antagonists piperoxane and yohimbine depressed activity in the swim test while infusion of the agonists clonidine and NE had the opposite effect of stimulating activity. These effects were highly specific to the region of the locus coeruleus, since infusions of these drugs into other nearby locations in the ventricular system or use of larger doses had different, often opposite effects. This was especially true of clonidine and NE which profoundly depressed activity when infused posterior to the locus coeruleus, particularly over the dorsal vagal complex. Infusion of small doses of these drugs into the lateral ventricle had effects similar to infusion into the locus coeruleus region, though less pronounced. Changes in spontaneous motor activity were also observed, but this measure differentiated the groups less well than did the swim test. In experiment II, the predominantly postsynaptic receptor agonists isoproterenol (beta agonist) and phenylephrine (alpha-1 agonist) were infused into the ventricular system. Since infusions of piperoxane and yohimbine into the locus coeruleus that decreased activity in experiment I increase the release of NE by blocking alpha-2 inhibitory receptors on cell bodies and dendrites of the locus coeruleus, experiment II tested whether ventricular infusion of predominantly postsynaptic receptor agonists would also decrease activity in the swim test. Both isoproterenol and phenylephrine produced this effect, but did so selectively with respect to dose and location of infusion in the ventricular system. These findings are consistent with recent results relating to the mechanism that underlies stress-induced depression of active behavior.

Adrenergic alpha-Agonists↗
PubMed1984

Swimming immobility of REM sleep deprived rats reared in different environments.

This study tested the hypothesis that environmental rearing treatments which alter the REM sleep levels of rats affect swimming immobility, an adaptive, REM sleep sensitive behavior. At weaning, 72 female Sprague-Dawley rats were maintained in either an enriched, an impoverished, or a social control environment for 32-33 days. They were then placed in either a REM sleep depriving platform-in-water condition or in one of two control conditions (large platform or dry control) for 4 days before being scored for swimming immobility during a 10-min swimming test. A 3 (environments) X 3 (platforms) ANOVA revealed a main effect for environments, F(2,63) = 5.20, p less than 0.01. Enriched rats exhibited a behavioral advantage over impoverished rats under the large platform control condition, F(1,63) = 6.58, p less than 0.025, and under the dry control condition, F(1,63) = 6.14, p less than 0.025. However, under the REM depriving condition, their behavioral advantage was virtually eliminated, F(1,63), p less than 1. The conclusion that the REM sleep levels of the rat groups probably determined their swimming immobility scores is discussed.

Adaptation, Physiological↗
PubMed1988

The modified forced-swim test in rats: influence of rope- or straw-suspension on climbing behavior.

We modified Porsolt's forced-swim test by suspending ropes or straws above the water in order to investigate a possible relationship between immobility and perceived escape responses from water. In this modified test, it was demonstrated clearly that rats reduced their duration of immobility and attempted to climb up the suspended ropes or straws. Most rats which had remained immobile during a 5-min test period in the forced-swim test, exhibited such climbing responses within 5-10 min of rope-suspension. Despite the suspension of ropes, however, some rats showed immobile postures and did not respond to the rope. On the other hand, straws were used in order to produce sliding and prevent climbing when the animals attempted to climb. There were no differences in immobility during either rope- or straw-suspension. It seems that the climbing behavior displayed by forced-swimming rats is due to a "pseudo-escape" effect produced by the suspension of an object above the water. The present findings were interpreted as further evidence for the notion that immobility in forced-swimming rats does not necessarily imply "behavioral despair," but rather an emotional reaction to an inescapable stressor.

Animals↗
PubMed1990

Effect of swimming to exhaustion, at low temperatures, on serum Zn, Cu, Mg and Ca in rats.

In order to study the response of plasma trace minerals during exercise in cold water at varying temperatures, three groups of ten male Wistar rats each were forced to swim until exhaustion in water at different constant temperatures (10, 20 and 32 degrees C), while another 3 groups were kept at rest in water at the same temperatures and another group at rest out of the water, at room temperature (21 degrees C). Rectal temperature (RT) was measured before and after the exercise. Samples of arterial blood were obtained under anaesthesia (pentobarbital) from the abdominal aorta after the exercise, and serum concentrations of Cu, Zn, Mg and Ca were determined by flame atomic absorption spectrophotometry (FAAS). The swimming time (ST) decreased in cold water, the values obtained at 10 and 20 degrees C being 3.3% and 8.5%, respectively, of those observed at 32 degrees C. The RT of the animals swimming at 32 degrees C was 32.5 +/- 1.8 degrees C (mean +/- SD) and fell to 25.0 +/- 2.0 and to 19.1 +/- 1.5 degrees C in those swimming, respectively, at 20 and 10 degrees C. The concentrations of Mg, Cu and Ca were significantly higher (+50%, +36% and +7%, respectively) in animals subjected to exercise with respect to the control groups in water, although there were no differences among the three groups. On the contrary, Zn rose progressively with the increase of WT (+32% at 10 degrees C, +60% at 20 degrees C and +76% at 32 degrees C).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗