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PubMed2006

The consequences of swim, cycle, and run performance on overall result in elite olympic distance triathlon.

This study examined the consequences of performance in swim, cycle, and run phases on overall race finish in an elite "draft legal" Olympic distance (OD) triathlon. The subjects were 24 male athletes grouped by rank order into the top 50 % (n = 12) and bottom 50 % (n = 12) of the race population. Swimming velocity (m x s (-1)), cycling speed (km x h (-1)), and running velocity (m x s (-1)) were measured at regular intervals using a global positioning system, chip timing system, and video analysis. Actual rank after each stage and overall was obtained from the race results and video analysis. The top 50 % athletes overall swam faster over the first 400 m of the swim phase (p > 0.05). Their swim ranking was lower (p < 0.01) than the bottom 50 % athletes after this stage. There were no significant differences in actual race position between the groups after the cycle. However, the bottom 50 % athletes after the swim stage cycled faster (p < 0.01) at 13.4 km of the cycle. Speed at 13.4 km of the cycle stage was inversely correlated (r = 0.60, p < 0.01) to running performance. Performance (rank and velocity) in the running stage was highly correlated with overall race result (r = 0.86 and - 0.53, respectively, both p > 0.01). It appears that inferior swimming performance can result in a tactic that involves greater work in the initial stages of the cycle stage of elite OD racing, and may influence subsequent running performance.

Analysis of Variance↗
PubMed2006

Evaluation of the energy expenditure in competitive swimming strokes.

The purpose of this study was to measure and compare the total energy expenditure of the four competitive swimming strokes. Twenty-six swimmers of international level were submitted to an incremental set of 200-m swims (5 swimmers at Breaststroke, 5 swimmers at Backstroke, 4 swimmers at Butterfly and 12 swimmers at Front Crawl). The starting velocity was approximately 0.3 m x s (-1) less than a swimmer's best performance and thereafter increased by 0.05 m x s (-1) after each swim until exhaustion. Cardio-pulmonary and gas exchange parameters were measured breath-by-breath (BxB) for each swim to analyze oxygen consumption (VO2) and other energetic parameters by portable metabolic cart (K4b(2), Cosmed, Rome, Italy). A respiratory snorkel and valve system with low hydrodynamic resistance was used to measure pulmonary ventilation and to collect breathing air samples. Blood samples from the ear lobe were collected before and after each swim to analyze blood lactate concentration (YSI 1500 L, Yellow Springs, Ohio, USA). Total energy expenditure (E(tot)), was calculated for each 200-m stage. E (tot) differed significantly between the strokes at all selected velocities. At the velocity of 1.0 m x s (-1) and of 1.2 m x s (-1) the E(tot) was significantly higher in Breaststroke than in Backstroke, in Breaststroke than in Freestyle and in Butterfly than in Freestyle. At the velocity of 1.4 m x s (-1), the E(tot) was significantly higher in Breaststroke than in Backstroke, in Backstroke than in Freestyle, in Breaststroke than in Freestyle and in Butterfly than in Freestyle. At the velocity of 1.6 m x s (-1), the E(tot) was significantly higher in Breaststroke and in Butterfly than in Freestyle. As a conclusion, E(tot) of well-trained competitive swimmers was measured over a large range of velocities utilising a new BxB technique. Freestyle was shown to be the most economic among the competitive swimming strokes, followed by the Backstroke, the Butterfly and the Breaststroke.

Analysis of Variance↗
PubMed1992

Bioenergetic characteristics of swimmers determined during an arm-ergometer test and during swimming.

The maximal oxygen uptake (VO2max) of 13 swimmers was determined by an arm-ergometer test (direct method) and estimated from a maximal multistage swimming test (indirect method) (23). A test-retest of the progressive swimming exercise showed that there were no significant differences from one test to the other and that there were significant correlations between the principal parameters: arm stroke index: 0.73, maximal aerobic swimming velocity: 0.94, VO2max: 0.95, p less than 0.01. Therefore, for swimmers of average ability, the reproducibility of this test has been proved. A significant difference (p less than 0.001) was observed between the two tests for VO2max: arm-ergometer test (VO2max arms): 2.4 +/- 0.5 l.min-1, swimming test (VO2max ST): 3.2 +/- 0.7 l.min-1, p less than 0.01. This difference appeared to be linked to the use of a greater muscle mass (arms and legs) during swimming. A significant correlation (r = 0.73, p less than 0.01) was obtained between VO2max (l.min-1) by using both the direct and indirect exercises as methods of measurement. However, the level of r did not permit the prediction of one parameter from the other. Significant correlations were obtained between VO2max and performances over 200 and 400 m free style regardless of the methodology used (VO2max arm, VO2max ST). Moreover, only VO2max (arm, ST) emerged as a variable accounting for swimming performance from a step-wise multiple regression analysis, in which biometric and bioenergetic parameters were taken into account.

Adolescent↗
PubMed1991

Relationship between upper body anaerobic power and freestyle swimming performance.

The purpose of this study was to examine the role of upper body anaerobic power, as measured by the Wingate Anaerobic Arm Test (WAAT), in 50-m sprint swim performance. Thirty competitive age-group swimmers (14 males and 16 females) participated in this investigation. Subjects had been training daily for 5 months prior to the study, swimming an average of 6,000 m.d-1, 6 d.wk-1. Swimmers performed a WAAT and a 50-m time-trial. Peak power (PP), mean power (MP) and fatigue index (FI) were determined for the WAAT. Subjects also reported their current competition performances for all distances up to 400 m. Significant relationships were obtained between swim speed over 50 m (S50) and PP (r = 0.82, p less than 0.001), S50 and MP (r = 0.83, p less than 0.001), and S50 and FI (r = 0.41, p less than 0.05). PP and MP showed significant but generally decreasing correlations with swim speed as distance increased. Substantial relationships (r = 0.74-0.96, p less than 0.001) were found between S50 and swim speeds over distances up to and including 400 m. This study shows a strong relationship exists between upper body anaerobic power, as measured by the WAAT, and performance in both sprint and longer distance (400 m) swim events. The WAAT may serve as a useful tool for coaches to objectively evaluate and monitor the upper body anaerobic power of competitive swimmers.

Acceleration↗
PubMed1989

Hormonal changes after supine posture, immersion, and swimming.

This study was undertaken to evaluate the effects of the supine posture, immersion, and swimming on hormones involved in the regulation of hydrosaline equilibrium. Plasma levels of atrial natriuretic peptide (ANP), arginine vasopressin (AVP), plasma renin activity (PRA), and aldosterone (ALDO) were measured by radioimmunoassay in eight untrained young subjects (five males and three females). Blood samples were collected on different days: control morning samples in a relaxed standing posture before each test; after 20 min in a supine position; after 20 min of horizontal immersion in water at 28 degrees C; after 20 min of backstroke swimming (speed about 1 m/s). No changes occurred in AVP levels after each test. ALDO and PRA increased significantly only after swimming and were directly correlated. ANP increased significantly after immersion, but no further increase was observed after swimming. The hematocrit, which increased after swimming, was inversely correlated with ANP levels in the post-exercise samples. These data show that while ALDO and PRA increase only in response to swimming, even at moderate intensity, ANP probably requires more prolonged and intense exercise to reach a significantly higher level than in immersion.

Adult↗
PubMedDate not supplied

Fresh water swimming as a risk factor for otitis externa: a case-control study.

A case-control study was conducted in which the amount and sites (fresh-water lakes and rivers, chlorinated pools, or the ocean) of recent swimming by 105 patients with otitis externa were compared with that of 239 controls. Swimming during the week prior to the visit was strongly associated with otitis externa. When the 80 cases and 127 controls with a history of recent swimming were compared, otitis externa was positively associated with the amount of swimming during the preceding week. Otitis externa was also positively associated with swimming in fresh water compared with ocean or pool swimming with the magnitude of this association being more pronounced at higher levels of exposure.

Adult↗
PubMed2002

Accuracy of pacing during breaststroke swimming using a novel pacing device, the Aquapacer.

Generally, swimmers pace themselves using their own judgement and the poolside clock during swimming training, fitness testing protocols or scientific investigation. The Aquapacer is a new pacing device that can be used to pace the swimming speed or stroke rate of the swimmer. The aims of this study were to determine if breaststroke swimmers could pace accurately during submaximal swimming using a poolside clock (Study 1) and the Aquapacer (Study 2), at swimming speeds at, just above and just below maximal 200 m time-trial speeds (using the Aquapacer, Study 3) and under three different race pacing conditions (using the Aquapacer, Study 4). Between 8 and 15 male national or club standard 200 m breaststroke swimmers participated in each of the studies. The swimmers in Study 2, despite being less well trained than the swimmers in Study 1 and part of a more heterogeneous group in terms of swimming performance, repeatedly demonstrated less random error in pacing, suggesting that the Aquapacer may be preferable to the poolside clock when swimmers are being required to pace accurately. The Aquapacer also enabled swimmers to pace accurately at race-specific swimming speeds (until fatigue precluded them from holding pace) (Study 3), and through a change in pace at race-specific speeds (Study 4), which suggests that it may be of use in entraining racing strategies.

Adult↗
PubMed1986

Measurement of active drag during crawl arm stroke swimming.

In order to measure active drag during front crawl swimming a system has been designed, built and tested. A tube (23 m long) with grips is fixed under the water surface and the swimmer crawls on this. At one end of the tube, a force transducer is attached to the wall of the swimming pool. It measures the momentary effective propulsive forces of the hands. During the measurements the subjects' legs are fixed together and supported by a buoy. After filtering and digitizing the electrical force signal, the mean propulsive force over one lane at constant speeds (ranging from about 1 to 2 m s-1) was calculated. The regression equation of the force on the speed turned out to be almost quadratic. At a mean speed of 1.55 m s-1 the mean force was 66.3 N. The accuracy of this force measured on one subject at different days was 4.1 N. The observed force, which is equal to the mean drag force, fits remarkably well with passive drag force values as well as with values calculated for propulsive forces during actual swimming reported in the literature. The use of the system does not interfere to any large extent with normal front crawl swimming; this conclusion is based on results of observations of film by skilled swim coaches. It was concluded that the system provides a good method of studying active drag and its relation to anthropometric variables and swimming technique.

Biomechanical Phenomena↗
PubMed1989

Urea production during prolonged swimming.

Male interscholastic swimmers (n = 8) completed a 4572 m training swim in in 62 +/- 1.1 min (means +/- S.E.) with terminal heart rate and blood lactate of 152 +/- 6 beats min-1 and 6.9 +/- 0.89 mM, respectively. Sweat rate (0.48 +/- 0.095 l. h-1) was lower than similar intensity cycling (1.5 +/- 0.13 l. h-1) or running (1.1 +/- 0.14 l. h-1). Post-swim serum urea N (11.6 +/- 0.71 mM) was elevated (P less than 0.05) vs pre-swim (4.6 +/- 0.39 mM). Post-swim urine volume (860 +/- 75 ml 24 h-1) was reduced (P less than 0.07) and resulted in an elevated (P less than 0.05), but delayed (24-84 h), post-exercise urea N excretion. Although the reduced urine and sweat production during the swim undoubtedly contributed to the elevated serum urea, there must be another explanation because together they could only account for 38% of the observed increase. On the basis of the magnitude of serum urea increase, it appears that the swim caused an increase in urea production (amino acid oxidation). The failure to observe larger increases in urinary urea during recovery indicates that either urea excretion following exercise continues for prolonged periods of time (greater than 48 h) or another significant mode of nitrogen excretion exists.

Adolescent↗
PubMedDate not supplied

Energetic costs of surface swimming and diving of birds.

The energetic costs of swimming at the surface (swimming) and swimming underwater (diving) are compared in tufted ducks (Aythya fuligula) and three species of penguins, the gentoo (Pygoscelis papua), the king (Aptenodytes patagonicus), and the emperor (Aythya forsteri). Ducks swim on the surface and use their webbed feet as paddles, whereas penguins tend to swim just below the surface and use their flippers as hydrofoils, the latter being much more efficient. Penguins are more streamlined in shape. Thus, the amount of energy required to transport a given mass of bird a given distance (known as the cost of transport) is some two to three times greater in ducks than in penguins. Ducks are also very buoyant, and overcoming the force of buoyancy accounts for 60% and 85% of the cost of descent and remaining on the bottom, respectively, in these birds. The energy cost of a tufted duck diving to about 1.7 m is similar to that when it is swimming at its maximum sustainable speed at the surface (i.e., approximately 3.5 times the value when resting on water). Nonetheless, because of the relatively short duration of its dives, the tufted duck dives well within its calculated aerobic dive limit (cADL, usable O(2) stores per rate of O(2) usage when underwater). However, these three species of penguins have maximum dive durations ranging from 5 min to almost 16 min and maximum dive depths from 155 to 530 m. When these birds dive, they have to metabolise at no more than when resting in water in order for cADL to encompass the duration of most of their natural dives. In gentoo and king penguins, there is a fall in abdominal temperature during bouts of diving; this may reduce the oxygen requirements in the abdominal region, thus enabling dive duration to be extended further than would otherwise be the case.

Aerobiosis↗
PubMed1996

Energetics of underwater swimming with SCUBA.

Underwater swimming has unique features of breathing apparatus (SCUBA), thermal protective gear, and fins. The energy cost of underwater swimming is determined by the drag while swimming and the net mechanical efficiency. These are influenced by the cross-sectional area of the diver and gear and the frequency of the leg kick. The speeds that divers can achieve are relatively low, thus the VO(2) increases linearly with values of VO(2)*d(-1) of 30-50 l*km(-1)for women and men, respectively. Diving experience had little effect on VO(2) for women; however, male divers with experience had lower VO(2) than beginners. The location and density of the gear can alter the diver's attitude in the water and increase the energy cost of swimming by 30 percent at slow speeds. The type of fin used has an effect on the depth and frequency of the kick, thus on drag and efficiency, with a range of VO(2) from 25 to 50 l*km(-1). A large flexible fin had the lowest energy cost and a large rigid fin the highest. Adding extra air tanks or a dry suit increased the cost of swimming by 25 percent. The energy cost of underwater swimming is influenced by gender, gear and its placement, fin type, and experience of the diver.

Diving↗
PubMed2007

Lithium's effect in forced-swim test is blood level dependent but not dependent on weight loss.

The effects of lithium in models of depression are often inconsistent. We aimed to replicate a regimen that induces robust antidepressant effects in the forced-swim test. Mice were treated with three different doses of lithium chloride (LiCl) 0.25, 0.4 or 0.5% in food and the forced-swim test or open field test was performed on day 15. We yoked control mice to food deprivation to test whether lithium-induced food deprivation could cause the lithium effects in the forced-swim test. Treatment with LiCl doses leading to blood levels of 1.3 and 1.4 mmol/l led to highly significant reduction in immobility time in the forced-swim test, but the dose leading to a blood level of 0.8 mmol/l was not different from controls in immobility time. Mice yoked to lithium-induced food deprivation showed no difference in the forced-swim test compared with controls. In conclusion these results suggest that lithium effects in mice in the forced-swim test are dose dependent but not owing to lithium-induced weight loss.

Animals↗
PubMed2005

Wave energy and swimming performance shape coral reef fish assemblages.

Physical factors often have an overriding influence on the distribution patterns of organisms, and can ultimately shape the long-term structure of communities. Although distribution patterns in sessile marine organisms have frequently been attributed to functional characteristics interacting with wave-induced water motion, similar evidence for mobile organisms is lacking. Links between fin morphology and swimming performance were examined in three diverse coral reef fish families from two major evolutionary lineages. Among-habitat variation in morphology and performance was directly compared with quantitative values of wave-induced water motion from seven coral reef habitats of different depth and wave exposure on the Great Barrier Reef. Fin morphology was strongly correlated with both field and experimental swimming speeds in all three families. The range of observed swimming speeds coincided closely with the magnitude of water velocities commonly found on coral reefs. Distribution patterns in all three families displayed highly congruent relationships between fin morphology and wave-induced water motion. Our findings indicate a general functional relationship between fin morphology and swimming performance in labriform-swimming fishes, and provide quantitative evidence that wave energy may directly influence the assemblage structure of coral reef fishes through interactions with morphology and swimming performance.

Animal Structures↗
PubMed2006

Activity of fin muscles and fin motoneurons during swimming motor pattern in the lamprey.

Coordination of motoneuron activity is a fundamental prerequisite for the generation of functional locomotor patterns. We investigate the neural mechanisms that coordinate activity of motoneuron pools in the vertebrate spinal cord with differing phases of activity in the locomotor cycle in a simple motor system, the lamprey swimming network. In the region of dorsal fins the lamprey spinal cord contains two groups of motoneurons: the myotomal motoneurons that innervate the trunk muscles; and the fin motoneurons controlling muscle fibres of the dorsal fins. We investigated the activity of fin muscles during swimming in vivo and that of fin motoneurons during fictive swimming in vitro. During swimming in vivo with cycle periods of 4-8 Hz, fin muscle activity covered a broad portion of the cycle, with the peak of activity out-of-phase to the ipsilateral myotomal muscles. During fictive swimming evoked by N-methyl-d-aspartate in the isolated spinal cord, fin motoneurons expressed similar out-of-phase activity. The phase relationship of the synaptic drive to fin motoneurons was examined by recording their activity intracellular during fictive swimming. Three different forms of membrane potential oscillation with different time courses in the locomotor cycle could be distinguished. Sagittal lesions of the spinal cord in the segment where fin motoneurons are recorded and up to one segment rostral and caudal from it did not influence the out-of-phase activity pattern of the motoneurons. Our results indicate that coordination of fin motoneuron activity with the locomotor activity of myotomal motoneurons does not depend on intrasegmental contralateral premotor elements.

Animals↗
PubMed1995

Enhancement of immobility in a forced swimming test by subacute or repeated treatment with phencyclidine: a new model of schizophrenia.

1. Immobility induced by forced swimming is well known as an animal model of depression. To develop an animal model for the negative symptoms of schizophrenia, in particular the depressive symptoms, the effect of phencyclidine (PCP) on immobility in the forced swimming test was investigated in mice, since PCP produces such negative symptoms in humans. 2. Repeated treatment with PCP (10 mg kg-1 day-1, s.c., once a day for 14 days) prolonged the immobility time in the forced swimming test 24 h after the final injection compared with saline treatment; the effect was not obtained by single or 5 treatments with PCP (10 mg kg-1, s.c.), or by repeated treatment with methamphetamine (0.5 and 1 mg kg-1 day-1, s.c., once a day for 14 days). 3. The enhancing effect of PCP (10 mg kg-1 day-1, s.c.) on the immobility persisted for at least 21 days after the withdrawal of the drug. 4. Haloperidol (0.3 and 1 mg kg-1, p.o.), ritanserin (3 and 10 mg kg-1, p.o.), risperidone (0.1-1 mg kg-1, p.o.), and clozapine (3 and 10 mg kg-1, p.o.) failed to attenuate the immobility induced by the forced swimming in mice repeatedly treated with saline when the drugs were administered 1 h before the forced swimming test. However, ritanserin (30 mg kg-1) and clozapine (30 mg kg-1) did attenuate this immobility. 5. The enhancing effect of PCP on the immobility was attenuated by ritanserin (3 and 10 mg kg-1, p.o.), risperidone (0.3 mg kg-1, p.o.), and clozapine (3 and 10 mg kg-1, p.o.), whereas haloperidol (0.3 and 1 mg kg-1, p.o.) had no effect. 6. These results suggest that the enhancement of immobility in the forced swimming test brought about by repeated PCP treatment could be used as a model of the negative symptoms, particularly the depression, of schizophrenia. This effect of PCP appeared to be mediated, at least in part, via 5-HT2A receptors.

Animals↗
PubMed2005

Effect of thioperamide on modified forced swimming test-induced oxidative stress in mice.

This study was designed i) to investigate the role of histamine H3-receptor ligands on mouse modified forced swimming test, a method that distinguishes the catecholaminergic behaviour with that of serotonergic compounds and ii) to evaluate the role of free radicals in mediation of such effects. Swiss strain albino mice were treated with different doses of histamine H3-receptor antagonist thioperamide (3.75, 7.5 and 15 mg/kg intraperitoneally) and agonist (R)-alpha-methylhistamine (5 microg intracerebroventricularly). The climbing, swimming and immobility times were recorded for 6 min. Immediately after modified forced swimming test, the animals were sacrificed and parameters of oxidative stress were assessed in the brain by measuring the thiobarbituric acid reactive substance (TBARS), glutathione (GSH) and catalase levels. Thioperamide (7.5 and 15 mg/kg intraperitoneally) dose-dependently decreased immobility time and increased swimming time but not climbing time. The behaviour of mice treated with (R)-alpha-methylhistamine was similar to that of control mice. A significant reduction in GSH and an increase in catalase levels were observed in brains of mice exposed to modified forced swimming test. Thioperamide pretreatment dose-dependently reversed such an alteration in oxidative stress parameters. (R)-alpha-methylhistamine caused a reversal of altered catalase but not GSH levels. Thioperamide shows antidepressant effects in the modified forced swimming test and causes a reversal of the test-induced oxidative stress indicating its antioxidant potential. The antidepressant effect of thioperamide appears to be mediated via serotonergic and/or antioxidant mechanisms.

Animals↗
PubMed2006

Effect of swimming on myostatin expression in white and red gastrocnemius muscle and in cardiac muscle of rats.

The aim of this study was to test the hypothesis that swimming training might impact differentially myostatin expression in skeletal muscles, depending on fibre type composition, and in cardiac muscle of rats. Myostatin expression was analysed by real time reverse transcriptase-polymerase chain reaction, Western blot and immunohistochemistry of the red deep portion (mainly composed of slow and type II A fibres) and in the superficial, white portion (composed of fast type II X and II B fibres) of the gastrocnemius muscle in adult male Wistar rats: (i) subjected to two consecutive swimming bouts for 3 h; (ii) subjected to intensive swimming training for 4 weeks; and (iii) sedentary control rats. Myostatin mRNA content was in all cases higher in white than in red muscles. Two bouts of swimming did not alter myostatin expression, whereas swimming training for 4 weeks resulted in a significant reduction of myostatin mRNA contents, significant both in white and red muscles but more pronounced in white muscles. Western blot did not detect any change in the amount of myostatin protein. Immunohistochemistry showed that, in control rats, myostatin was localized in presumptive satellite cells of a few muscle fibres. After training, the number of myostatin-positive spots decreased significantly. Myostatin mRNA content in cardiac muscle was lower than in skeletal muscle and was significantly increased by swimming training. In conclusion, the results obtained showed that intense training caused a decreased expression of myostatin mRNA in white and red skeletal muscles but an increase in cardiac muscle.

Animals↗
PubMed1985

Dual-component amino-acid-mediated synaptic potentials: excitatory drive for swimming in Xenopus embryos.

The neuronal basis of the excitation received by motoneurones during swimming in curarized Xenopus embryos has been investigated further. Extracellular stimulation of axons in the fibre tracts of the spinal cord has been used to evoke unitary excitatory post-synaptic potentials (p.s.p.s) in motoneurones. The p.s.p.s. had a rise time of 3-5 ms and a long falling phase lasting up to 200 ms. These potentials consist of two components: a 'fast' p.s.p. which is insensitive to 50 microM-(+/-)-2-amino-5-phosphonovaleric acid (APV) but is blocked by 2 mM-cis-2,3-piperidine dicarboxylic acid (PDA) and is therefore probably mediated by kainate/quisqualate receptors, and a 'slow' p.s.p. which is blocked by both APV and PDA and is therefore probably mediated by N-methyl-D-aspartate (NMDA) receptors. Paired intracellular recordings from motoneurones and interneurones have revealed a class of spinal cord interneurone which makes descending excitatory amino-acid-dependent synapses onto motoneurones and commissural interneurones. The p.s.p.s evoked by intracellular stimulation of these excitatory interneurones consist of 'fast' and 'slow' components identical in shape and pharmacological properties to those of the extracellularly evoked potentials. One neurone may, therefore, be able to release a transmitter which activates both NMDA and non-NMDA receptors on the same post-synaptic neurone generating fast and slow post-synaptic potentials. The excitatory interneurones play an important role in the generation of the swimming pattern in the curarized Xenopus embryo. Like motoneurones, they fire once per swimming cycle in phase with the ipsilateral motoneurones and receive a background excitation during swimming that is excitatory amino acid mediated. They are therefore part of the swimming rhythm generator. The temporal summation of the extracellularly evoked p.s.p.s shows that these excitatory interneurones are sufficient to generate the excitatory drive received by motoneurones during swimming.

2-Amino-5-phosphonovalerate↗