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PubMed2006

Determination and validity of critical swimming velocity in elite physically disabled swimmers.

The purpose of this investigation was to determine if the critical swimming velocity (CSV), defined as the theoretical maximal swimming velocity that could be maintained for a long period of time without exhaustion, corresponds to the exercise intensity at onset blood lactate accumulation (OBLA), and if it could be utilized as a practical index for assessing endurance performance in elite physically disabled swimmers. Eight elite physically disabled swimmers swam four different distances (50, 100, 200 and 400 m) at maximal effort. The swimming time was taken during each trial. The CSV was expressed as the slope of a regression line between the covered swimming distance and the corresponding times of all possible combinations of 2 or 4 time trials. Results indicate that all the CSVs calculated were similar independently of the distances utilized for their calculation. Afterwards, a CSV confirmation test consisting of 3 x 10-min trials at 95, 100, 105% of the CSV was carried out. The lactate concentration at the end of each trial was 3.32, 4.03 and 5.73 mmol x l(-1), respectively. Lactate concentration at 100% CSV approached the value of 4 mmol x l(-1), which is considered the exercise intensity at OBLA. We conclude that the CSV corresponds with the OBLA intensity and could be a valuable index to plan a training schedule for physically disabled swimmers.

Adult↗
PubMed2003

Strain and gender specific effects in the forced swim test: effects of previous stress exposure.

The chronic mild stress (CMS) procedure was developed in rodents to target anhedonia, the core symptom of depressive melancholia. Stress exposure has been shown to induce a variety of physiological, biochemical and behavioral alterations associated with depression, although its anhedonic consequences as indexed by either sucrose intake and preference or thresholds for brain stimulation reward are less reliably observed. In the present study, we assessed the effects of six weeks of CMS on the latter measure in two strains of male and female rats subsequently challenged with an acute psychophysical stressor, forced swimming; their behavior in the swimming cylinder was evaluated on two consecutive days. While brain stimulation reward thresholds and response rates were unchanged by CMS exposure, significant differences in forced swim behaviors were observed between male control and CMS groups. In particular, male Long Evans rats with a history of CMS showed the largest decrease in the duration of active behaviors on the second test day, a pattern less evident in the Sprague-Dawley strain of rats, or in any of the female groups. The results suggest that the effects of depressogenic manipulations are strain and gender dependent, with male Long Evans rats most susceptible, as demonstrated by the selective reduction of struggling behaviors. Inclusion of multiple measures, including the forced swim test, would provide a better understanding of the psychopathological profile engendered by chronic exposure to mild stressors and its genetic specificity.

Animals↗
PubMed2005

Effects of diving and swimming behavior on body temperatures of pacific leatherback turtles in tropical seas.

Mathematical models and recordings of cloacal temperature suggest that leatherback turtles (Dermochelys coriacea) maintain core body temperature higher than ambient water temperature (T(W)) while freely swimming at sea. We investigated the thermoregulatory capabilities of free-ranging leatherbacks and, specifically, the effect that changes in diving patterns and ambient temperatures have on leatherback body temperatures (T(B)). Data loggers were used to record subcarapace and gastrointestinal tract temperatures (T(SC) and T(GT), respectively), T(W), swim speed, dive depth, and dive times of female leatherback turtles during internesting intervals off the coast of Guanacaste, Costa Rica. Mean T(SC) (28.7 degrees -29.0 degrees C) was significantly higher than mean T(W) (25.0 degrees -27.5 degrees C). There was a significant positive relationship between T(SC) and T(W) and a significant negative correlation between T(SC) and dive depth and T(GT) and dive depth. Rapid fluctuations in T(GT) occurred during the first several days of the internesting interval, which suggests that turtles were ingesting prey or water during this time. Turtles spent 79%-91% of the time at sea swimming at speeds greater than 0.2 m s(-1), and the average swim speed was 0.7 +/- 0.2 m s(-1). Results from this study show that alterations in diving behavior and T(W) affect T(B) of leatherback turtles in the tropics. Body temperatures of free-ranging leatherback turtles correspond well with values for T(B) predicted by mathematical models for tropical conditions.

Animals↗
PubMed2005

Postexercise physiology and repeat performance behaviour of free-swimming smallmouth bass in an experimental raceway.

We studied postexercise physiology and behaviour of smallmouth bass (Micropterus dolomieu) that voluntarily ascended experimental raceways of varying length (20-50 m) against water velocities ranging from 8 to 120 cm/s. Our first objective was to link mean swimming speed to metabolism using patterns in postexercise muscle glycogen, muscle lactate, and plasma lactate. Our second objective was to examine several behavioural indices (attempt rate, success rate, and recovery time between an ascent and a subsequent attempt) and determine whether patterns in these data reflected those from the physiological measurements. Postexercise muscle glycogen and plasma lactate data suggest that smallmouth bass powered swimming speeds up to 70-80 cm/s using energy from aerobic processes. However, lactate did not begin to accumulate in the white muscle until speeds in excess of 120-130 cm/s were reached. The behavioural parameters measured did not indicate the presence of a physiological threshold at 70-80 cm/s; however, patterns in all factors changed appreciably when fish maintained speeds in excess of 120-130 cm/s. Therefore, it is clear that behaviour and physiology are tightly linked in this species and that maximum aerobic swimming capacity may not limit performance (or re-performance) during short-duration swims.

Animals↗
PubMed2005

Changes in the condition factor have an impact on metabolic rate and swimming performance relationships in Atlantic cod (Gadus morhua L.).

In the field, Atlantic cod face seasonal changes in food availability that in turn lead to changes in condition. To examine the physiological consequences of these changes in condition, we measured routine metabolic rate (RMR) to estimate standard metabolic rate (SMR), active metabolic rate (AMR), aerobic scope, critical swimming speed (Ucrit), cost of transport, sprint performance, time to exhaustion, and postexhaustion metabolic rate (EMR) for 24 Atlantic cod from the Gulf of St. Lawrence. Cod were measured at their initial condition (condition factor of 0.676+/-0.076) and after 9 wk of feeding (condition factor of 0.923+/-0.096). These levels of condition are representative of wild cod in the Gulf of St. Lawrence during the spring and during the fall-early winter, respectively. The improved condition did not change mass-specific SMR. However, mass-specific AMR, aerobic scope, and EMR decreased with the improvement in condition. The various measures of swimming performance were affected differently. Ucrit increased and cost of transport at 1.3 and 1.5 body lengths s(-1) decreased with improved condition, but the cost of transport at 0.3, 0.9, 1.1, 1.7, and 1.9 body lengths s(-1), sprint performance, and time to exhaustion did not change. Hierarchies for the speed at first burst-coast, the proportion of Ucrit supported by burst-coasts, and time to exhaustion were maintained with the improvement in condition. The relationships between metabolic rates and swimming performance differed with condition level, with stronger correlations apparent in the cod at their initial condition. Given the low condition of wild cod stocks, these responses indicate that reduced performance, due to both maintenance of metabolic expenditures and modified swimming capacities, may impair survival under conditions of reduced food availability.

Animals↗
PubMedDate not supplied

Heart rate, swimming speed, and estimated oxygen consumption of a free-ranging southern elephant seal.

Heart rate, swimming speed, and diving behaviour were recorded simultaneously for an adult female southern elephant seal during her postbreeding period at sea with a Wildlife Computers heart-rate time depth recorder and a velocity time depth recorder. The errors associated with data storage versus real-time data collection of these data were analysed and indicated that for events of short duration (i.e., less than 10 min or 20 sampling intervals) serious biases occur. A simple model for estimating oxygen consumption based on the estimated oxygen stores of the seal and the assumption that most, if not all, dives were aerobic produced a mean diving metabolic rate of 3.64 mL O2 kg-1, which is only 47% of the field metabolic rate estimated from allometric models. Mechanisms for reducing oxygen consumption while diving include cardiac adjustments, indicated by reductions in heart rate on all dives, and the maintenance of swimming speed at near the minimum cost of transport for most of the submerged time. Heart rate during diving was below the resting heart rate while ashore in all dives, and there was a negative relationship between the duration of a dive and the mean heart rate during that dive for dives longer than 13 min. Mean heart rates declined from 40 beats min-1 for dives of 13 min to 14 beats min-1 for dives of 37 min. Mean swimming speed per dive was 2.1 m s-1, but this also varied with dive duration. There were slight but significant increases in mean swimming speeds with increasing dive depth and duration. Both ascent and descent speeds were also higher on longer dives.

Animals↗
PubMedDate not supplied

Is there a need for state health department sanitary codes for public hydrotherapy and swimming pools?

The Board of Health of the Commonwealth of Virginia has an outdated sanitary code for its public hydrotherapy and swimming pools. The code is restricted to pools in hotels and other lodging places. The absence of modern regulations for public hydrotherapy and swimming pools has permitted serious deficiencies in pool maintenance, which are highlighted in this report. The most notable of these deficiencies was the presence of high levels of bacterial contamination that could predispose to infect in the water of one public hot tub. The results of this study indicate that the Virginia Board of Health sanitary code for pool water must be revised immediately and should include all public hydrotherapy and swimming pools. Other states and communities may want to assess their codes for swimming pools and hydrotherapy tubs to avoid deficiencies that could be detrimental to public health.

Bacteria↗
PubMed1999

A meta-analysis of swimming and water precautions.

OBJECTIVE: To reconcile conflicting reports concerning the incidence of otorrhea in children with tympanostomy tubes who swim without ear protection. STUDY SELECTION: Articles were identified by MEDLINE search, Current Contents, and references from review articles, textbook chapters, and retrieved reports. Controlled trials of water precautions following tympanostomy tube placement were selected by independent observers and scored on 10 measures of study validity. Five English-language articles met all inclusion criteria. DATA EXTRACTION: Data were abstracted for an endpoint of otorrhea following swimming without ear protection with a minimum follow-up of 6 weeks. DATA SYNTHESIS: Pooled analysis of 619 children revealed a rate difference of -5.04 (95% confidence interval [CI], -11.62 to 1.54). No significant difference in the incidence of otorrhea was noted between patients who swam without ear protection and nonswimmers. CONCLUSION: There is no increase in incidence of otorrhea in children who swim without ear protection compared with children who do not swim following tympanostomy tube placement.

Cerebrospinal Fluid Otorrhea↗
PubMed1998

Performance and drag during drafting swimming in highly trained triathletes.

PURPOSE: The influence of drafting was studied on the swimming performance, metabolic response, and passive drag of eight triathletes. METHODS: The performance in drafting position was measured directly behind another swimmer during a 400-m swim and compared with the nondrafting position. Metabolic response concerned VO(2), blood lactate, stroke rate, stroke length, and rating of perceived exertion. Drag was measured by passive towing. RESULTS: In drafting position, the triathletes swam on average faster (3.2%) over the 400-m swim than in nondrafting position (4 min, 47.69 +/- 10.35 s vs 4 min, 57.25 +/- 7.24 s; P < 0.01). Blood lactate and stroke rate were significantly lower (9.6 mM vs 10.8 mM; 39.9 cyclexmin(-1) vs 41.3 cyclexmin(-1) P < 0.02) and stroke length higher (2.10 mx cycle(-1) vs 1.97 mxcycle(-1), P < 0.01) than in nondrafting position. VO(2) and rating of perceived exertion were not statistically different. Passive drag was lower in drafting than in nondrafting position (P < 0.01). However, the gain in drag decreased with the towed velocity (from 26% at 1.1 mxs(-1) to 13% at 1.7mxs(-1)). In drafting position, the performance gain was related to the 400-m time (r = 0.80, P < 0.01) and to the skinfold thickness (r = 0.94, P < 0.01), with faster and leaner swimmers having greater gains of performance. CONCLUSIONS: Swimming behind another swimmer in a race is advantageous for triathletes.

Adult↗
PubMed2000

Arm and leg power output in swimmers during simulated swimming.

PURPOSE: Previously, it has not been possible to compare power output of the arms and legs during simulated swimming using dry-land ergometry. The purpose of this study was to determine arm-pulling and leg-kicking power using isokinetic dry-land ergometry. METHODS: Twenty-two highly trained male swimmers of mean (+/- SD) age, 23 +/- 3.6 yr; body mass, 78 +/- 5.9 kg; and stature, 1.79 +/- 0.04 m were recruited to the study. First, subjects performed 10 s of all-out exercise at each of five resistance settings, with 1 h rest in between, to determine the best maximal pull velocity (MPVopt). Second, they performed an all-out 30-s test at MPVopt, which was repeated the following day. These repeated 30-s tests were performed separately using simulated front-crawl arm-pulling and leg-kicking, on a computer-interfaced swim bench and purpose-built leg-kicking ergometer. Peak and mean power output (PPO; MPO) were determined from regression analysis of the power vs time relationship. RESULTS: The mean (+/- SEM) PPO for arms and legs were 304 +/- 22 W versus 435 +/- 36 W. For MPO, the means were 225 +/- 31 W vs 312 +/- 26 W, respectively. These values were attained at mean MPVopt of 2.5 +/- 0.2 m x s(-l) for arms and 2.3 +/- 0.4 m x s(-1) for legs. The variation in PPO from repeated testing was 7.3% for arms and 8.3% for legs. CONCLUSIONS: These results show that the legs can sustain greater power output than the arms during simulated swimming. Also, the intra-subject variation in measurement of power output is small using these dry-land ergometers. These methods of assessment might be useful in explaining swimming performance and in monitoring changes that take place during training.

Adolescent↗
PubMed1986

Feasibility of extended wear lens use in chlorinated swimming pools.

A group of 14 active swimmers was studied to evaluate corneal and conjunctival health immediately after extended wear contact lenses were worn in a chlorinated swimming pool. Two different lenses, a high (70%) and a low (38%) water content, were used for each subject in order to compare the corneal response to the high and low water content lenses. No significant difference in corneal and conjunctival response was found between the two lenses. Statistically significant differences were seen in corneal thickness and halo size between swimming with and without contact lenses. Corneal superficial erosion was of greater concern under both the control and test conditions, but this is believed to be due to unforeseen experimental design errors. The frequency of contact lens loss in this study was 3.57%. Hence, the conclusion that the rate of loss of hydrophilic lenses in a swimming situation is not the only concern in regard to lens wear during swimming, but there are other important factors such as lens adherence to the cornea and bacterial contamination of the lenses that need to be studied further.

Chlorine↗
PubMed1988

Extended wear contact lens movement under swimming pool conditions.

On site swimming pool studies have indicated that soft contact lenses adhere to the cornea when exposed to swimming pool water. It was the aim of this investigation to study, under controlled laboratory conditions, both the adherence of hydrophilic extended wear lenses and any changes in lens movement with exposure to swimming pool water. Normal saline and a hypotonic solution having a pH and osmolality identical to the pool water served as controls. Exposure to both swimming pool water and the hypotonic solution promptly caused both lenses to stop moving and adhere to the cornea. Notably, the instillation of normal saline also caused a dramatic decrease in lens movement for some subjects.

Adolescent↗
PubMed1997

Aminergic modulation of glycine release in a spinal network controlling swimming in Xenopus laevis.

1. Neuromodulators can effect changes in neural network function by strengthening or weakening synapses between neurons via presynaptic control of transmitter release. We have examined the effects of two biogenic amines on inhibitory connections of a spinal rhythm generator in Xenopus tad poles. 2. Glycinergic inhibitory potentials occurring mid-cycle in motoneurons during swimming activity are reduced by 5-hydroxytryptamine (5-HT; serotonin) and enhanced by noradrenaline (NA). These opposing effects on inhibitory synaptic strength are mediated presynaptically where 5-HT decreases and NA increases the probability of glycine release from inhibitory terminals. 3. The amines also have contrasting effects on swimming: 5-HT increased motor burst durations while NA reduced swimming frequency. Aminergic modulation of glycinergic transmission may thus control fundamental parameters of swimming and force the spinal network to generate opposite extremes of its spectrum of possible outputs.

Animals↗
PubMed1998

Effects of a movement and swimming program on vital capacity and water orientation skills of children with cerebral palsy.

Swimming and aquatic exercise are known for their effects on respiration in normal and asthmatic people. The purpose of the present study was to evaluate the effect of a 6-month movement and swimming program on the respiratory function and water orientation skills of children with cerebral palsy (CP). Forty-six kindergarten children aged 5 to 7 years were assigned either to a treatment or control group. The intervention program consisted of swimming sessions twice weekly and sessions of group physical activity in a gym once weekly, each session lasting 30 minutes, for a period of 6 months. Children in the control group were treated (30 minutes, 4 days per week) with Bobath physical therapy. The children in the treatment and control groups had comparable disability types, age, and anthropometric measurements. A 2 x 2 (group x test period) repeated measures ANOVA design confirmed a significant effect of interaction of time with group. The results also confirmed that children with CP have reduced lung function compared with normative data for children in the same age category. The treatment program improved baseline vital capacity results by 65%, while children in the control group improved by only 23%. The movement and swimming exercise program had a better effect than a physical therapy routine implemented in a previous study, consisting of respiratory exercise alone.

Analysis of Variance↗
PubMed1993

Sex differences in acute swim stress-induced changes in the binding of MK-801 to the NMDA subclass of glutamate receptors in mouse forebrain.

Acute swim stress (3 min at 32 degrees C) in mice produces increases in the binding of MK-801 to the NMDA subclass of glutamate receptors to forebrain membranes prepared from male mice. Scatchard analyses indicate that the observed increases in the binding of MK-801 in membranes from male mice are the result of changes in the affinity and density of low-affinity binding sites and in the density of high-affinity binding sites. In female mice, any changes in the binding of MK-801 appear to be much less pronounced and restricted to the low-affinity binding sites. These results are in contrast to the situation with binding to GABA receptors where acute swim stress increases GABA binding in forebrain membranes much more in female than in male mice. This indicates significant sex differences in the responses of receptors for the major excitatory and inhibitory transmitters to acute swim stress. These rapid changes in MK-801 binding may result from changes in endogenous modulators as appears to be the case in the acute swim stress-induced changes in GABA binding. As with GABA binding, the endogenous modulators are likely to include steroids, the sex differences reflecting differences in modulation by gonadal steroids and the stress-induced changes reflecting differences in modulation by adrenal steroids. Estradiol, progesterone, and corticosterone treatments have been reported by other workers to influence the properties of glutamate receptors.

Analysis of Variance↗
PubMed2002

Detection of Microsporidia, cryptosporidia and Giardia in swimming pools: a one-year prospective study.

In order to estimate the rate of microsporidia, cryptosporidia and giardia contamination of swimming pools, sequential samples of water were collected during a one-year period in six different swimming pools in Paris, France. Fourty-eight samples were submitted to filtrations. Eluates were examined for microsporidia using polymerase chain reaction (PCR) and for cryptosporidia and giardia using immunofluorescence staining. One of 48 specimens was positive for microsporidia. Using DNA sequence analysis, unknown microsporidia species were identified, which were close to an insect microsporidia Endoreticulatus schubergi. One sample was positive for cryptosporidia and none were positive for giardia. This study shows a low level of swimming pool water contamination by microsporidia, cryptosporidia or giardia, demonstrating the efficacy of cleaning filtration and disinfection procedures used in French swimming pools.

Animals↗
PubMed1992

Respective effects of malnutrition and phosphate depletion on endurance swimming and muscle metabolism in rats.

To examine the respective roles of malnutrition and phosphate depletion on muscle exercise capacity and bioenergetics, phosphate-depleted, either underfed or partly refed rats; phosphate-supplemented, either underfed or partly refed rats; and well-nourished control animals were studied, using swim time to exhaustion and 31P NMR spectroscopy measurements of muscle phosphocreatine, inorganic phosphate, adenosine triphosphate and intracellular pH. Only partly refed rats displayed hypophosphataemia. Swim time to exhaustion was lower in non-refed rats than in controls. Among the four groups, both refeeding and phosphate depletion positively affected swim time to exhaustion (both with P less than 0.02), and swim time to exhaustion was negatively correlated with phosphataemia (P less than 0.05). At rest, the ratio of muscle phosphocreatine/inorganic phosphate was lower in the phosphate-supplemented rats than in controls, whereas muscle phosphocreatine/adenosine triphosphate and intracellular pH were comparable. After non-tetanic stimulation, the muscle phosphocreatine recovery was slower in the four groups than in controls and closely correlated with exhaustion (P less than 0.01). These findings suggest that malnutrition alters the capacity of muscular work, mainly because of a reduced cell oxidative energy availability. These patterns are improved by partial refeeding and clearly influenced by the level of phosphorus intake, whether depletion is capable of improving metabolic alterations or uncontrolled supplementation is deleterious in malnourished animals.

Animals↗
PubMed1970

Hormonal effects on ontogeny of swimming ability in the rat: assessment of central nervous system development.

The maturation of swimming behavior and the evoked cortical response to sciatic stimulation were studied in newborn rats receiving thyroxine or cortisol. Compared to that of controls the maturation of swimming is accelerated or delayed 2 to 3 days by thyroxine or cortisol treatment, respectively, and this corresponds to ontogenetic shifts in the characteristics of the evoked potential. Front leg movement during swimming normally diminishes at about 16 days of age and is inhibited by day 22. Thyroxine also advances and cortisol delays the age at which this inhibitory mechanism becomes evident, and compresses (thyroxine) or expands (cortisol) the time interval over which it becomes functional. During early postnatal life certain circuilating hormones can affect the rate and chronology of central nervous system maturation. Swimming behavior may be a simple model to use in studies concerned with factors affecting the functional and behavioral development of the central nervouts system.

Aging↗