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PubMed1990

The contribution of passive drag as a determinant of swimming performance.

The purpose of the present investigation was to evaluate the contribution of passive drag (Dp) to the prediction of a 400-m swim. A second aim was to evaluate the relation between Dp and some anthropometric factors. In a first experiment, 84 swimmers (both sexes) had their Dp (at 1.4 m.s-1) and VO2max measured in water and put into relation with the performance time of a 400-m swim. Performance times were mainly related to VO2max (r = 0.70 and 0.72, p less than 0.01, for male and female swimmers, respectively). Inclusion of Dp as a second variable improved significantly (p less than 0.01) the accuracy of the regression up to 0.75 and 0.78. Passive drag was also significantly (p less than 0.01) related to height (r = 0.80 and 0.60, p less than 0.01, for male and female swimmers, respectively), weight (r = 0.78 and 0.54, p less than 0.01, for males and females, respectively), and body surface area (r = 0.80 and 0.58, p less than 0.01, for males and females, respectively). In a second group of 7 male swimmers, it was found that Dp values were increased on average by 34% (p less than 0.01) when measured after a maximal expiration as compared to measurements after a maximal inspiration. In a third group of swimmers (n = 41) for which generalized joint laxity was measured, it was found that this variable contributes significantly to the Dp variability. The present results show that Dp can be considered as contributing significantly to prediction of performance in swimming.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1989

A comparative study of blood lactate tests in swimming.

Three different modes of lactate tests were studied. Eleven male competitive swimmers performed the tests (n.100 m, n.300 m, 2.100m + 2.400 m) within 5 days. Swimming velocity (V) vs blood lactate (BLa) and V vs heart rate (HR) curves were averaged. In V vs BLa comparisons, the BLa values of 4 mmol.l-1 in 2.400 m, 3 mmol.l-1 in n.300 m, and 2 mmol.l-1 in n.100 m modes were found to correspond to the same V. Although the resting BLa values were similar before the testing occasions, the initial BLa value in very easy swimming was lower in the n.300 m than in the n.100 m mode. The elimination of lactate most probably caused this difference. The highest BLa value was measured in the n.100 m (14.9 mmol.l-1) and 2.100 m (13.6 mmol.l-1) exercise modes demonstrating a higher rate of anaerobic energy production than in the n.300 m or 2.400 m test modes. In HR vs V comparison, the n.300 m and 2.400 m modes demonstrated similar HR values in relation to V. To measure the whole intensity area, a combination of tests should be applied by performing an incremental set with several steady-state loadings (aerobic) and one or two 100 m swims (anaerobic) in one test session.

Adolescent↗
PubMed1995

Relationships between perceived exertion and physiological variables during swimming.

The relationships between perceived exertion and the physiological variables oxygen uptake (VO2), heart rate (HR) and blood lactate concentration (HLa) were studied in tethered swimming. Seven male and ten female subjects swam at five submaximal intensities. The degree of perceived exertion was measured both on the category scale (RPE) and on the category-ratio scale (CR-10). All five dependent variables (VO2, HR, HLa, RPE and CR-10) were described by the equation R = a+c (S-b)n with the drag (D) in tethered swimming as an independent variable. The relationships between D and VO2, HR and RPE were linear with a level of fitness correlation (r = 0.989-0.999) for both males and females. The HLa exponents were 3.2 for males (r = 1.000) and 3.6 for females (r = 0.991), and CR-10 were 1.5 for males (r = 0.998) and 1.9 for females (r = 1.000), respectively. The growth functions for males and females were very similar. The conclusion is that RPE is effective as a measure of exercise intensity and can be used for exercise prescription in practical swimming.

Adult↗
PubMed1987

Red cell oxygen transport before and after short-term maximal swimming in dependence on training status.

Parameters of oxygen transport were determined in 12 national class swimmers of both sexes during a 6-week training phase. Training intensity was high at the beginning of the training period (60 km/week); at the end the intensity was reduced to 25 km/week. At the beginning, in the middle, and at the end of the training period maximal swim tests (3 X 50 m) were performed. At rest 2,3-diphosphoglycerate (2,3-DPG) concentration (+0.82 mmol/l RBC) and P50 values (+0.92 mmHg) were increased after the period of intensive training, but decreased during the following 3 weeks, remaining still higher than pre-training values. Hemoglobin (Hb), concentration (MCHC) decreased during the training phase in dependence on training intensity. On day 0 and day 25 no changes in 2,3-DPG were found during the swim tests, but at the end a significant reduction in red cell 2,3-DPG (-0.44 mmol/l RBC) occurred. This can be explained by the more pronounced lactacidosis in this last swim test. The degree of hemoconcentration during exercise was the same throughout the training period and consequently independent of the state of physical fitness. During the training period, a good correlation between training intensity, increase in red cell 2,3-DPG, and P50 value as well as in the degree of sports anemia could be found.

2,3-Diphosphoglycerate↗
PubMed1987

Metabolic and hormonal responses to long-distance swimming in cold water.

The acute effects of long-distance swimming in cold water on selected hormonal and metabolic variables were evaluated on 22 long-distance swimmers (16 males and 6 females) during a 32-km swimming competition (La Traversée Internationale du Lac St-Jean). The water temperature was 18.5 degrees C and the mean performance times were 8 h and 32 min for men (M) and 9 h and 1 min for women (F). The blood samples were withdrawn in the fasting state during the week preceding the event and within 30 min after completion of the race. A positive correlation was obtained, for both groups, between percent body fat and rectal temperature measured at the end of the competition. After the competition, an increase in plasma epinephrine, norepinephrine, cortisol, thyroxine, free fatty acids, lactate, a decrease in glucose and insulin and no change in growth hormone, triiodothyronine, triglycerides, and cholesterol concentrations were observed in both groups. The increase in plasma thyroxine was more pronounced in the slower swimmers while the change in blood cortisol concentrations was higher in the subjects having the most acute decrease in body temperature. Male and female swimmers have a similar metabolic and hormonal response to a long-distance swimming competition in cold water.

Adolescent↗
PubMed1985

Glomerular filtration rate in intact and splenectomized running and swimming dogs.

The glomerular filtration rate (GFR) was measured using a continuous inulin infusion in control, treadmill running, and swimming experiments in intact and splenectomized dogs. There was a 20% increase in the GFR after swimming in the splenectomized dogs as compared to the corresponding value in the control trials (P less than 0.01). The GFR was not changed during or after running or during swimming. Possible mechanisms maintaining the GFR in intact and splenectomized dogs during exercise are discussed.

Animals↗
PubMed1994

A swimming-associated outbreak of hemorrhagic colitis caused by Escherichia coli O157:H7 and Shigella sonnei.

BACKGROUND: In the summer of 1991, simultaneous outbreaks of bloody diarrhea and hemolytic-uremic syndrome caused by Escherichia coli O157:H7 and of bloody diarrhea caused by Shigella sonnei were traced to a lakeside park near Portland, Oregon. METHODS: We identified cases primarily from routine surveillance reports. In case-control studies, the activities of persons with park-associated E. coli O157:H7 or S. sonnei infections were compared independently with those of three sets of controls. We also evaluated environmental conditions at the park and subtyped the bacterial isolates. RESULTS: We identified 21 persons with park-associated E. coli O157:H7 infections (all of them children; median age, six years) and 38 persons with S. sonnei infections (most of them children). These 59 people had visited the park over a 24-day period. Their illnesses were not associated with food or beverage consumption. All the case patients reported swimming, however, and in case-control studies swimming was strongly associated with both types of infection (P = 0.015 or less). The case patients were more likely than the controls to report having swallowed lake water, and they had spent more time in the lake. Numbers of enterococci indicative of substantial fecal contamination (geometric mean, > 50 per deciliter) were detected in the swimming area during some but not all of the outbreak period. Park-associated E. coli O157:H7 isolates were identical by pulsed-field gel electrophoresis and were distinguishable from other isolates in the Portland area. CONCLUSIONS: Lake water that was fecally contaminated by bathers was the most likely vehicle for the transmission of both the E. coli O157:H7 and the S. sonnei infections. The unusually prolonged outbreak suggests both the survival of these enteric organisms in lake water and a low infectious dose.

Case-Control Studies↗
PubMed2003

Swimming-induced pulmonary edema.

Pulmonary edema of water immersion, which is not associated with aspiration or a closed glottis, is infrequently described in the literature. Swimming-induced pulmonary edema is a syndrome whose pathophysiologic characteristics have not been fully elucidated. Immersion alone has marked effects on central vascular volume, redistribution of pulmonary blood flow, and lung volumes. These changes are more prominent in cold water. These changes, coupled with an elevated cardiac output, may expose regions of the capillary bed to high pressures that favor the extravasation of fluid by hydrostatic forces and potential stress failure of the capillaries. Patients with swimming-induced pulmonary edema present with dyspnea, cough, hypoxemia, and occasionally hemoptysis. Physical examination and chest radiographs usually reveal evidence of pulmonary edema. Treatment is symptomatic and conservative. Improvement and resolution of symptoms are usually rapid, with radiographic normalization in 24 to 48 hours. We describe here 3 cases of swimming-induced pulmonary edema.

Adult↗
PubMed2004

Pathways of trihalomethane uptake in swimming pools.

Chlorination of pool water leads to the formation of numerous disinfection by-products (DBPs), chloroform usually being most abundant. Bathers and pool guardians take up various amounts of DBPs by different pathways. Identification of different uptake paths is important in order to develop a technical strategy for swimming pool water treatment and to develop focussed technical solutions to minimize THM uptake. Basically, trihalomethanes (THMs) can be taken up by inhalation, by dermal absorption, or orally (swallowing of water). In our experimental study involving up to 17 participants we quantified the body burden resulting from exposure to three different concentrations of chloroform in water and air of an indoor swimming pool, during a 60 min exercising period. Chloroform concentration of the water was 20.7, 7.1, and 24.8 microg/l and was not influenced artificially. Corresponding air CHCl3 concentrations were measured at two different levels (20 cm and 150 cm) and ranged from to 85 to 235 microg/m3. To dissociate the dermal exposure route from that of inhalation, THM concentrations were measured in the blood of subjects practicing in an indoor pool with and without scuba tanks, as well as in the blood of subjects walking around the pool without swimming. Chloroform concentrations were measured in blood samples before and after each exercise period. Blood chloroform concentration of participants with scuba tanks was 0.32 +/- 0.26 microg/l, without scuba tanks 0.99 +/- 0.47 micro/l, and for persons walking around the pool 0.31 +/- 0.25 microg/l. Our results indicate that THMs are mainly taken up over the respiratory pathway. Only about one third of the total burden is taken up over the skin. We examined the relationship between blood concentration and environmental chloroform concentrations by using linear regression models. Blood concentrations are correlated to air chloroform concentrations; correlation to water concentrations is less obvious.

Adult↗
PubMed2003

Inspiratory muscle fatigue in swimmers after a single 200 m swim.

Inspiratory muscle fatigue may occur in as little as 6 min during high-intensity spontaneously breathing exercise. The aims of this study were to determine whether inspiratory muscle fatigue occurs during swimming exercise and whether inspiratory muscle strength differs between the supine and standing body positions. Seven competitive swimmers were recruited to perform a single 200 m front-crawl swim, corresponding to 90-95% of race pace. Inspiratory muscle strength was measured at residual volume using a hand-held mouth pressure meter that measured maximal inspiratory pressure in the upright and supine positions. At baseline, maximal inspiratory pressure in the supine position was significantly lower than maximal inspiratory pressure in the upright position (112 +/- 20.4 and 133 +/- 16.7 cmH2O, respectively; P < or = 0.01). Post-exercise maximal inspiratory pressure in the supine position (80 +/- 15.7 cmH2O) was significantly lower than baseline maximal inspiratory pressure in the supine position (P < or = 0.01). The results indicate that a single 200 m front-crawl swim corresponding to 90-95% of race pace was sufficient to induce inspiratory muscle fatigue in less than 2.7 min. Furthermore, although diaphragm muscle length is optimized when supine, our results indicate that the force output of the diaphragm and inspiratory accessory muscles is greater when upright than when supine.

Adult↗
PubMed1992

Effect of induced alkalosis on swimming time trials.

Previous studies have shown that sodium bicarbonate ingestion prior to exercise may improve performance during repeated (interval) bouts. To examine the practical implications of such findings, seven collegiate swimmers participated in simulated swim competitions of multiple events following sodium bicarbonate (B) ingestion, placebo (P) ingestion and control (C--no ingestion) treatments. Each swimmer reported to the laboratory 1 h prior to the simulated competitions (72 h apart) and was randomly assigned to one of the three experimental treatments. Competition consisted of one relay (100 yards; 91.4 m) and two individual (200 yards; 182.8 m) swimming events with 20 min rest between events. Analysis of variance (ANOVA) with repeated measures revealed no significant differences in performance times as a result of the three treatments (P greater than 0.05). The results suggest that sodium bicarbonate ingestion prior to swim competition consisting of significant rest intervals between events is not an ergogenic procedure.

Adult↗
PubMed1998

The relationship between blood lactate and heart rate responses to swim bench exercise and women's competitive water polo.

The aim of this study was to explore the relationship between physiological responses to dry-land testing and to water polo playing. Eight female water polo players (mean+/-s: age 26.7+/-5.7 years, height 169+/-6 cm, body mass 65.3+/-7.0 kg) participated in two assessments. The first involved a discontinuous incremental arm test to exhaustion on an isokinetic swim bench. Blood lactate was determined from finger-prick blood samples and heart rate was recorded at increasing exercise intensities. The highest (peak) values for blood lactate (5.1+/-0.2 mmol l(-1)), exercise intensity (79+/-5.2 W) and heart rate (146+/-6 beats min(-1)) were recorded at exhaustion. Also, the exercise intensity and heart rate at a blood lactate concentration of 4 mmol l(-1) were established. The second assessment involved determination of blood lactate and heart rate immediately after each quarter of a different water polo game for each subject. The mean (+/-s(x)) blood lactate and heart rate for each quarter of the game were as follows: 3.5+/-0.4, 4.3+/-0.5, 4.3+/-0.7 and 4.6+/-0.5 mmol l(-1); 138+/-10, 149+/-12, 151+/-9 and 154+/-8 beats min(-1), respectively. None of the peak values on the swim bench correlated with blood lactate or heart rate responses to game-playing. However, the mean exercise intensity at 4 mmol l(-1) lactate (64+/-5 W) correlated with the fourth quarter values of both blood lactate concentration (r=-0.82, P=0.01) and heart rate (r=-0.93, P< 0.001). These results show that submaximal metabolic responses to exercise on a swim bench are closely correlated with metabolic responses to water polo game-playing.

Adult↗
PubMed1999

The effect of longer-term creatine supplementation on elite swimming performance after an acute creatine loading.

We investigated the effect of an acute creatine loading (25 g per day for 4 days) and longer-term creatine supplementation (5 g of creatine or 5 g of placebo per day for 2 months) on the performance of 22 elite swimmers during maximal interval sessions. After the acute creatine loading, the mean of the average interval swim times for all swimmers (n = 22) improved (44.3+/-16.5 s before vs. 43.7+/-16.3 s after supplementation; P<0.01). Three of the 22 swimmers did not respond positively to supplementation. After 2 months of longer-term creatine supplementation or placebo, neither group showed a significant change in swimming performance (38.7+/-13.5 s before vs. 38.7+/-14.1 s after for the creatine group; 48.7+/-18.0 s before vs. 48.7+/-18.1 s after for the placebo group). We conclude that, in elite swimmers, 4 days of acute creatine loading improves swimming performance significantly when assessed by maximal interval sessions. However, longer-term supplementation for 2 months (5 g of creatine per day) did not benefit significantly the creatine group compared with the placebo group.

Adult↗
PubMed1999

Determining propulsive force in front crawl swimming: a comparison of two methods.

To evaluate the propulsive forces in front crawl arm swimming, derived from a three-dimensional kinematic analysis, these values were compared with mean drag forces. The propulsive forces during front crawl swimming using the arms only were calculated using three-dimensional kinematic analysis combined with lift and drag coefficients obtained in fluid laboratories. Since, for any constant swimming speed, the mean propulsive force should be equal to the mean drag force acting on the body of the swimmer, mean values of the calculated propulsive forces were compared with the mean drag forces obtained from measurements on a Measuring Active Drag (MAD) system. The two methods yielded comparable results, the mean difference between them being only 5% (2 N). We conclude that propulsive forces obtained from three-dimensional kinematic analysis provide realistic values. The calculation of the propulsive force appears to be rather sensitive to the point on the hand at which the velocity is estimated and less sensitive to the orientation of the hand.

Adult↗
PubMed1993

Path analysis of a self-esteem model across a competitive swim season.

An adaptation of the previously developed Exercise and Self-Esteem Model (Sonstroem & Morgan, 1989) was tested longitudinally with 93 male interscholastic swimmers from nine high schools who were evaluated at pre-, mid-, and postseason. Swimmers completed three self-perception scales that ranged from evaluations of specific swim skills (SKILL) through broader perceived physical competence (PC) to global self-esteem (SE). Performance scores (PERF) were calculated across events by standardizing swim times to a mean of 0 and a standard deviation of 1. Structural modeling analysis across the three time waves indicated an excellent data fit (chi 2 = 25.46, p > .15). The model was able to explain 84, 83, and 80% of PC, SKILL, and PERF, respectively, at the third testing period. Swim improvement tended to be small (median change = 2.9%). Relationships among variables at each testing period and among the same variables at different testing periods were large and as hypothesized. Several significant relationships occurred between different variables across different testing periods. These were not extinguished when social desirability was added to the model. Social desirability failed to significantly influence subsequent measures of any model variable.

Adolescent↗
PubMed2006

Influence of branched-chain amino acid supplementation on urinary protein metabolite concentrations after swimming.

OBJECTIVE: The influence of branched-chain amino acid (BCAA) supplementation on urinary urea nitrogen, hydroxyproline (HP), and 3-methylhistidine (3MH) concentrations after 25 min of breast stroke exercise (65-70% maximum heart rate reserved, 65-70% HRRmax) followed by a 600 m crawl stroke competition was investigated in a double-blind, counter-balanced study. METHODS: Male university students (19-22 years old) majoring in physical education participated in the study. Based on the previous swimming time of a 600 m crawl stroke, the participants were divided into two groups: placebo (n = 9, BMI = 24.2 +/- 2.1 kg/m2; 12 g of glucose/day; in capsules) and BCAA (n = 10, BMI = 22.7 +/- 1.5 kg/m2; 12 g of BCAAs/day; in capsules: leucine 54%, isoleucine 19%, valine 27%) groups. The participants maintained a regular dietary intake (except the prescribed breakfast on day 15) and exercise activity at a moderate/low intensity (60-70% HRRmax, swimming and rowing, approximately 1.5 hour/day) during the 15-day study. A prescribed exercise program was performed on day 15. Urinary and blood samples were collected before, during, and after the prescribed exercise for the measurements of the urinary urea nitrogen, HP, and 3MH concentrations in urine, as well as the glucose, lactate, glutamine, alanine, and BCAA concentrations in plasma. RESULTS: Two weeks of dietary supplementation did not induce any changes in the plasma glucose and total BCAA concentrations of either group, nor in the urinary urea nitrogen, HP, and 3MH concentrations in urine. On day 15, after 25 min of breast stroke exercise and a 600 m crawl stroke competition, plasma glucose concentration decreased significantly (p < 0.05) whereas plasma lactate concentration increased significantly (p < 0.05) in both groups. The exercise program prescribed in the study did not affect urinary urea nitrogen, HP, and 3MH concentrations. Twenty hours after the competition, however, a significant increase in the concentrations of urinary urea nitrogen, HP, and 3MH was found in the placebo group (p < 0.05), but not in the BCAA group. CONCLUSIONS: The results obtained in this study suggest that swimming induced muscle proteolysis was prevented by BCAA supplementation. The mechanism could be attributed to the availability of ammonia provided by the oxidation of supplemented BCAAs during exercise.

Adult↗
PubMed1987

Decrease in serum testosterone levels with maximal intensity swimming exercise in trained male and female swimmers.

Circulating testosterone levels have generally been reported to increase during short term, intense running or bicycle ergometer exercise. Swimming differs from such activity because of the strenuous arm activity and because it is conducted in a liquid medium in the horizontal position with the weight totally supported. To investigate whether such differences modify the serum testosterone response to exercise, we measured serum testosterone levels before and after a maximal intensity swimming test in ten elite male and ten elite female swimmers. Levels of circulating testosterone fell in 19 of 20 swimmers in contrast to previous reports of exercise in the vertical position. In women mean testosterone levels declined by 39.4% from baseline values and in males, mean testosterone levels declined by 19.0%. Since the incremental protocol was similar to in design to maximal intensity tests conducted on a treadmill or bicycle ergometer, these data suggest that the differing physical circumstances of swimming lead to a qualitatively different testosterone response to exercise.

Adolescent↗
PubMed2002

Effect of a Fast-skin 'body' suit on drag during front crawl swimming.

The effect on drag of a Speedo Fast-skin suit compared to a conventional suit was studied in 13 subjects (6 males, 7 females) swimming at different velocities between 1.0 and 2.0 m.s-1. The active drag force was directly measured during front crawl swimming using a system of underwater push-off pads instrumented with a force transducer (MAD system). For a range of swimming speeds (1.1, 1.3, 1.5 and 1.7 m.s-1), drag values were estimated. On a group level, a statistically non-significant drag reduction effect of 2% was observed for the Fast-skin suit (p = 0.31). Therefore, the 7.5% reduction in drag claimed by the swimwear manufacturer was not corroborated.

Adolescent↗