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PubMed2003

Effect of ginsenosides administered intrathecally on the antinociception induced by cold water swimming stress in the mouse.

We examined the effects of ginseng total saponin (GTS) and several ginsenosides injected intrathecally (i.t.) or intracerebroventricularly (i.c.v.) on the antinociception induced by cold water swimming. The tail-flick response was used as an antinociceptive parameter. We found that i.t. injection of GTS time- and dose-dependently attenuated inhibition of the tail-flick response induced by cold water swimming, although GTS given i.c.v. had no significant effect on the latency of the tail-flick response induced by cold water swimming. To identify those responsible for antagonism of GTS against cold water swimming-induced antinociception, the effects of various kinds of ginsenosides (R(b1), R(b2), R(c), R(d), R(e), and R(g1)) on inhibition of the tail-flick response induced by cold water swimming were examined. R(b1), R(d), R(e), and R(g1) effectively attenuated the inhibition of the tail-flick response induced by cold water swimming stress. Our results suggest that GTS injected spinally, but not supraspinally, reduces the antinociception induced by this stress, and that the responsible ginsenosides against antinociception induced by cold water swimming may be R(b1), R(d), R(e), and R(g1). Moreover, the possible involvement of the opioid system in the regulation of cold water swimming stress-induced antinociception by these four ginsenosides is discussed.

Analgesics↗
PubMed2003

Drafting during swimming improves efficiency during subsequent cycling.

PURPOSE: The aim of the present study was to investigate the effects of drafting (i.e., swimming directly behind a competitor) while swimming with a wet suit on physiological parameters and cadence during subsequent cycling. METHODS: Eight well-trained male triathletes underwent two submaximal sessions conducted in a counterbalanced order. One of these sessions (SAC) consisted of a 750-m swim, performed at competition pace, followed by a 15-min ride on a bicycle ergometer at 75% of maximal aerobic power and at a freely chosen cadence. During the other session (SDC) the subjects swam 750 m in a drafting position at the same pace as during SAC and then performed the 15-min cycling test at the same intensity as during SAC. RESULTS: The main result indicated that cycling efficiency was significantly improved when the cycling session was preceded by a swimming bout performed in drafting position compared with an isolated swimming bout (+4.8%, P < 0.05). CONCLUSION: These results could be partly explained by the lower relative intensity observed during swimming in the SDC trial when compared with the SAC trial. This study suggests the relative importance of swimming condition and highlights the advantage of drafting during the swimming portion of a sprint triathlon.

Adult↗
PubMed1993

REM sleep deprivation potentiates the effects of imipramine and desipramine but not that of clomipramine in the forced swimming test.

Effects of REM sleep (REMs) deprivation on the basal swimming activity and the tricyclic anti-depressants-induced increase in swimming activity in the forced swimming test were investigated. Immediately after a 48-hr period of REMs deprivation, the basal swimming activity in REMs-deprived mice was significantly higher than those in group-housed and socially isolated animals used as the control groups. The REMs deprivation-induced increase in the swimming activity was not changed by adrenoceptor antagonists and it returned to the control levels 3 hr after the REMs deprivation treatment. Moreover, imipramine and desipramine but not clomipramine further increased the swimming activity enhanced by REMs deprivation at doses that did not affect the activity in the control groups. The enhancing effect of REMs deprivation on the sensitivity to imipramine and desipramine remained unchanged even at 3 hr after the REMs deprivation treatment, and it was blocked by the alpha 2-adrenoceptor antagonist yohimbine. These results suggest that the REMs deprivation-induced increase in basal swimming activity in the forced swimming test is not mediated by adrenoceptor mechanisms, whereas the enhancing effect of REMs deprivation on the sensitivity to imipramine and desipramine may be mediated by the functional changes in alpha 2-adrenoceptors in the brain.

Adrenergic alpha-Antagonists↗
PubMed2000

Prolonged swimming exercise training induce hypophosphatemic osteopenia in stroke-prone spontaneously hypertensive rats (SHRSP).

Stroke-prone spontaneously hypertensive rats (SHRSP) induce spontaneous osteoporosis. To elucidate the specific characteristics of bone metabolism, the SHRSP was compared with age matched Wistar-Kyoto (WKY) rats. We investigated the effects of prolonged swimming exercise training on bone mineral density (BMD) and metabolism in the SHRSP. Seven-week-old male SHRSP and WKY were divided into three groups; the sedentary control WKY group (n = 6, WKY), the sedentary control SHRSP group (n = 6, SP) and the swimming exercise training SHRSP group (n = 6, SWIM) (in pool with 60 min./day, 5 days/week for 12 weeks). The femoral BMD, bone mineral content (BMC), strength, Ca and P contents (%) of SHRSP were approximately 17, 27, 25, 20 and 9%, respectively, lower than that of WKY (p < 0.001). Serum alkaline phosphatase (AlP) had not changed between both of SP and WKY, but tartrate-resistant acid phosphatase (TrAcP) of SP approximately 3-fold higher than that of WKY (p < 0.05). Both serum calcium (Ca) and intact parathyroid hormone (i-PTH) were similar between SP and WKY. However, serum phosphate (P) of SP was approximately 18% lower than that of WKY (N.S.). These results suggested that SHRSP induces osteopenia by the bone turnover of the promoted osteoclast activity with disturbed phosphate homeostasis. On the other hand, the femoral BMD and strength were approximately 7% and 20%, respectively, decreased in the SWIM (p < 0.001), and femoral bone Ca and P contents (%) were also approximately 11% and 14%, respectively, lower than that of SP (p < 0.001). There were no significant difference between SWIM and SP on serum Ca, but serum P of SWIM was significantly lower than that of SP (p < 0.05). These results suggested that the prolonged swimming exercise training in the SHRSP induces more cruelly hypophosphatemia, and leading to osteopenia eventually. We conclude that SHRSP induces osteopenia with disturbance of phosphate homeostasis, and the prolonged swimming exercise in the SHRSP might deteriorate hypophosphatemia and osteopenia.

Animals↗
PubMed1999

Muscle activity in steady swimming scup, Stenotomus chrysops, varies with fiber type and body position.

The red and pink aerobic muscle fibers are used to power steady swimming in fishes. We examined red and pink muscle recruitment and function during swimming in scup, Stenotomus chrysops, through electromyography and high-speed ciné. Computer analysis of electromyograms (EMGs) allowed determination of initial speed of muscle recruitment and duty cycle and phase of muscle electromyographic activity for both fiber types. This analysis was carried out for three longitudinal positions over a range of swimming speeds. Fiber type and longitudinal position both affected swimming speed of initial recruitment. Posterior muscle is recruited at the lowest swimming speed, whereas more anterior muscle is not initially recruited until higher speeds. At more anterior positions, the initial recruitment of pink muscle occurs at a higher swimming speed than the recruitment of red muscle. The duty cycle of pink muscle EMG activity is significantly shorter than that of red muscle, reflecting a difference in the onset time of activation during each cycle of length change: pink muscle onset time follows that of red. The different patterns of usage of red and pink muscle reflect differences in their contraction kinetics. Because pink muscle generates force more rapidly than red muscle, it can be activated later in each tailbeat cycle. Pink muscle is used to augment red muscle power production at higher swimming speeds, allowing a higher aerobically based steady swimming speed than that possible by red muscle alone.

Animals↗
PubMed2002

The effect of swimming on cartilage formation.

Swimming is a non-weight-bearing exercise. Therefore it has the advantage of maintaining skeletal integrity in aged persons with weakened skeletal structures. Unlike other weight-bearing aerobic exercises, however, it does not appear to exert sufficient stimulus on bone-remodeling activities because the local load-bearing on bone tissues is mild. The purpose of this study was to investigate the effect of swimming on bone remodeling, especially with the use of implanted pellets containing bone morphogenetic protein (BMP) and demineralized bone matrix during the initial stages of the differentiation of mesenchymal cells to cartilage cells. Six-week-old female rats were divided into the swimming group and a control, nonswimming group. Test animals were forced to swim in a water bath for 30 min daily for 2 wk. After the swimming protocol, pellets were implanted and harvested. Messenger RNA isolated from pellets was quantified by means of a reverse transcription-polymerase chain reaction. The expression of RNAs for bone sialoprotein and BMP-6 in pellets from the swimming group was apparently enhanced at 7 d after implantation. These results suggested that systemic hormonal and/or metabolic changes that promote cartilage formation might have occurred after swimming because the effect was observed after the swimming protocol had ended and the pellets were implanted at a non-weight-bearing site.

Animals↗
PubMed1999

The validity of ratings of perceived exertion for cross-modal regulation of swimming intensity.

BACKGROUND: This study examined the use of Borg's category Ratings of Perceived Exertion (RPE) scale for prescribing and self-regulating swimming intensity. Subjects were males and females (n = 19) ages nineteen to fifty-eight who regularly swam for fitness. EXPERIMENTAL DESIGNS: Subjects completed six trials. Each trial was separated by a minimum of forty-eight hours. Mean cycle ergometry heart rates at estimated RPE-overall 12 and 16 were compared to mean swimming heart rates at produced RPE-overall 12 and 16. Also, mean arm ergometry heart rates at estimated RPE-arms 12 and 16 were compared to mean swimming heart rates at produced RPE-arms 12 and 16. Cycling and arm ergometry anchor trials familiarized subjects with testing protocol and Borg's scale prior to estimation and production trials. Comparisons were made using a one-way ANOVA (alpha 0.05). RESULTS: Mean cycling heart rate at RPE-overall 16 was not significantly different from mean swimming heart rate at RPE-overall 16. Mean swimming heart rate was significantly greater than cycling heart rate at RPE-overall 12. Mean swimming heart rates at RPE-arms 12 and 16 were significantly greater than arm ergometry heart rates at RPE-arms 12 and 16. CONCLUSIONS: Results suggest that RPE-overall 16 may be useful in prescribing a higher exercise intensity for swimmers. However, adjustments from RPE-overall 12 are needed for establishing a lower intensity. Additionally, arm ergometry-based RPEs may require adjustments to be effective in prescribing and regulating swimming intensity. Results suggest that cycling and arm ergometry anchored RPE responses should be used with discretion when prescribing and regulating swimming intensity.

Adult↗
PubMedDate not supplied

[Activity and properties of phosphofructokinase from while muscle of the horse mackerel Trachurus mediterraneus during simulation due to swimming].

The activity and properties of phosphofructokinase (PFK) in tissues of horse mackerel which was swimming at burst regimen for 5 min and at cruiser one for 60 min have been investigated. In white muscle the PFK activity increased 1.6-fold after burst swimming and Hill's coefficient rose as well and decreased 3-fold after cruiser one. Swimming did not change the half-maximal saturation constant for both substrates and inhibition constants for ATP and citrate. In the preparations from white muscle of fish which were stimulated by burst swimming the PFK activity at physiological pH values (6.0-7.0) was higher comparing with one from the control group and after cruiser swimming. Incubation of preparations at 45 degrees C decreased the activity of PFK in control and cruiser swimming groups (to 61-67% of initial level) and increased it after burst swimming (1.3-fold). The mechanisms involving in stable modification of PFK under different swimming regimens are discussed.

Animals↗
PubMed2003

Circuitry underlying regulation of the serotonergic system by swim stress.

The dorsal raphe nucleus (DR)-serotonin (5-HT) system has been implicated in depression and is dramatically affected by swim stress, an animal model with predictive value for antidepressants. Accumulating evidence implicates the stress-related neuropeptide corticotropin-releasing factor (CRF) in the effect of swim stress on this system. This study investigated neural circuits within the DR that are activated by swim stress as revealed by neuronal expression of the immediate early gene, c-fos. Swim stress increased c-fos expression in the dorsolateral subregion of the DR. The majority of c-fos-expressing neurons were doubly labeled for GABA (85 +/- 5%), whereas relatively few were immunolabeled for 5-HT (4 +/- 1%), glutamate (0.5 +/- 0.3%) or calbindin (1.5 +/- 0.3%). Dual immunohistochemical labeling revealed that c-fos-expressing neurons in the dorsolateral DR were enveloped by dense clusters of CRF-immunoreactive fibers and also contained immunolabeling for CRF receptor, suggesting that c-fos-expressing neurons in the DR were specifically targeted by CRF. Consistent with this, the CRF receptor 1 antagonist, antalarmin, prevented swim-stress-elicited c-fos expression in the dorsolateral DR. Together with previous findings that both swim stress and CRF decrease 5-HT release in certain forebrain regions, these results suggest that swim stress engages CRF inputs to GABA neurons in the dorsolateral DR that function to inhibit 5-HT neurons and 5-HT release in the forebrain. This circuitry may underlie some of the acute behavioral responses to swim stress as well as the neuronal plasticity involved in long-term behavioral changes produced by this stress.

Animals↗
PubMed2004

Poor-quality water in swimming pools associated with a substantial risk of otitis externa due to Pseudomonas aeruginosa.

There are many large and small public outdoor and indoor swimming pools in Tehran that hundreds of people use, especially on hot summer days. The bacteriological quality of the water of some of these pools was assayed over a period of about one year (2001-2002). To assess if these swimming pools were a health risk to users, eleven public swimming pools, in the east and northeast of the city, were examined, and the exposed people were monitored. Samples of swimming-pool waters were examined for colony counts, Escherichia coli and coliforms. In addition, Pseudomonas aeruginosa was isolated from nine (81.8%) of those pools. P. aeruginosa grew in seven (63.6%) of the swimming-pool water samples. In two (18.2%) other samples, in addition to P. aeruginosa, high rates of total bacterial count, total coliforms and faecal coliform counts were also found. At the same time, users of the swimming pools were asked to complete a questionnaire. Ear swabs were collected from 179 users with a history of ear problems during the previous two weeks. An adequate control group was chosen randomly from those who never used the investigated pools. P. aeruginosa was isolated from the ear swabs of 142 (79.3%) of the cases, as well as from 4% of the controls. Results were matched for age, sex, duration of time spent in the pools, place of occurrence and other useful information. Investigation of the contaminated swimming pools revealed that chlorination was often inadequate, especially when high numbers of people led to overuse of the pools. Although the results of this research showed that otitis externa was strongly associated with the swimming pools, due to P. aeruginosa, an extensive follow-up study is needed to determine the other possible health risks associated with public pools.

Adolescent↗
PubMedDate not supplied

[Patterns of swimming of cercariae in some trematode species].

Swimming activity of cercariae in the trematode species Cryptocotyle lingua, Himasthla elongata, Maritrema subdolum, and Cercaria parvicaudata (Renicola sp.) is studied using video microfilming. The larvae of C. lingua demonstrate a typical intermittent swimming with regularly alternating periods of active movement and passive floating. The duration of both periods during the first 30 min of cercaria's life retains equal, and later the passive period becomes longer. In 15 h the duration of the active period is 0.5-1 s and the passive one--20-30 s. The cercariae of H. elongata during the first 10-15 min of their free life make short stops (1-2 s) in every 10-15 s of swimming. Later these stops become rare and their duration reduces to 0.5-1 s. The cercariae of M. subdolum and C. parvicaudata are continuous swimmers, having left the molluscan host they move persistently. If stops take place they are very rare (one case in 5-15 min) and very short (0.5-1 s). The movements of cercariae body and their tail during swimming are similar in all species studied. The proximal part of the tail undulates in lateral plane, and the middle and distal parts of this organ in the top view circumscribe a figure of eight. In the side view the middle and distal parts of the tail being rotate form a figure like a screw. The cercariae move along the screw axis. The linear swimming rate in the beginning of cercariae's life is 4.8 mm/s for C. lingua, 2.4 mm/s for H. elongata, and 0.35 mm/s for M. subdolum and C. parvicaudata. By the aging the cercariae swimming rate decreases down to the full cease of swimming activity, and the larvae sediment onto the bottom. The age dynamics of swimming rate is different in cercariae of different species and is determined by the morphological functional features of the larvae.

Animals↗
PubMed1992

Swimming physiology.

Swimming takes place in a medium, that presents different gravitational and resistive forces, respiratory conditions and thermal stress compared to air. The energy cost of propulsion in swimming is high, but a considerable reduction occurs at a given velocity as result of regular swim training. In medley swimmers the energy cost is lowest for front crawl, followed by backstroke, butterfly and breast-stroke. Cardiac output is probably not limiting for performance since swimmers easily achieve higher values during running. Maximal heart rate, however, is lowered by approx. 10 beats/min during swimming compared to running. Most likely active muscle mass is smaller and rate of power production lesser in swimming. Local factors, such as peripheral circulation, capillary density, perfusion pressure and metabolic capacity of active muscles, are important determinants of the power production capacity and emphasize the role of swim specific training movements. Improved swimming technique and efficiency are likely to explain much of the continuous progress in performance. Rational principles based on improved understanding of the biomechanics and physiology of swimming should be guidelines for swimmers and coaches in their efforts to explore the limits of human performance.

Energy Metabolism↗
PubMedDate not supplied

Melatonin supplementation to rats subjected to acute swimming exercise: Its effect on plasma lactate levels and relation with zinc.

OBJECTIVE: The objective of the present study is to examine the effect on melatonin supplementation on plasma lactate levels and its relation with zinc in rats subjected to acute swimming exercise. METHODS: Thirty adult male rats of Spraque-Dawley species were allocated to 3 groups, each containing an equal number of rats: general control group which was not subjected to any procedure (Group 1), the group which was subjected to 30 minutes acute swimming exercise (Group 2), and the group which was subjected to 30 minutes acute swimming exercise after 4-week intraperitoneal (i.p.) melatonin (3 mg/kg/day) supplementation. Lactate and zinc levels in the plasma were studied in the blood samples taken from the experimental animals by decapitation method. RESULTS: The animals in the control group, which was not subjected to any procedure (group 1), had higher lactate levels than those in groups 2 and 3 (p<0,05). Lactate levels in the swimming group supplemented with melatonin (group 3) were lower than those in group 2 (swimming group) (p<0,05). The highest plasma zinc levels were obtained in the melatonin-supplemented swimming group (group 3) (p<0,05). Group 2 (swimming control) had the lowest plasma zinc levels (p<0,05). CONCLUSION: Results of the study demonstrate that melatonin supplementation to rats subjected to acute swimming exercise reduces lactate levels, thereby delaying exhaustion. Increased zinc levels may be mediating this melatonin effect.

Animals↗
PubMed1991

Urine protein excretion and swimming events.

To determine total urinary protein, albumin (ALB), and beta 2-microglobulin (beta 2m) excretion rates in relation to different speeds, 12 males were studied while swimming distances of 100, 600, and 2,000 m at maximal speed. Venous blood lactate concentrations rose to 16.1, 11.6, and 4.5 mmol.l-1 after the 100, 600, and 2,000 m events, while plasma volumes were reduced by 11.3, 7.7, and 5.5%, respectively. ALB urine excretion increased to 110-120 micrograms.min-1 after the 100 and 600 m swims and to 56 micrograms.min-1 after 2,000 m (resting values: 9 micrograms.min-1). In the meantime, the beta 2m excretion rate increased 21 and 10 times the resting values, respectively, for the two shorter swims, with no change for the longer one. Progressive plasma volume reduction was associated with the increase of the protein excretion rate. As evidenced by the creatinine clearance, the glomerular filtration rate did not change for the 100 m swim but dropped by 23 and 35% for the 600 and 2,000 m ones, respectively. On the other hand, the ALB clearance increases were elevated for the three swims, while the beta 2m clearance increases were inversely related to the swimming speeds. The data showed a relationship between the rate of protein excretion and the speed of the swim, and the reduction of plasma volume. The findings could indicate a renal glomerular alteration, with an additional dysfunction of the tubular reabsorption process when the exercise load is high during swimming events.

Albuminuria↗
PubMed1989

Electrophysiology of the swimming system of hydromedusae and the effects of atropine-induced crumpling.

1. In order to evaluate how crumpling behavior influences the swimming system in Liriope tetraphylla, extracellular recordings of muscle action potentials related to both behaviors were performed. 2. The swimming pattern of Liriope consists of irregular bursts of muscle potentials. A correlation was obtained between number of muscle potentials and burst length and between burst and interburst periods. The swimming pattern could be predicted from the burst length since a long burst was followed by a short period of quiescence and by a burst as long as the preceding one. 3. The addition of atropine to induce radial muscle contraction first caused an increase in swimming activity and then an irreversible reduction. The enhancement of swimming activity was due to the increase of burst length and of the frequency of swimming bursts (due to the decrease of the interburst period), and the reduction of swimming activity, to the enhancement of the interburst period and to the reduction of the burst length. 4. It is proposed that, when facing a noxious stimulus, Liriope will first "escape" from it by enhancing its swimming activity and, if the stimulus persists, blockade of the pacemaker system becomes accentuated as the radial muscle contractions become more sustained.

Animals↗
PubMed1985

Swimming activity in marine fish.

Marine fish are capable of swimming long distances in annual migrations; they are also capable of high-speed dashes of short duration, and they can occupy small home territories for long periods with little activity. There is a large effect of fish size on the distance fish migrate at slow swimming speeds. When chased by a fishing trawl the effect of fish size on swimming performance can decide their fate. The identity and thickness of muscle used at each speed and evidence for the timing of myotomes used during the body movement cycle can be detected using electromyogram (EMG) electrodes. The cross-sectional area of muscle needed to maintain different swimming speeds can be predicted by relating the swimming drag force to the muscle force. At maximum swimming speed one completed cycle of swimming force is derived in sequence from the whole cross-sectional area of the muscles along the two sides of the fish. This and other aspects of the swimming cycle suggest that each myotome might be responsible for generating forces involved in particular stages of the tail sweep. The thick myotomes at the head end shorten during the peak thrust of the tail blade whereas the thinner myotomes nearer the tail generate stiffness appropriate for transmission of these forces and reposition the tail for the next cycle.

Action Potentials↗
PubMed1983

The acute effects of controlled breathing swimming on glycolytic parameters.

Hypoxic Training, which has been popular in swimming for the past few years, is more correctly called Controlled Breathing Swimming (CBS). This study investigated the acute effects of CBS on blood glucose (GL), lactate (LA), pH, PvCO2, and recovery oxygen uptake. Six male swimmers were studied in two separate swimming sessions using two breathing patterns--free breathing (FB), and 7-stroke breathing (7B). For each session venous blood samples were drawn prior to the swim (Rest), immediately after the swim (IA), and during the 6th minute of recovery (6-R). Analyses for GL, LA, pH, and PvCO2 were carried out, and recovery VO2 (20 minutes) was calculated. Significant increased due to the exercise sessions themselves were found in both GL (p less than 0.05), and LA (p less than 0.05) concentrations. Between the two swim protocols, no significant difference was observed except for a significantly greater % CO2 production after the 7B swim (p less than 0.05). These results indicated that the acute CBS did not induce more glycolytic metabolic activity than did the normal swimming protocol.

Adolescent↗
PubMed1976

Shigellosis from swimming.

In Augsut 1974, 31 of 45 cases of Shigella sonnei infection in Dubuque, Iowa, were traced to swimming in an 8-km stretch of the Mississippi River. Comparison of the first case in each affected family with neighborhood controls showed a significant correlation between swimming and illness (P less than .0001). A significant association between diarrheal illness and swimming (P less than .0001) was also demonstrated by a retrospective survey of 60 families who had camped at a park beside the river; the attack rate for swimmers who got water in their mouths while swimming was 18%. They had been swimming in water where the mean fecal coliform count was 17,500 organisms per 100 ml; the federal recommended upper limit for swimming water is 200 per 100 ml. A water sample obtained at the park swimming area one month after authorities had banned swimming in the area yielded S sonnei with the same antibiogram, colicin type, and phage type as the isolates from six swimmers.¿

Child↗