Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “SWIMMING”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 739 records · Page 41Linked to original sources
PubMed2001

Forced swimming stimulates the expression of vasopressin and oxytocin in magnocellular neurons of the rat hypothalamic paraventricular nucleus.

Previous studies have shown that a 10-min forced swimming session triggers the release of both vasopressin and oxytocin into the extracellular fluid of the hypothalamic paraventricular (PVN) and supraoptic nuclei (SON) in rats. At the same time oxytocin, but not vasopressin, was released from the axon terminals into the blood. Here we combined forced swimming with in situ hybridization to investigate whether (i) the stressor-induced release of vasopressin and oxytocin within the PVN originates from parvo- or magnocellular neurons of the nucleus, and (ii) central release with or without concomitant peripheral secretion is followed by changes in the synthesis of vasopressin and/or oxytocin. Adult male Wistar rats were killed 2, 4 or 8 h after a 10-min forced swimming session and their brains processed for in situ hybridization using 35S-labelled oligonucleotide probes. As measured on photo-emulsion-coated slides, cellular vasopressin mRNA concentration increased in magnocellular PVN neurons 2 and 4 h after swimming (P < 0.05). Similarly, oxytocin mRNA concentration was significantly increased in magnocellular neurons of the PVN at 2 and 8 h (P < 0.05). We failed to observe significant effects on vasopressin and oxytocin mRNA levels in the parvocellular PVN and in the SON. Taken together with results from previous studies, our data suggest that magnocellular neurons are the predominant source of vasopressin and oxytocin released within PVN in response to forced swimming. Furthermore, in the case of vasopressin, central release in the absence of peripheral secretion is followed by increased mRNA levels, implying a refill of depleted somato-dendritic vasopressin stores. Within the SON, however, mRNA levels are poor indicators of the secretory activity of magnocellular neurons during stress.

Animals↗
PubMed2002

Forced swimming triggers vasopressin release within the amygdala to modulate stress-coping strategies in rats.

Previously, we have demonstrated that forced swimming triggers the release of arginine vasopressin (AVP) within the septum of rats, where AVP modulates stress-coping strategies. The present study was designed to examine the effects of forced swimming on the release of AVP within the amygdala. Therefore, adult male Wistar rats were chronically implanted with a microdialysis probe aimed at the amygdala to monitor the local release of AVP under both resting and stress conditions. A 10-min forced swimming session caused a significant increase in the extracellular AVP concentration (to 366 +/- 90% of baseline; P < 0.05) within this brain area. In a subsequent experiment we investigated the physiological impact of the stressor-induced release of AVP by administrating the AVP V1 receptor antagonist d(CH2)5Tyr(Me)AVP into the amygdala via inverse microdialysis. Bilateral antagonist treatment modulated the behavioural response acutely by increasing the time the animals spent struggling and by reducing the time the animals floated. Our results demonstrate a significant activation of the vasopressinergic system within the amygdala in response to forced swimming. AVP released within the amygdala seems to be involved in the generation of passive coping strategies in stressful situations. Taken together with previous findings the results of the present study suggest that AVP is released within septum and amygdala to balance the behavioural response during forced swimming.

Adaptation, Psychological↗
PubMed2001

Adrenoreceptor-mediated modulation of the spinal locomotor pattern during swimming in Xenopus laevis tadpoles.

This study focused on the contribution of different adrenoreceptor subtypes to the modulation of fictive swimming activity in a relatively simple, yet intact, lower vertebrate system, the immobilized Xenopus laevis tadpole and explored their possible role in mediating the noradrenergic modulation of spinal motor networks. In Xenopus embryos, near the time of hatching, activation of alpha(1) adrenoreceptors increased the duration of episodes of fictive swimming, whilst in larvae, 24 h after hatching, they were decreased. Activation of alpha(2) adrenoreceptors, however, markedly reduced episode duration at both developmental stages. Cycle periods in both stages were increased by the activation of alpha(1) and/or alpha(2) receptor subclasses, whereas beta adrenoreceptors were not apparently involved in the modulation of cycle periods or the duration of swim episodes. However, both beta and alpha(1) receptor activation decreased the intersegmental delay in the head-to-tail propagation of swimming activity, while alpha(2) receptors did not influence these rostro-caudal delays. Activation of neither alpha, nor beta, receptor subclasses had any consistent effect on the duration of ventral motor bursts. Our findings suggest that noradrenergic modulation of the swim-pattern generator in Xenopus tadpoles is mediated through the activation of alpha and beta adrenoreceptors. In addition, activation of particular receptor subclasses might enable the selective modulation of either the segmental rhythm generating networks, the intersegmental coordination of those networks or control at both levels simultaneously.

Adrenergic alpha-Agonists↗
PubMed2006

Alterations in antioxidant status, protein concentration, acetylcholinesterase, Na+, K+-ATPase, and Mg2+-ATPase activities in rat brain after forced swimming.

The aim of this study was to investigate whether exercise stress (short [2 h] or prolonged [5 h] forced swimming in rats) could modulate brain total antioxidant status (TAS), tissue protein concentration, and the activities of acetylcholinesterase (AChE), Na +, K +-ATPase, and Mg 2+-ATPase. Protein concentration, TAS and enzyme activities in homogenized rat brain were determined spectrophotometrically. Protein concentration was decreased by 15 % (p < 0.01) and by 30 % (p < 0.001) after 2 h and 5 h of forced swimming, respectively. TAS was decreased by 20 - 25 % after 2 h or 5 h of exercise. AChE was inhibited by 30 % (p < 0.001) and 45 % (p < 0.001) after 2 h and 5 h of forced swimming, respectively. In contrast, Na +, K +-ATPase and Mg 2+-ATPase were stimulated by 80 % (p < 0.001) and 40 % (p < 0.001), respectively, after 2 h of swimming and by 100 % (p < 0.001) and 60 % (p < 0.001), respectively, after 5 h of exercise. Control values in nontreated rats were unaltered (p > 0.05). In conclusion, short or prolonged forced swimming induces oxidative stress in rats, probably resulting in a reduction in brain protein concentration and AChE activity. In addition, a Na +, K +-ATPase and Mg 2+-ATPase activation was observed under the above mentioned experimental conditions. This stress condition may modulate brain intracellular Mg 2+ concentration, neural excitability, metabolic energy production, and neurotransmission.

Acetylcholine↗
PubMed1990

Effects of warm-up on blood gases, lactate and acid-base status during sprint swimming.

A standardized 200-m front crawl sprint swim (SpS) was used to evaluate the effects of warm-up on pH, blood gases, and the concentrations of lactate ([La-]) and bicarbonate ([HCO3-]) in arterialized and venous blood. Eight trained male swimmers performed two randomly assigned 200-m front crawl swims at previously determined intensities corresponding to 120% VO2max. One swim was preceded by a warm-up (WU trial) which consisted of a 400-m front crawl swim (82% VO2max), 400-m flutter kicking (45% VO2max), and 4 x 50-m front crawl sprints (111% VO2max). The second was performed without warm-up (NWU trial). Blood was sampled from a hyperemized earlobe and an antecubital vein before the warm-up, 9 min after the warm-up (1 min before the swim), immediately following the SpS, and at 2, 5, 10, and 20 min after the SpS. The warm-up exercise resulted in a higher pre-SpS [La-] in arterialized blood (3.1 +/- 0.4 and 1.7 +/- 0.4 mmol x l-1, p less than 0.05), a higher hydrogen ion concentration ([H+]) in venous blood (45.9 +/- 0.9 and 42.2 +/- 0.8 nmol x l-1, p less than 0.001), and a lower arterialized blood [HCO3-] (25.1 +/- 0.9 and 22.2 +/- 0.8 mmol x l-1, p less than 0.05). The SpS was accompanied with higher heart rates during the WU trial (178 +/- 3 and 169 +/- 3 bpm; p less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1997

Heart rate response to submaximal and maximal workloads during running and swimming.

The purpose of the present study was to determine if common indexes of exercise intensity, assessed with land-based exercise, could be applied to swimming. Consequently, the heart rate (HR) and oxygen uptake (VO2) responses to submaximal and maximal treadmill running (TR) and free swimming (SW) in 11 fitness swimmers were assessed to determine if the responses to TR could be used to predict those of SW. A maximal graded exercise test using a discontinuous protocol was used for TR, while four graded submaximal 200 yd swims and one 400 yd maximal swim was used for SW. Rest periods were similar for each mode. Significantly lower (p < 0.05) peak values were found in SW compared to TR for both HR (174 +/- 3 vs 183 +/- 3 bt x min(-1)) and VO2 (3.58 +/- 0.18 vs 3.97 +/- 0.22 L x min(-1)), SW vs TR; +/- SE, respectively. However, regression analyses of submaximal HR vs VO2 for each subject revealed similar slopes for TR and SW (30.5 +/- 1.7 vs 29.9 +/- 3.5 bt x L(-1), p > 0.05) and similar intercepts (67.3 +/- 2.6 vs 66.5 +/- 11.5 bt x min(-1), p > 0.05). At the VO2 equivalent to 50% treadmill VO2max, the heart rate predicted from SW did not differ significantly from TR (118 +/- 5 vs 124 +/- 1 bt x min(-1), p > 0.05). This was also true at 85% treadmill VO2max (171 +/- 4 vs 166 +/- 3 bt x min(-1), SW vs TR, respectively; p > 0.05). These data suggest that peak heart rate and oxygen uptake appear to be mode specific, but exercising at a given submaximal oxygen uptake will elicit a similar heart rate regardless of the mode. Thus, target heart rate ranges designed for land-based exercise appear to be appropriate for fitness swimmers during swimming.

Adult↗
PubMed2006

Backyard swimming pool safety inspections: a comparison of management approaches and compliance levels in three local government areas in NSW.

ISSUE ADDRESSED: Since 1992, swimming pool fencing has been a legislative requirement in New South Wales (NSW), yet compliance with the NSW Swimming Pool Act is mixed. Local councils are responsible for the enforcement of the act. However, their approach to enforcement and the management of backyard swimming pool safety inspections is varied. METHODS: A random sample of backyard swimming pools was inspected in Council A and existing compliance data for pools in two other councils (B and C) were obtained. Pool owners in Council A were surveyed regarding their attitudes to pool fencing and inspections. Semi-structured interviews were conducted with council employees. RESULTS: Pool compliance rates across the three council areas varied. In Councils A and C, 51% and 54% of pools, respectively, were found to be non-compliant at the first inspection. Following re-inspection in Council A of 227 pools, a further 125 pools reached compliance. In Council B, 97% of the inspected pools were compliant. CONCLUSIONS: This study provides evidence of poor backyard swimming pool safety compliance where local government inspection activity is minimal or non-existent.

Building Codes↗
PubMed2006

Swimming Paramecium in magnetically simulated enhanced, reduced, and inverted gravity environments.

Earth's gravity exerts relatively weak forces in the range of 10-100 pN directly on cells in biological systems. Nevertheless, it biases the orientation of swimming unicellular organisms, alters bone cell differentiation, and modifies gene expression in renal cells. A number of methods of simulating different strength gravity environments, such as centrifugation, have been applied for researching the underlying mechanisms. Here, we demonstrate a magnetic force-based technique that is unique in its capability to enhance, reduce, and even invert the effective buoyancy of cells and thus simulate hypergravity, hypogravity, and inverted gravity environments. We apply it to Paramecium caudatum, a single-cell protozoan that varies its swimming propulsion depending on its orientation with respect to gravity, g. In these simulated gravities, denoted by f(gm), Paramecium exhibits a linear response up to f(gm) = 5 g, modifying its swimming as it would in the hypergravity of a centrifuge. Moreover, experiments from f(gm) = 0 to -5 g show that the response is symmetric, implying that the regulation of the swimming speed is primarily related to the buoyancy of the cell. The response becomes nonlinear for f(gm) >5 g. At f(gm) = 10 g, many paramecia "stall" (i.e., swim in place against the force), exerting a maximum propulsion force estimated to be 0.7 nN. These findings establish a general technique for applying continuously variable forces to cells or cell populations suitable for exploring their force transduction mechanisms.

Animals↗
PubMed1998

Observational learning and the fearful child: influence of peer models on swimming skill performance and psychological responses.

This study examined the role of peer mastery and coping models on children's swimming skills, fear, and self-efficacy. Children (N = 24; M age = 6.2 years), who were identified as fearful of the water, were matched to control, peer-mastery, or peer-coping model conditions. Day 1 included a preintervention assessment. Days 2-4 included exposure to model conditions followed by a 20-min swimming lesson, Day 5 consisted of postintervention assessments, and a follow-up test was conducted 4 days later. Data were analyzed in a series of 3 x 3 (Model Type x Assessment Period) repeated measures analyses of variance on the dependent variables. Results revealed differences between modeling and control groups at postintervention and follow-up, but the small sample size and large within-group variability compromised many statistically significant findings. Calculation of effect sizes indicated moderate-to-large pre- to posintervention differences between control and modeling groups on skill, self-efficacy, and fear of swimming. These findings suggest that a modeling intervention combined with swimming lessons is a more effective behavior change agent for fearful children than swimming lessons alone.

Adaptation, Psychological↗
PubMed2003

Baby swimming increases the risk of recurrent respiratory tract infections and otitis media.

AIM: To estimate the association between baby swimming and recurrent respiratory tract infections and otitis media in the first year of life in children of parents without and with atopy. METHODS: Norwegian schoolchildren (n = 2862) was enrolled in a cross-sectional study of asthma and allergy using the questionnaire of the International Study of Asthma and Allergies in Childhood (ISAAC). The outcomes were parental retrospective report of recurrent respiratory tract infections and otitis media diagnosed by a physician in the first year of life. The exposure was baby swimming during the same period. Parental atopy reflects a history of maternal or paternal asthma, hayfever or eczema. RESULTS: The prevalence of recurrent respiratory tract infections was higher (12.3%) among children who took part in baby swimming than among those who did not (7.5%). The prevalence of recurrent respiratory tract infections during the first year of life was 5.6% and 10.5%, respectively, in children of parents without and with atopy, whereas the prevalence of baby swimming was 5.6% and 5.1%, respectively, in the two groups. Stratified analysis using parental atopy as strata showed that the increased risk of recurrent respiratory tract infections was only present among children of parents with atopy [adjusted odds ratio (aOR) 2.08, 95% confidence interval (95% CI) 1.08-4.031. A similar trend was present for otitis media (aOR 1.77, 95% CI 0.96-3.25). CONCLUSION: The results of this study suggest that baby swimming and infant respiratory health may be linked. The findings need to be examined in a longitudinal study.

Child↗
PubMed2003

Bacteriological and chemical quality of swimming pools water in developing countries: a case study in the West Bank of Palestine.

Monitoring was carried out during summer 2000 in all the swimming pools in the West Bank of Palestine. Fifty-eight water samples, collected from 46 swimming pools, were examined for Coliforms and bacterial species including Streptococci, Salmonellae, and Staphylococcus. Salmonellae were isolated in 21 out of 23 samples. All of the examined samples from the swimming pools water were unacceptable according to the Palestinian and WHO standards. Extensive efforts are required to improve the water quality of the swimming pools in the West Bank, mainly public awareness, training of governmental inspectors, operators and owners of the swimming pools, in addition to a strict system for monitoring of the water quality.

Developing Countries↗
PubMed2003

Effectiveness and safety of a structured swimming program in previously sedentary women during pregnancy.

OBJECTIVE: To determine whether undertaking a swimming program in sedentary women during pregnancy would improve maternal fitness without adverse fetal consequences. METHODS: Prospective observational investigation of healthy sedentary pregnant women participating in a monitored swimming program. RESULTS: Twenty-three women attended swimming sessions from 16 to 28 weeks of gestation resulting in increasing distances swum and improved aerobic fitness as measured by physical work capacity (PWC170) (p = 0.003). Resting maternal heart rate decreased (p = 0.041) and resting systolic (p = 0.092) and diastolic (p = 0.971) blood pressures remained unchanged over gestation. The mean fetal heart rates decreased with advancing gestational age (p = 0.001), consistent with normal physiology. Non-stress tests and umbilical artery systolic/diastolic ratios were similar before and after swimming sessions, providing evidence that fetal well-being was unchanged. CONCLUSIONS: A structured swimming program in sedentary pregnant women increases maternal fitness without any alteration in maternal and fetal well-being.

Adult↗
PubMed2004

Swim training increases ovalbumin induced active systemic anaphylaxis in mice.

Aerobic training can be defined as any physical exercise that increases the heart rate and enhances the body's intake of oxygen long enough to benefit the condition of the body. Running, cycling, and swimming are examples of aerobic activities. In recent years, the importance of sports in everyday life has been rapidly increasing. Moderate exercise appears to stimulate the immune system. However, healthy elite runners often complain about bronchial symptoms after heavy exercise. Exercise-induced asthma and active systemic anaphylaxis are the most common problems seen in these individuals. The inter-relationship of exercise and the allergy response has not been well studied. This study was designed to examine the effects of regular swim training on body weight, spleen index, the number of lymphocytes, scoring of active systemic anaphylactic shock, proliferative activity of splenic lymphocytes and cytokine levels in BALB/c mice. Thirty mice (6 weeks old) were involved in this study and they were divided into 3 groups: a control group (Control, n = 10), a sensitized group (Sensitized, n = 10), and a sensitized-trained group (Sen-trained, n = 10). The sen-trained group was studied after 10 weeks of regular swim training. All data were expressed as mean and standard deviation by using SPSS (ver.10.0). The swim training caused a decrease in body weight (p < 05), an increase of spleen index, active systemic anaphylaxis, lymphocyte proliferation (stimulated with ovalbumin), and cytokine levels (especially IL-4) when comparing the sen-trained group to the sensitized group (p < .05). These data indicate that there is a link between allergy anaphylaxis and regular swim training. This may be due to increased lymphocyte proliferation (stimulated with ovalbumin), ASAS (active systemic anaphylactic shock) score, and IL-4 cytokine levels after exercise.

Anaphylaxis↗
PubMed1961

The fine structure of the cilia from ctenophore swimming-plates.

The ctenophore swimming-plate has been examined with the electron microscope. It has been recognized as an association of long cilia in tight hexagonal packing. One of the directions of the hexagonal packing is parallel to the long edge of the swimming-plate and is perpendicular to the direction of the ciliary beat. All the cilia in the swimming-plate are identically oriented. The effective beat in the movement of the swimming-plate is directed towards the aboral pole of the animal, and this is also the side of the unpaired peripheral filament in all the cilia. The direction of the ciliary beat is fixed in relation to the position of the filaments of the cilia. The swimming-plate cilium differs from other types of cilia and flagella in having a filament arrangement that can be described as 9 + 3 as opposed to the conventional 9 + 2 pattern. The central filaments appear in a group of two "tubular" filaments and an associated compact filament. The compact filament might have a supporting function. It has been called "midfilament." Two of the peripheral nine filaments (Fig. 1, Nos. 3 and 8) are joined to the ciliary membrane by means of slender lamellae, which divide the cilium into two unequal compartments. These lamellae have been called "compartmenting lamellae." Some observations of the arrangement of the compartmenting lamelae indicate that they function by cementing the cilia together in lateral rows. The cilia of the rows meet at a short distance from each other, leaving a gap of 30 A only. The meeting points are close to the termini of the compartmenting ridges. An electron-dense substance is sometimes seen bridging the gap. Some irregularities are noted with regard to the arrangement of the compartmenting lamellae particularly at the peripheral rows of cilia. In many cilia in these rows there are small vesicles beneath the ciliary membrane.

Animals↗
PubMedDate not supplied

Effect of ontogenetic increases in body size on burst swimming performance in tadpoles of the striped marsh frog, Limnodynastes peronii.

The effect of ontogenetic increases in total length on burst swimming performance was investigated in tadpoles of the striped marsh frog (Limnodynastes peronii) over the total-length range of 1. 5-4 cm and Gosner developmental stages 25-38. The burst swimming performance of tadpoles at 10 degrees and 24 degrees C was determined by videotaping startle responses with a high-speed video camera at 200 Hz and analysing the sequences frame by frame. Maximum swimming velocity (Umax) and acceleration (Amax) increased with total length (L) at a rate that was proportionally greater than the increase in total length (i.e., positive allometry; exponents >1) and was described by the allometric equations Umax=0.061L1.34 and Amax=1.15L1.11 at 10 degrees C and Umax=0.114L1.34 and Amax=1.54L1. 11 at 24 degrees C. Stride length increased with a total-length exponent of approximately 1 but was unaffected by temperature. Tail-beat frequency was not affected by total length and increased from 7.8+/-0.2 Hz at 10 degrees C to 21.7+/-0.7 Hz at 24 degrees C. Developmental stage did not significantly influence the relationship between total length and Umax or Amax. Furthermore, temperature and the associated changes in water viscosity did not affect the relationship between total length and burst swimming performance. At their Umax, Reynolds numbers ranged from approximately 1,500 in the smaller tadpoles up to 50,000 for the larger animals at 24 degrees C. We suggest the positive allometry of Umax in larval L. peronii was due in part to the increases in tail width (TW) with total length (TW=-1.36L1.66), possibly reflecting the increasing importance of burst swimming performance to survival during larval development.

Animals↗
PubMedDate not supplied

Thermal acclimation effects differ between voluntary, maximum, and critical swimming velocities in two cyprinid fishes.

Temperature acclimation may be a critical component of the locomotor physiology and ecology of ectothermic animals, particularly those living in eurythermal environments. Several studies of fish report striking acclimation of biochemical and kinetic properties in isolated muscle. However, the relatively few studies of whole-animal performance report variable acclimation responses. We test the hypothesis that different types of whole-animal locomotion will respond differently to temperature acclimation, probably due to divergent physiological bases of locomotion. We studied two cyprinid fishes, tinfoil barbs (Puntius schwanenfeldii) and river barbels (Barbus barbus). Study fish were acclimated to either cold or warm temperatures for at least 6 wk and then assayed at four test temperatures for three types of swimming performance. We measured voluntary swimming velocity to estimate routine locomotor behavior, maximum fast start velocity to estimate anaerobic capacity, and critical swimming velocity to estimate primarily aerobic capacity. All three performance measures showed some acute thermal dependence, generally a positive correlation between swimming speed and test temperature. However, each performance measure responded quite differently to acclimation. Critical speeds acclimated strongly, maximum speeds not at all, and voluntary speeds uniquely in each species. Thus we conclude that long-term temperature exposure can have very different consequences for different types of locomotion, consistent with our hypothesis. The data also address previous hypotheses that predict that polyploid and eurythermal fish will have greater acclimation abilities than other fish, due to increased genetic flexibility and ecological selection, respectively. Our results conflict with these predictions. River barbels are eurythermal polyploids and tinfoil barbs stenothermal diploids, yet voluntary swimming acclimated strongly in tinfoil barbs and minimally in river barbels, and acclimation was otherwise comparable.

Acclimatization↗
PubMed2004

Constraints on adaptive evolution: the functional trade-off between reproduction and fast-start swimming performance in the Trinidadian guppy (Poecilia reticulata).

The empirical study of natural selection reveals that adaptations often involve trade-offs between competing functions. Because natural selection acts on whole organisms rather than isolated traits, adaptive evolution may be constrained by the interaction between traits that are functionally integrated. Yet, few attempts have been made to characterize how and when such constraints are manifested or whether they limit the adaptive divergence of populations. Here we examine the consequences of adaptive life-history evolution on locomotor performance in the live-bearing guppy. In response to increased predation from piscivorous fish, Trinidadian guppies evolve an increased allocation of resources toward reproduction. These populations are also under strong selection for rapid fast-start swimming performance to evade predators. Because embryo development increases a female's wet mass as she approaches parturition, an increased investment in reproductive allocation should impede fast-start performance. We find evidence for adaptive but constrained evolution of fast-start swimming performance in laboratory trials conducted on second-generation lab-reared fish. Female guppies from high-predation localities attain a faster acceleration and velocity and travel a greater distance during fast-start swimming trials. However, velocity and distance traveled decline more rapidly over the course of pregnancy in these same females, thus reducing the magnitude of divergence in swimming performance between high- and low-predation populations. This functional trade-off between reproduction and swimming performance reveals how different aspects of the phenotype are integrated and highlights the complexity of adaptation at the whole-organism level.

Adaptation, Physiological↗
PubMedDate not supplied

Laboratory-based measurements of swimming performance and related metabolic rates of field-sampled smallmouth buffalo (Ictiobus bubalus): a study of seasonal changes.

Numerous studies have demonstrated how the performance physiology of fish may change when they are acclimated to designated laboratory temperatures, but few researchers have examined naturally occurring seasonal effects on several physiological parameters associated with swimming performance. Using field-acclimatized smallmouth buffalo (Ictiobus bubalus) collected each season, we report significant seasonal effects in the following variables: critical swimming speed (modified), metabolic rate (standard, active, and scope for activity), and swimming efficiency (total and net cost of transport). Underlying seasonal changes in performance was the reproductive cycle of buffalo, particularly the period of fall gonadal recrudescence. Compared with spring, fall buffalo had a significantly lower mean critical swimming speed (72%) and lower active metabolic rate (53%), even when tested at similar temperatures. During spring, buffalo had a high mean critical swimming speed and low net cost of transport in comparison with other seasons. Buffalo are known to participate in a spring migration and spawning that may require the increased performance and efficiency observed during that season. In addition, significant sex effects were detected in winter measurements of standard metabolic rate and net cost of transport, with females the more efficient swimmers.

Animals↗