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1.
Int J Sports Med ; 41(1): 21-26, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31756737

RESUMO

The aim of the study was to verify the relative contributions of energetic and kinematic parameters to the performance in 400-m front crawl test. Fourteen middle-distance swimmers participated in the study. Oxygen consumption was measured directly and blood samples were collected to assay lactate concentration. Both oxygen consumption and lactate concentration were used to calculate the: (i) overall energy expenditure, (ii) anaerobic (alactic and lactic) and (iii) aerobic contributions. The mean centre of mass speed and intracycle velocity variation were determined through three-dimensional kinematic analysis. Mean completion time was 315.64±26.91s. Energetic contributions were as follows: 6.1±0.28% from alactic anaerobic metabolism, 5.9±0.63% from anaerobic lactic and 87.8±0.88% from aerobic. Mean intracycle velocity variation was 0.14±0.03. The results indicated that performance of 400-m test relies predominantly on aerobic power. Parameters such as lactate, mean speed, anaerobic lactic and alactic (kW) correlated with performance of 400-m test (p <0.05). Multiple linear regressions indicated that mean centre of mass speed and anaerobic alactic (kW) determined the 400-m test performance (R2=0.92). Even though the T400 is characterized by aerobic metabolism, the anaerobic alactic component cannot be negligible at this competition level.


Assuntos
Metabolismo Energético/fisiologia , Teste de Esforço/métodos , Natação/fisiologia , Fenômenos Biomecânicos/fisiologia , Comportamento Competitivo/fisiologia , Humanos , Ácido Láctico/sangue , Masculino , Oxigênio/sangue , Consumo de Oxigênio , Estudos de Tempo e Movimento , Gravação em Vídeo , Adulto Jovem
2.
Biosci Biotechnol Biochem ; 84(1): 159-170, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31483212

RESUMO

We tested whether Sake Lees (SL) had inhibitory effects on hyperalgesia in the hindpaw under psychophysical stress conditions. Male rats were subjected to repeated forced swim stress treatments (FST) from Day -3 to Day -1. Intraperiotoneal administration of SL which contained low concentration of ethanol (SLX) was conducted after each FST. On Day 0, formalin-evoked licking behaviors and Fos responses in the lumbar spinal cord (DH) and several areas within the rostral ventromedial medulla (RVM) were quantified as nociceptive responses. FST-induced hyperalgesia in the hindpaw was prevented by repeated SL and SLX treatments. Fos expression was significantly increased in DH and some areas within the RVM under FST, which was prevented by repeated SL or SLX. These findings indicated that daily administration of SL had the potential to alleviate stress-induced hyperalgesia.


Assuntos
Fermentação , Membro Posterior/metabolismo , Hiperalgesia/tratamento farmacológico , Oryza/química , Extratos Vegetais/farmacologia , Proteínas Proto-Oncogênicas c-fos/metabolismo , Corno Dorsal da Medula Espinal/metabolismo , Estresse Fisiológico/fisiologia , Animais , Comportamento Animal/efeitos dos fármacos , Etanol/química , Formaldeído/administração & dosagem , Formaldeído/farmacologia , Hiperalgesia/etiologia , Imuno-Histoquímica , Masculino , Manejo da Dor , Medição da Dor , Extratos Vegetais/administração & dosagem , Proteínas Proto-Oncogênicas c-fos/imunologia , Ratos , Ratos Sprague-Dawley , Neurônios Serotoninérgicos/efeitos dos fármacos , Neurônios Serotoninérgicos/metabolismo , Serotonina/imunologia , Serotonina/metabolismo , Natação/fisiologia , Distribuição Tecidual
3.
Zoolog Sci ; 36(6): 511-520, 2019 Dec 09.
Artigo em Inglês | MEDLINE | ID: mdl-31833322

RESUMO

To gain a better understanding of the effect of reproductive modes and swimming ability on ostracod distribution, we visited 111 randomly selected aquatic sites in Kirsehir province. A total of 35 ostracods were newly reported for the area. The number of species with and without swimming setae was not statistically different, but numbers of sexual species was significantly lower than parthenogenetics. Species without setae did not show a significant difference between sexual and parthenogenetic forms. Numbers of species with (out) setae were not significant among different elevational ranges. Distribution of parthenogenetic species was common in all 11 habitat types when sexual species were only found from three different types located from 690 to ca. 1400 m of elevational ranges. Numbers of parthenogenetic species with or without setae did not show a difference among the ranges, but sexual species without setae exhibited wider distributional ranges (690-1289 m) than species with swimming setae (690-1089 m). Species' co-occurrence revealed two positive, five negative, and 44 random pairs of co-occurrences. Wards cluster analyses portrayed three main clustering groups. While group I includes parthenogenetic and sexual species, group II covers mostly parthenogenetic species with and without setae. Group III consists of species without setae. CCA results displayed three environmental variables (water temperature, pH and elevation) effective on species distribution. Species distributed in all elevational ranges tend to show lower optimum and wider ecological tolerances. Parthenogenetic species with swimming setae and with relatively higher tolerance ranges were dominant over sexual species. The present results suggest that swimming mode has a greater effect on species distribution among the habitats than reproductive modes.


Assuntos
Crustáceos/fisiologia , Ecossistema , Natação/fisiologia , Distribuição Animal , Animais , Reprodução/fisiologia , Especificidade da Espécie , Turquia
4.
J Sports Med Phys Fitness ; 59(10): 1709-1715, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31694363

RESUMO

BACKGROUND: The purpose of this study was to investigate the effects of an Ironman-distance triathlon on bone metabolism. METHODS: Nine recreational male triathletes (39.7±8.2 years old) were voluntarily recruited before a 226-km Ironman triathlon race. Baseline blood samples were collected >1 hour before race. Serial post-race blood sampling time points included immediately (0hr), 1 hour (1hr), 1 day (d), 3 d, and 5 d after the Ironman race. RESULTS: Serum muscle damage markers, serum myoglobin, creatine kinase (CK) and lactate dehydrogenase (LDH) revealed significant post-race peak values immediately, 1hr and 1d after the race, respectively. Except for the marginally higher serum CK and myoglobin at 5d (P=0.01~0.05), all post-race serum levels of muscle damage markers were significantly higher than baseline levels (P<0.01). Serum phosphorus values were significantly higher immediately (0hr) after the Ironman race. Serum osteocalcin, an index specific to bone formation, showed a significant decrease at time points 0hr and 1hr, but a significant increase 1 day after (P<0.01) and a marginal increase 3 and 5 days after (P=0.01~0.05) the race. No difference was shown in type I collagen C-telopeptide (CTX-1), a bone resorption marker. Pearson's correlation between serum osteocalcin and CTX-1 was done at each time point, and significant correlation was shown on the 5th d after the race (r=0.591, P<0.05). CONCLUSIONS: An Ironman-distance contest induces a bone-formative-favoring turnover during the post-race period for amateur male triathletes.


Assuntos
Desempenho Atlético , Osso e Ossos/metabolismo , Adulto , Atletas , Ciclismo/fisiologia , Biomarcadores/análise , Creatina Quinase/sangue , Humanos , L-Lactato Desidrogenase/sangue , Masculino , Pessoa de Meia-Idade , Mioglobina/sangue , Resistência Física/fisiologia , Corrida/fisiologia , Natação/fisiologia
5.
PLoS Comput Biol ; 15(9): e1007354, 2019 09.
Artigo em Inglês | MEDLINE | ID: mdl-31518357

RESUMO

A variety of simple models has been proposed to understand the collective motion of animals. These models can be insightful but may lack important elements necessary to predict the motion of each individual in the collective. Adding more detail increases predictability but can make models too complex to be insightful. Here we report that deep attention networks can obtain a model of collective behavior that is simultaneously predictive and insightful thanks to an organization in modules. When using simulated trajectories, the model recovers the ground-truth interaction rule used to generate them, as well as the number of interacting neighbours. For experimental trajectories of large groups of 60-100 zebrafish, Danio rerio, the model obtains that interactions between pairs can approximately be described as repulsive, attractive or as alignment, but only when moving slowly. At high velocities, interactions correspond only to alignment or alignment mixed with repulsion at close distances. The model also shows that each zebrafish decides where to move by aggregating information from the group as a weighted average over neighbours. Weights are higher for neighbours that are close, in a collision path or moving faster in frontal and lateral locations. The network also extracts that the number of interacting individuals is dynamical and typically in the range 8-22, with 1-10 more important ones. Our results suggest that each animal decides by dynamically selecting information from the collective.


Assuntos
Comportamento Animal/fisiologia , Aprendizado Profundo , Comportamento Espacial/fisiologia , Natação/fisiologia , Peixe-Zebra/fisiologia , Animais , Biologia Computacional , Modelos Estatísticos , Comportamento Social
6.
Undersea Hyperb Med ; 46(4): 409-419, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31509897

RESUMO

The descent is a critical part of a dive, both physically and mentally. Pulmonary ventilation, expressed as respiratory minute volume (RMV) and heart rate (HR) were recorded during fast and slow descents to 35 meters (m) in open water while breathing compressed air, and during swimming horizontally at moderate velocity at an 11-m depth. Values of both types of descents were compared with reference values recorded at 11 m, the "plateau" phase, halfway through the 35-m dives. It is hypothesized that the "slow-descent" and "plateau-phase" values will be less than 'fast-descent values. Depth, cylinder pressure, water temperature and HR were recorded with a dive computer yielding time-averaged means (mRMV and mHR) for the descent and for plateau. Of the 18 divers included, 16 performed the fast descents and 11 made the slow descents. The fast descents (23 m·min-1 vertically), performed with 0-8 fin kicks, yielded mRMVDescent=28 ambient L (aL)·min-1, which is 82% higher (P⟨0.001) than mRMVPlateau of 15 aL·min-1. Further, mHRDescent was121 beats·min-1 23% higher (P⟨0.001), than mHRPlateau of 100 bpm. Slow descents (2.4 m·min-1 vertically) yielded 17 aL·min-1 with mHR=101 beats·min-1, values only slightly higher than at Plateau. The 11-m dive (swimming horizontally) yielded 24 m·min-1 with 32 fin kicks·min-1, mRMV=35 aL·min-1 and mHR=115 beats·min-1. Fast descents cause a higher RMV and HR that cannot be explained by physiology alone. Presumably mental stress is a main contributor. For dives deeper than 20 m, a descent velocity of 10 m·min-1 is recommended to reduce cardiac stress, in particular for older divers.


Assuntos
Mergulho/fisiologia , Mergulho/psicologia , Frequência Cardíaca , Ventilação Pulmonar , Estresse Psicológico/complicações , Aceleração , Adulto , Idoso , Ar Comprimido , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Valores de Referência , Respiração , Água do Mar , Estresse Fisiológico , Natação/fisiologia , Piscinas , Temperatura Ambiente
7.
PLoS Comput Biol ; 15(9): e1006883, 2019 09.
Artigo em Inglês | MEDLINE | ID: mdl-31487282

RESUMO

How muscles are used is a key to understanding the internal driving of fish swimming. However, the underlying mechanisms of some features of the muscle activation patterns and their differential appearance in different species are still obscure. In this study, we explain the muscle activation patterns by using 3D computational fluid dynamics models coupled to the motion of fish with prescribed deformation and examining the torque and power required along the fish body with two primary swimming modes. We find that the torque required by the hydrodynamic forces and body inertia exhibits a wave pattern that travels faster than the curvature wave in both anguilliform and carangiform swimmers, which can explain the traveling wave speeds of the muscle activations. Notably, intermittent negative power (i.e., power delivered by the fluid to the body) on the posterior part, along with a timely transfer of torque and energy by tendons, explains the decrease in the duration of muscle activation towards the tail. The torque contribution from the body elasticity further clarifies the wave speed increase or the reverse of the wave direction of the muscle activation on the posterior part of a carangiform swimmer. For anguilliform swimmers, the absence of the aforementioned changes in the muscle activation on the posterior part is consistent with our torque prediction and the absence of long tendons from experimental observations. These results provide novel insights into the functions of muscles and tendons as an integral part of the internal driving system, especially from an energy perspective, and they highlight the differences in the internal driving systems between the two primary swimming modes.


Assuntos
Peixes , Modelos Biológicos , Músculo Esquelético , Natação/fisiologia , Animais , Fenômenos Biomecânicos/fisiologia , Biologia Computacional , Simulação por Computador , Peixes/anatomia & histologia , Peixes/fisiologia , Músculo Esquelético/anatomia & histologia , Músculo Esquelético/fisiologia , Fenômenos Fisiológicos Musculoesqueléticos
8.
J Sports Med Phys Fitness ; 59(8): 1311-1318, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31373189

RESUMO

BACKGROUND: The purpose of this study was to examine the relationship between select physiological variables and sprint triathlon performance. METHODS: Moderately trained male triathletes (N.=15) performed two graded maximal exercise tests, on a cycle ergometer and a treadmill. Anaerobic capacity was evaluated, on a cycle ergometer and a treadmill. Within two weeks before or after the testing, all triathletes participated in a sprint triathlon race (750 m sea swim, 20 km cycle, 5 km run). RESULTS: The results showed that significant correlations exist between VO2max during cycling (r=-0.811, P<0.05) or running (r=-0.757, P<0.05) and overall triathlon performance. Stepwise multiple linear regression analysis, with triathlon performance as the dependent variable and the physiological measures during running as the independent variables, showed that VO2max (mL.min-1.kg-1), Time_CF, CHO_rate @ VT and % body fat yielded the best prediction of performance (R2=0,912). When only the physiological variables from cycling were included into the model, the results showed that VO2max (mL.min-1), VO2max (mL.min-1.kg-1) and PFmax (rpm) explained 88% of the variation in sprint triathlon performance. CONCLUSIONS: Our data indicate that overall race time for moderately trained triathletes, competing over the sprint distance can be accurately predicted from maximal laboratory tests.


Assuntos
Ciclismo/fisiologia , Corrida/fisiologia , Natação/fisiologia , Tecido Adiposo/fisiologia , Adulto , Desempenho Atlético/fisiologia , Teste de Esforço/métodos , Humanos , Modelos Lineares , Masculino , Consumo de Oxigênio/fisiologia , Fatores de Tempo
9.
Artigo em Inglês | MEDLINE | ID: mdl-31390818

RESUMO

The present research aimed to analyze the modification in performance, body composition, and autonomic modulation of reverse and traditional linear training periodization in amateur triathletes. We analyzed running and swimming performance, strength manifestation, body composition, and autonomic modulation before and after a traditional linear training periodization (four weeks of volume-based training plus four weeks of intensity-based training plus two-week tapering), a reverse linear training periodization (four weeks of intensity-based training plus four weeks of volume-based training plus two-week tapering), and a free training control physical active group (10-week free training) in 32 amateur athletes. Independently of the periodization model, the combination of two four-week mesocycles followed by a two-week taper is an efficiency strategy to avoid overreaching, obtaining an increase in parasympathetic modulation. Moreover, both types of training periodization proposed in this study do not modified body composition of amateur triathletes. Also, compared with traditional periodization, reverse periodization efficiently improves horizontal jump performance. Finally, reverse and traditional periodization were an effective strategy to improve running biomechanical, performance, and physiological variables, as well as efficient periodization strategies to improve swimming technical ability, aerobic, and anaerobic swimming performance.


Assuntos
Atletas , Sistema Nervoso Autônomo/fisiologia , Composição Corporal/fisiologia , Treino Aeróbico/métodos , Adulto , Desempenho Atlético , Ciclismo/fisiologia , Feminino , Humanos , Masculino , Corrida/fisiologia , Natação/fisiologia
10.
J Fish Biol ; 95(4): 1094-1106, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31328795

RESUMO

In this study, we investigated the effects of acoustic tag implantation on standard and routine metabolic rate (SMR and RMR, estimated via oxygen consumption), critical swimming speed (Ucrit ), survival and growth in juveniles of rainbow trout Oncorhynchus mykiss and lake trout Salvelinus namaycush. Tag burdens ranged from 1.8% to 7.5% across the two species. Growth rates in acoustic-tagged fish were equal to or higher than those in other treatments. Acoustic-tagged S. namaycush had a marginally lower Ucrit than controls but that effect was not replicated in the O. mykiss experiment. Tagging did not have clear effects on metabolic rate but there was an interaction whereby SMR and RMR tended to increase with time since surgery in tagged O. mykiss but not in other treatments (the same trend did not occur in S. namaycush). Survival was high across treatments (mean 98% survival among O. mykiss, 97.5% among S. namaycush). There were no statistically significant effects of tag burden (percentage of body mass) except for a weak negative relationship with growth rate (across species) and a weak positive relationship with Ucrit but only in the O. mykiss. Collectively, our findings suggest there were minor, context-dependent effects of acoustic tagging in juvenile S. namaycush and O. mykiss during an eight-week laboratory experiment. Further research will be required to assess whether tagging can cause meaningful behavioural effects in these species in captivity or in the wild and whether there is a tag burden threshold above which deleterious effects consistently occur.


Assuntos
Sistemas de Identificação Animal , Consumo de Oxigênio/fisiologia , Natação/fisiologia , Truta/fisiologia , Animais , Metabolismo Energético , Especificidade da Espécie , Truta/classificação
11.
Artigo em Inglês | MEDLINE | ID: mdl-31324054

RESUMO

Two endemic fish in the upper Yangtze River, the Rock Carp (Procypris rabaudi) and Prenant's Schizothoracin (Schizothorax prenanti), were used as research objects in this study to assess the effects of total dissolved gas (TDG) supersaturation on fish of varying sizes. Fish were exposed to TDG-supersaturated water at the levels of 145, 140, 135, 130, and 125%. The results showed that fish swam slowly, responded clumsily, and then exhibited spiral swimming performance after a period of exposure to TDG-supersaturated water. Fish exhibited exophthalmos, body swelling, gill bleeding, and caudal fin bleeding when they died in the TDG-supersaturated water. With the increase in TDG supersaturation, the tolerance capacity of fish to supersaturated TDG significantly reduced. At high supersaturation, the difference in survival time between species was not significant, while fish with smaller sizes showed greater tolerance capacity. At low supersaturation, the tolerance capacity of fish was mainly affected by species, and the influence of size was relatively small. With the decrease in TDG supersaturation, the catalase (CAT) activity first increased and then decreased. Rock Carp displayed significantly less activity than Prenant's Schizothoracin on exposure to TDG-supersaturated water. At high supersaturation levels, the CAT activity of Prenant's Schizothoracin of small size was greater than that of large Prenant's Schizothoracin. In contrast, small Prenant's Schizothoracin showed less CAT activity at low TDG levels than did large individuals.


Assuntos
Cyprinidae/metabolismo , Cyprinidae/fisiologia , Monitoramento Ambiental/métodos , Gases/efeitos adversos , Gases/metabolismo , Rios/química , Natação/fisiologia , Animais , China
12.
J Strength Cond Res ; 33(10): 2875-2881, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31343554

RESUMO

Muniz-Pardos, B, Gomez-Bruton, A, Matute-Llorente, A, Gonzalez-Aguero, A, Gomez-Cabello, A, Gonzalo-Skok, O, Casajus, JA, and Vicente-Rodriguez, G. Swim-specific resistance training: A systematic review. J Strength Cond Res 33(10): 2875-2881, 2019-The purpose of this systematic review was to determine which type of swim-specific training is most beneficial to enhance swimming performance and to determine which specific strength- or power-related tests better predict swimming performance. A search was conducted on PubMed, Cochrane Plus, and SPORTDiscus up to June 2018. Studies were distributed into 2 main categories: swim-specific dry land resistance training (SDLRT) and specific in-water swimming power training (SSWPT). From 1,844 citations, 25 met the inclusion criteria. It was determined that SSWPT was the most appropriate method to improve swimming performance, with tethered swimming protocols being the most studied and effective. In addition, SDLRT was a competent method to enhance swimming performance, and specifically, the inclusion of inertial training might evoke greater improvements in both strength/power capacities and swimming performance, than traditional resistance training. In conclusion, tether forces showed the greatest associations with swimming performance, although the efficacy of tethered swimming as an SSWPT method is yet to be confirmed. Further research should focus on the effects of SDLRT to verify the greater transfer of dry land resistance practices to swimming performance, with inertial training being potentially more beneficial than traditional resistance training.


Assuntos
Desempenho Atlético , Treinamento de Resistência/métodos , Natação/fisiologia , Teste de Esforço/métodos , Humanos , Água
13.
Artigo em Inglês | MEDLINE | ID: mdl-31318691

RESUMO

Background The 5HT4 receptor agonists are antidepressants with a unique mode of action. Many studies have been done on investigational drugs, and mosapride has been shown to have a 5HT3 antagonistic property. In this study, we assessed the potential anxiolytic and antidepressant effects of mosapride on Wistar albino rats. Methods The rats were randomly assigned to two models containing 4 groups of 6 animals each. In the anxiety model, four groups included 0.5 mL of 0.5% carboxymethyl cellulose (CMC), mosapride 1.5 mg/kg, mosapride 3 mg/kg and diazepam 2 mg/kg. They were dosed for 5 days. On the 3rd day, the elevated plus maze (EPM) was conducted, and on the 5th day, the open field (OF) tests were conducted. In the depression model, four groups included 0.5 mL of 0.5% CMC, mosapride 1.5 mg/kg, mosapride 3 mg/kg and imipramine 30 mg/kg. After 3 days of dosing, the forced swim test (FST) was conducted, followed by a washout period of 1 month. Then, the rats were subjected to chronic unpredictable stress with sucrose preference. Results Compared with the control, the mosapride-treated animals showed significant anxiolytic behavior at both high and low doses in the EPM and OF tests. In the FST, both high and low doses of mosapride reduced immobility. The climbing behavior was prominent at a high dose of mosapride, whereas swimming was prominent at a low dose. In the chronic stress model, both doses of mosapride preserved sucrose preference comparable to imipramine. Conclusion These findings suggest that mosapride has anxiolytic and antidepressant activities at clinically used doses.


Assuntos
Ansiolíticos/farmacologia , Antidepressivos/farmacologia , Ansiedade/tratamento farmacológico , Benzamidas/farmacologia , Depressão/tratamento farmacológico , Morfolinas/farmacologia , Animais , Comportamento Animal/efeitos dos fármacos , Modelos Animais de Doenças , Masculino , Aprendizagem em Labirinto/efeitos dos fármacos , Ratos , Ratos Wistar , Estresse Psicológico/tratamento farmacológico , Natação/fisiologia
14.
Nature ; 571(7766): 560-564, 2019 07.
Artigo em Inglês | MEDLINE | ID: mdl-31292551

RESUMO

The biophysical relationships between sensors and actuators1-5 have been fundamental to the development of complex life forms. Swimming organisms generate abundant flows that persist in aquatic environments6-13, and responding promptly to external stimuli is key to survival14-19. Here we present the discovery of 'hydrodynamic trigger waves' in cellular communities of the protist Spirostomum ambiguum that propagate-in a manner similar to a chain reaction20-22-hundreds of times faster than their swimming speed. By coiling its cytoskeleton, Spirostomum can contract its long body by 60% within milliseconds23, experiencing accelerations that can reach forces of 14g. We show that a single cellular contraction (the transmitter) generates long-ranged vortex flows at intermediate Reynolds numbers that can, in turn, trigger neighbouring cells (the receivers). To measure the sensitivity to hydrodynamic signals in these receiver cells, we present a high-throughput suction-flow device for probing mechanosensitive ion channels24 by back-calculating the microscopic forces on the cell membrane. We analyse and quantitatively model the ultra-fast hydrodynamic trigger waves in a universal framework of antenna and percolation theory25,26, and reveal a phase transition that requires a critical colony density to sustain collective communication. Our results suggest that this signalling could help to organize cohabiting communities over large distances and influence long-term behaviour through gene expression (comparable to quorum sensing16). In more immediate terms, because contractions release toxins27, synchronized discharges could facilitate the repulsion of large predators or immobilize large prey. We postulate that numerous aquatic organisms other than protists could coordinate their behaviour using variations of hydrodynamic trigger waves.


Assuntos
Comunicação Celular , Cilióforos/citologia , Cilióforos/fisiologia , Hidrodinâmica , Natação/fisiologia , Movimentos da Água , Animais , Organismos Aquáticos/citologia , Organismos Aquáticos/genética , Organismos Aquáticos/fisiologia , Biofísica , Cilióforos/genética , Citoesqueleto/fisiologia , Comportamento Predatório , Reologia , Fatores de Tempo
15.
Int J Sports Med ; 40(8): 519-527, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31288291

RESUMO

This case study reports the training of an elite 25-km open-water swimmer and the daily heart rate variability (HRV) changes during the 19-week period leading to his world champion title. Training load was collected every day and resting HRV was recorded every morning. The swimmer's characteristics were V̇O2max: 58.5 ml·min-1·kg-1, maximal heart rate: 178 beats per minute, and maximal ventilation: 170 L·min-1. Weekly training volume was 85±21 km, 39±8% was at [La]b<2 mmol · L-1 (Z1), 53±8% was at [La]b 2-4 mmol·L-1 (Z2), and 8±4% was at [La]b>4 mmol·L-1 (Z3). In the supine position, the increase in training volume and Z2 training were related to increases in rMSSD and HF. In the standing position, an increase in parasympathetic activity and decrease in sympathetic activity were observed when Z1 training increased. Seasonal changes indicated higher values in the LF/HF ratio during taper, whereas higher values in parasympathetic indices were observed in heavy workload periods. This study reports extreme load of an elite ultra-endurance swimmer. Improvements in parasympathetic indices with increasing Z2 volume indicate that this training zone was useful to improve cardiac autonomic activity, whereas Z1 training reduced sympathetic activity.


Assuntos
Frequência Cardíaca , Condicionamento Físico Humano/métodos , Resistência Física/fisiologia , Natação/fisiologia , Humanos , Ácido Láctico/sangue , Masculino , Consumo de Oxigênio , Sistema Nervoso Parassimpático/fisiologia , Taxa Respiratória , Posição Ortostática , Decúbito Dorsal , Sistema Nervoso Simpático/fisiologia , Adulto Jovem
16.
J Fish Biol ; 95(3): 893-902, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31265133

RESUMO

In this study, swim-tunnel respirometry was performed on Atlantic salmon Salmo salar post-smolts in a 90 l respirometer on individuals and compared with groups or individuals of similar sizes tested in a 1905 l respirometer, to determine if differences between set-ups and protocols exist. Standard metabolic rate (SMR) derived from the lowest oxygen uptake rate cycles over a 20 h period was statistically similar to SMR derived from back extrapolating to zero swim speed. However, maximum metabolic rate (MMR) estimates varied significantly between swimming at maximum speed, following an exhaustive chase protocol and during confinement stress. Most notably, the mean (±SE) MMR was 511 ± 15 mg O2 kg-1 h-1 in the swim test which was 52% higher compared with 337 ± 9 mg O2 kg-1 in the chase protocol, showing that the latter approach causes a substantial underestimation. Performing group respirometry in the larger swim tunnel provided statistically similar estimates of SMR and MMR as for individual fish tested in the smaller tunnel. While we hypothesised a larger swim section and swimming in groups would improve swimming performance, Ucrit was statistically similar between both set-ups and statistically similar between swimming alone v. swimming in groups in the larger set-up, suggesting that this species does not benefit hydrodynamically from swimming in a school in these conditions. Different methods and set-ups have their own respective limitations and advantages depending on the questions being addressed, the time available, the number of replicates required and if supplementary samplings such as blood or gill tissues are needed. Hence, method choice should be carefully considered when planning experiments and when comparing previous studies.


Assuntos
Metabolismo Energético/fisiologia , Consumo de Oxigênio/fisiologia , Salmo salar/fisiologia , Natação/fisiologia , Animais
17.
Chemosphere ; 235: 126-135, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31255752

RESUMO

As the exposure of organisms to contaminants can provoke harmful effects, some organisms try to avoid a continuous exposure by using different strategies. The aim of the current study was to assess the ability of the shrimp Palaemon varians to detect a triclosan gradient and escape to less contaminated areas. Two multi-compartmented exposure systems (the linear system and the HeMHAS-Heterogeneous Multi-Habitat Assay System) were used and then results were compared. Finally, it was aimed how sensitive the avoidance response is by comparing it with other endpoints through a sensitivity profile by biological groups and the species sensitive distribution. The distribution of the shrimps along the triclosan gradient was dependent on the concentrations, not exceeding 3% for 54 µg/L in the linear system and 7% for 81 µg/L in the HeMHAS; 25% of organisms preferred the compartment with the lowest concentrations in both systems. Half of the population seems to avoid concentrations around 40-50 µg/L. The triclosan concentration that might start (threshold) to trigger an important avoidance (around 20%) was estimated to be of 18 µg/L. The profile of sensitivity to triclosan showed that avoidance by shrimps was less sensitive than microalgae growth and avoidance by guppy; however, it might occur even at concentrations considered safe for more than 95% of the species. In summary, (i) the HeMHAS proved to be a suitable system to simulate heterogeneous contamination scenarios, (ii) triclosan triggered the avoidance response in P. varians, and (iii) the avoidance was very sensitive compared to other ecotoxicological responses.


Assuntos
Aprendizagem da Esquiva/fisiologia , Reação de Fuga/efeitos dos fármacos , Palaemonidae/fisiologia , Triclosan/toxicidade , Poluentes Químicos da Água/análise , Animais , Ecossistema , Ecotoxicologia , Microalgas/fisiologia , Poecilia/fisiologia , Alimentos Marinhos , Natação/fisiologia , Poluentes Químicos da Água/toxicidade
18.
J Strength Cond Res ; 33(8): 2185-2193, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31344014

RESUMO

Lomax, M, Kapus, J, Brown, PI, and Faghy, M. Impact of weekly swimming training distance on the ergogenicity of inspiratory muscle training in well-trained youth swimmers. J Strength Cond Res 33(8): 2185-2193, 2019-The aim of this study was to examine the impact of weekly swimming training distance on the ergogenicity of inspiratory muscle training (IMT). Thirty-three youth swimmers were recruited and separated into a LOW and HIGH group based on weekly training distance (≤31 km·wk and >41 km·wk, respectively). The LOW and HIGH groups were further subdivided into control and IMT groups for a 6-week IMT intervention giving a total of 4 groups: LOWcon, LOWIMT, HIGHcon, and HIGHIMT. Before and after the intervention period, swimmers completed maximal effort 100- and 200-m front crawl swims, with maximal inspiratory and expiratory mouth pressures (PImax and PEmax, respectively) assessed before and after each swim. Inspiratory muscle training increased PImax (but not PEmax) by 36% in LOWIMT and HIGHIMT groups (p ≤ 0.05), but 100- and 200-m swims were faster only in the LOWIMT group (3 and 7% respectively, p ≤ 0.05). Performance benefits only occurred in those training up to 31 km·wk and indicate that the ergogenicity of IMT is affected by weekly training distance. Consequently, training distances are important considerations, among others, when deciding whether or not to supplement swimming training with IMT.


Assuntos
Treino Aeróbico/métodos , Músculos Respiratórios/fisiologia , Natação/fisiologia , Adolescente , Desempenho Atlético/fisiologia , Feminino , Humanos , Masculino , Testes de Função Respiratória
19.
J Sports Sci ; 37(20): 2287-2299, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31190612

RESUMO

Athletes' energy distribution over a race (e.g. pacing behaviour) varies across different sports. Swimming is a head-to-head sport with unique characteristics, such as propulsion through water, a multitude of swimming stroke types and lane-based racing. The aim of this paper was to review the existing literature on pacing behaviour in swimming. According to PRISMA guidelines, 279 articles were extracted using the PubMed and Web of Science databases. After the exclusion process was conducted, 16 studies remained. The findings of these studies indicate that pacing behaviour is influenced by the race distance and stroke type. Pacing behaviours in swimming and time-trial sports share numerous common characteristics. This commonality can most likely be attributed to the lane-based racing set-up. The low efficiency of swimming resulting from propulsion through the water induces a rapid accumulation of blood lactate, prompting a change in swimmers' biomechanical characteristics, with the goal of minimising changes in velocity throughout the race. Although the literature on youth swimmers is scarce, youth swimmers demonstrate more variable pacing profiles and have more difficulty in selecting the most beneficial energy distribution.


Assuntos
Comportamento Competitivo/fisiologia , Natação/fisiologia , Natação/psicologia , Fatores Etários , Fenômenos Biomecânicos , Metabolismo Energético , Humanos , Ácido Láctico/sangue , Destreza Motora/fisiologia
20.
Acta Cir Bras ; 34(5): e201900503, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31166462

RESUMO

PURPOSE: To analyze the muscle changes with high-intensity aerobic training (HIAT) in an animal model of renal disease (RD). METHODS: Twenty one adult Wistar rats were divided into 3 groups: healthy sedentary (HS), RD sedentary (RDS), RD aerobic training (RDAT). RDS and RDAT were subjected to unilateral renal ischemia-reperfusion (10 min) and 21days after that, RDAT was subjected to 6 weeks HIAT (swimming). Serum creatinine (Cr) and muscle morphometry (cross-sectional area = CSA) of gastrocnemius were analyzed. RESULTS: Cr was higher (p = 0.0053) in RDS (0.82 ± 0.04) than in the others (RDAT 0.55 ± 0.04; HS 0.55 ± 0.04). Morphometric analysis (class interval of CSA in µm2/absolute frequency of muscle fibers in each class) indicated that 50th percentile occurred in: HS 7th class (3000.00-3499.00/515), RDS, 8th class (3500.00-3999.00/484), RDAT 5th class (2000.00-2499.00/856). CSA of largest fibers in RDS, RDAT, HS was 9953.00 µm2, 9969.00 µm2,11228.00 µm2, respectively. High frequency of fibers with lower CSA occurred in 4th, 5th, 6th and 7th class in RDA, absence of fibers into 22nd, 23rd classes (RDS and RDAT). CONCLUSION: HIAT in an animal model of RD resulted in increased the number of muscle fibers with smaller CSA.


Assuntos
Músculo Esquelético/fisiopatologia , Condicionamento Físico Animal/fisiologia , Insuficiência Renal/fisiopatologia , Animais , Peso Corporal/fisiologia , Creatinina/sangue , Modelos Animais de Doenças , Rim/irrigação sanguínea , Rim/fisiopatologia , Fibras Musculares Esqueléticas/fisiologia , Ratos Wistar , Valores de Referência , Traumatismo por Reperfusão/fisiopatologia , Reprodutibilidade dos Testes , Comportamento Sedentário , Natação/fisiologia
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