RESUMEN

For 88 years, biologists and engineers have sought to understand the hydrodynamics enabling dolphins to swim at speeds seemingly beyond their energetic capabilities, a phenomenon known as Gray's paradox. Hydromechanical models calculating the drag of swimming dolphins estimated power requirements for sustained high-speed swimming, which were physiologically impossible. Using an uncrewed aerial vehicle, we calculated the total power of free-ranging dusky dolphins (Lagenorhynchus obscurus) at speeds from 0.9 to 6.9 m s-1, deriving drag coefficients (Cd) and drag. Our results showed that the Cd decreased exponentially with speed, reducing drag by up to 89% at speeds >2 m s-1, with an additional 17% reduction during porpoising (>4.0 m s-1). At 6.9 m s-1, drag was 32 N, with a power of 15.8 W kg-1, nearly identical to the mass-specific allometric prediction for the maximum aerobic capacity of other mammals and physiologically possible. The Cd at speeds >2.5 m s-1 indicated reduced turbulence in the boundary layer around the dolphin's body, thereby reducing drag. The ability of dusky dolphins to swim at sustained high speeds resulted from an exponential decrease in Cd, which was further reduced by porpoising, thereby explaining the low drag and locomotory power that resolved Gray's paradox.

Asunto(s)

Delfines , Modelos Biológicos , Natación , Animales , Delfines/fisiología , Natación/fisiología , Fenómenos Biomecánicos , Hidrodinámica

RESUMEN

OBJECTIVE: Glucagon-like peptide-1 (GLP1) and leptin (Lep) are afferent signals that regulate energy metabolism. Lactational hypernutrition results in hyperphagia and adiposity in adult life, and these events can be prevented by exercise. We evaluated the effects of swimming training on hypothalamic (GLP1-R) and Lep receptor (Lep-R) gene expressions in lactational hypernutrition-induced obesity. METHODS: On the 3rd postnatal day, the litter sizes of lactating dams were adjusted to small litters (SL; 3 pups/dams) or normal litters (NL; 9 pups/dams). After weaning (21 days), NL and SL male rats were randomly distributed to sedentary (Sed) and exercised (Exe) groups. Exercised mice swam (30 min/3 times/week) for 68 days. Food intake and body weight gain were registered. At 92 days, intraperitoneal glucose and insulin tolerance tests were performed and rats were euthanized at 93 days; adipose tissue depots were weighed, and blood counts and plasma biochemical analyses performed. Hypothalamus were isolated to evaluate Lep-R and GLP1-R gene expressions. RESULTS: Small litters sedentary rats presented increased body weight gain, adiposity, insulin sensibility and higher fasting values of glucose and triglycerides, besides higher hypothalamic gene expressions of Lep-R and GLP1-R, compared to NLSed animals. SLExe rats did not develop obesity or metabolic abnormalities and Lep-R and GLP1-R hypothalamic gene expressions were normalized. CONCLUSION: Lactational hypernutrition induces obesity and metabolic dysfunction in adult life, in association with higher hypothalamic expressions of the Lep-R and GLP1-R genes. Exercise prevented obesity and improved metabolic state in SL overnourished rats, and normalized their hypothalamic Lep-R and GLP1-R gene expressions.

Asunto(s)

Hipotálamo , Obesidad , Condicionamiento Físico Animal , Ratas Wistar , Receptores de Leptina , Natación , Animales , Hipotálamo/metabolismo , Obesidad/metabolismo , Obesidad/genética , Obesidad/prevención & control , Condicionamiento Físico Animal/fisiología , Condicionamiento Físico Animal/métodos , Masculino , Receptores de Leptina/genética , Receptores de Leptina/metabolismo , Femenino , Natación/fisiología , Tamaño de la Camada , Receptor del Péptido 1 Similar al Glucagón/metabolismo , Receptor del Péptido 1 Similar al Glucagón/genética , Ratas , Lactancia/metabolismo , Lactancia/fisiología , Péptido 1 Similar al Glucagón/metabolismo , Leptina/sangre , Leptina/metabolismo , Distribución Aleatoria , Expresión Génica , Ingestión de Alimentos/fisiología , Adiposidad/fisiología

RESUMEN

The majority of participants in Ironman triathlon races are age group athletes. We have extensive knowledge about recreational athletes' training and competition participation. Nonetheless, Ironman age group triathletes must achieve fast race times to qualify for the Ironman World Championship in Hawaii. They can, therefore, benefit from knowing where the fastest Ironman racecourses in the world are. The aim of the present study was to investigate where the fastest Ironman racecourses for age group triathletes are located in the world. Data from 677,702 Ironman age group finishers' records (544,963 from men and 132,739 from women) originating from 228 countries and participating in 444 events across 66 different Ironman race locations between 2002 and 2022 were analyzed. Data was analyzed through traditional descriptive statistics and with machine learning regression models. Four algorithms were tested (Random Forest Regressor, XG Boost Regressor, Cat Boot Regressor, and Decision Tree Regressor). The models used gender, age group, country of origin, environmental factors (average air and water temperatures), and the event location as independent variables to predict the final overall race time. Despite the majority of successful Ironman age group triathletes originating from the USA (274,553), followed by athletes from the United Kingdom (55,410) and Canada (38,264), these countries exhibited average overall race times that were significantly slower compared to the fastest countries. Most of the triathletes competed in Ironman Wisconsin (38,545), followed by Ironman Florida (38,157) and Ironman Lake Placid (34,341). The fastest overall race times were achieved in Ironman Copenhagen (11.68 ± 1.38 h), followed by Ironman Hawaii (11.72 ± 1.86 h), Ironman Barcelona (11.78 ± 1.43 h), Ironman Florianópolis (11.80 ± 1.52 h), Ironman Frankfurt (12.03 ± 1.38 h) and Ironman Kalmar (12.08 ± 1.47 h). The fastest athletes originated from Belgium (11.48 ± 1.47 h), followed by athletes from Denmark (11.59 ± 1.40 h), Switzerland (11.62 ± 1.49 h), Austria (11.68 ± 1.50), Finland (11.68 ± 1.40 h) and Germany (11.74 ± 15.1 h). Flat running and cycling courses were associated with faster overall race times. Three of the predictive models identified the 'country' and 'age group' variables as the most important predictors. Environmental characteristics showed the lowest influence regarding the other variables. The origin of the athlete was the most predictive variable whereas environmental characteristics showed the lowest influence. Flat cycling and flat running courses were associated with faster overall race times. The fastest overall race times were achieved mainly in European races such as Ironman Copenhagen, Ironman Hawaii, Ironman Barcelona, Ironman Florianópolis, Ironman Frankfurt and Ironman Kalmar. The fastest triathletes originated from European countries such as Belgium, Denmark, Switzerland, Austria, Finland, and Germany.

Asunto(s)

Atletas , Rendimiento Atlético , Humanos , Masculino , Femenino , Europa (Continente) , Adulto , Rendimiento Atlético/fisiología , Persona de Mediana Edad , Ciclismo/estadística & datos numéricos , Carrera/fisiología , Natación/fisiología , Factores de Edad

RESUMEN

Orientation in the ocean can be challenging because of a lack of landmarks. Evidence is accumulating that jellyfish, once considered to be passive drifters, can also show directional swimming to avoid stranding ashore, using ocean waves for orientation, just like hatchling turtles.

Asunto(s)

Escifozoos , Natación , Animales , Escifozoos/fisiología , Natación/fisiología , Navegación Espacial/fisiología

RESUMEN

The present study aimed to explore the effect of swimming exercise on vascular calcification in type 2 diabetic rats and its related molecular mechanism. Male Sprague Dawley (SD) rats were randomly divided into normal control (NC), diabetes control (DC) and diabetes+exercise (DE) groups. The DC and DE groups were intraperitoneally injected with streptozotocin (STZ) and fed with high-fat diet to establish type 2 diabetes mellitus model. The NC and DC groups did not exercise, and the DE group performed swimming exercise for 8 weeks. ELISA was used to detect the serum glycated hemoglobin A1c (HbA1c) level. The aortas of rats were taken as sample. Assay kits were used to detect vascular calcium content and alkaline phosphatase (ALP) activity. Von Kossa staining was used to detect calcium deposition. qRT-PCR was used detect the expression of microRNA-145 (miR-145). Western blot was used to detect the protein expression levels of smooth muscle contraction markers, calcification marker and related proteins. The results showed that, compared with the NC group, the blood glucose, serum HbA1c level, vascular calcium content and ALP activity in the DC group were significantly increased, the protein expression levels of smooth muscle contraction markers smooth muscle protein 22α (SM22α) and α-smooth muscle actin (α-SMA) were significantly down-regulated, and the protein expression level of calcification marker osteopontin (OPN) was significantly up-regulated; Compared with the DC group, the serum HbA1c level, vascular calcium content and ALP activity in the DE group were significantly decreased, the protein expression levels of SM22α and α-SMA were significantly up-regulated, and the protein expression level of OPN was significantly down-regulated; Compared with the NC group, the expression of miR-145-5p in the DC group was significantly down-regulated, and the protein expression levels of transforming growth factor-ß (TGF-ß), SMAD2, ERK1/2 and p-ERK1/2 were significantly up-regulated; Compared with the DC group, the expression of miR-145-5p was significantly up-regulated in the DE group, while the expressions of TGF-ß, ERK1/2 and p-ERK1/2 were significantly down-regulated. These results suggest that miR-145/TGF-ß signaling is involved in the improving effects of 8-week swimming exercise on glucose metabolism disorder, vascular smooth muscle cell phenotype switching and vascular calcification in type 2 diabetes mellitus.

Asunto(s)

Diabetes Mellitus Experimental , Diabetes Mellitus Tipo 2 , MicroARNs , Condicionamiento Físico Animal , Ratas Sprague-Dawley , Natación , Calcificación Vascular , Animales , Masculino , Ratas , MicroARNs/metabolismo , MicroARNs/genética , Calcificación Vascular/metabolismo , Calcificación Vascular/etiología , Diabetes Mellitus Tipo 2/metabolismo , Diabetes Mellitus Experimental/metabolismo , Natación/fisiología , Factor de Crecimiento Transformador beta/metabolismo

RESUMEN

Autonomous ocean-exploring vehicles have begun to take advantage of onboard sensor measurements of water properties such as salinity and temperature to locate oceanic features in real time. Such targeted sampling strategies enable more rapid study of ocean environments by actively steering towards areas of high scientific value. Inspired by the ability of aquatic animals to navigate via flow sensing, this work investigates hydrodynamic cues for accomplishing targeted sampling using a palm-sized robotic swimmer. As proof-of-concept analogy for tracking hydrothermal vent plumes in the ocean, the robot is tasked with locating the center of turbulent jet flows in a 13,000-liter water tank using data from onboard pressure sensors. To learn a navigation strategy, we first implemented RL on a simulated version of the robot navigating in proximity to turbulent jets. After training, the RL algorithm discovered an effective strategy for locating the jets by following transverse velocity gradients sensed by pressure sensors located on opposite sides of the robot. When implemented on the physical robot, this gradient following strategy enabled the robot to successfully locate the turbulent plumes at more than twice the rate of random searching. Additionally, we found that navigation performance improved as the distance between the pressure sensors increased, which can inform the design of distributed flow sensors in ocean robots. Our results demonstrate the effectiveness and limits of flow-based navigation for autonomously locating hydrodynamic features of interest.

Asunto(s)

Biomimética , Peces , Hidrodinámica , Océanos y Mares , Robótica , Natación , Robótica/instrumentación , Animales , Peces/fisiología , Biomimética/métodos , Biomimética/instrumentación , Natación/fisiología , Movimientos del Agua , Algoritmos , Diseño de Equipo , Simulación por Computador

RESUMEN

Respiratory plasticity is a beneficial response to chronic hypoxia in fish. Red drum, a teleost that commonly experiences hypoxia in the Gulf of Mexico, have shown respiratory plasticity following sublethal hypoxia exposure as juveniles, but implications of hypoxia exposure during development are unknown. We exposed red drum embryos to hypoxia (40% air saturation) or normoxia (100% air saturation) for 3 days post fertilization (dpf). This time frame encompasses hatch and exogenous feeding. At 3 dpf, there was no difference in survival or changes in size. After the 3-day hypoxia exposure, all larvae were moved and reared in common normoxic conditions. Fish were reared for ∼3 months and effects of the developmental hypoxia exposure on swim performance and whole-animal aerobic metabolism were measured. We used a cross design wherein fish from normoxia (N=24) were exercised in swim tunnels in both hypoxia (40%, n=12) and normoxia (100%, n=12) conditions, and likewise for hypoxia-exposed fish (n=10 in each group). Oxygen consumption, critical swim speed (Ucrit), critical oxygen threshold (Pcrit) and mitochondrial respiration were measured. Hypoxia-exposed fish had higher aerobic scope, maximum metabolic rate, and higher liver mitochondrial efficiency relative to control fish in normoxia. Interestingly, hypoxia-exposed fish showed increased hypoxia sensitivity (higher Pcrit) and recruited burst swimming at lower swim speeds relative to control fish. These data provide evidence that early hypoxia exposure leads to a complex response in later life.

Asunto(s)

Hipoxia , Consumo de Oxígeno , Natación , Animales , Natación/fisiología , Hipoxia/fisiopatología , Larva/crecimiento & desarrollo , Larva/fisiología

RESUMEN

The ridges of the dermal denticles of migratory sharks have inspired riblets to reduce the frictional drag of a fluid. In particular, the dermal denticles of white sharks (Carcharodon carcharias) are characterized by a high middle ridge and low side ridges. The detailed morphology of their denticles and their variation along the body, however, have never been investigated. Moreover, the hydrodynamic function of high-low combinations of ridges is unknown. In this article, the ridge spacings and heights of the white shark denticles were three-dimensionally quantified using microfocus X-ray computed tomography. Then, the swimming speed at which the ridges would reduce drag was hydrodynamically calculated with a flat plate body model and previous riblet data. High ridges with a large spacing were found to effectively reduce drag at a migration speed of 2.3 m s-1, while adjacent high and low ridges with a small spacing reduced drag at a burst hunting speed of 5.1 m s-1. Moreover, the above hydrodynamic calculation method was also applied to the shortfin mako shark and an extinct giant shark (called megalodon) with known ridge spacings, resulting in the estimated hunting speeds of 10.5 m s-1and 5.9 m s-1, respectively.

Asunto(s)

Tiburones , Natación , Animales , Tiburones/anatomía & histología , Tiburones/fisiología , Natación/fisiología , Hidrodinámica , Modelos Biológicos

RESUMEN

This study evaluated the effect of fish total length (LT) and three water temperatures (10, 15 and 20 °C) on the critical swimming speed (Ucrit) of the species Percilia irwini (2.9-6.3 cm LT), Cheirodon galusdae (3.4-5.5 cm LT), and Trichomycterus areolatus (4.0-6.3 cm LT). An Ucrit estimation model was constructed for each species as a function of temperature and size. The results showed mean Ucrit for P. irwini of 44.56, 53.83 and 63.2 cm s-1 at 10, 15 and 20 °C, respectively: 55.34, 61.74 and 70.05 cm s-1 for C. galusdae and 56.18, 63.01 and 71.09 cm s-1 for T. areolatus. Critical velocity depended on the interaction between species, body length and water. The swimming performance increased significantly with rising temperature in all three species. The velocity also increased with greater fish total length. After controlling for fish total length, velocity also increased with higher temperature in the three species. This research is relevant to small fish species that require conservation measures.

Asunto(s)

Peces , Agua Dulce , Natación , Temperatura , Animales , Natación/fisiología , Peces/fisiología , Tamaño Corporal

RESUMEN

Since assessing aerobic capacity is key to enhancing swimming performance, a simple and widely applicable technology should be developed. Therefore, we aimed to noninvasively visualize real-time changes in sweat lactate (sLA) levels during swimming and investigate the relationship between lactate thresholds in sweat (sLT) and blood (bLT). This prospective study included 24 university swimmers (age: 20.7 s ± 1.8 years, 58% male) who underwent exercise tests at incremental speeds with or without breaks in a swimming flume to measure heart rate (HR), bLT, and sLT based on sLA levels using a waterproof wearable lactate sensor attached to the dorsal upper arm on two different days. The correlation coefficient and Bland-Altman methods were used to verify the similarities of the sLT with bLT and personal performance. In all tests, dynamic changes in sLA levels were continuously measured and projected onto the wearable device without delay, artifacts, or contamination. Following an initial minimal current response, with increasing speed the sLA levels increased substantially, coinciding with a continuous rise in HR. The speed at sLT strongly correlated with that at bLT (p < 0.01 and r = 0.824). The Bland-Altman plot showed a strong agreement (mean difference: 0.08 ± 0.1 m/s). This prospective study achieved real-time sLA monitoring during swimming, even with vigorous movement. The sLT closely approximated bLT; both were subsequently validated for their relevance to performance.

Asunto(s)

Frecuencia Cardíaca , Ácido Láctico , Sudor , Natación , Humanos , Natación/fisiología , Estudios Prospectivos , Masculino , Ácido Láctico/análisis , Femenino , Adulto Joven , Sudor/química , Frecuencia Cardíaca/fisiología , Dispositivos Electrónicos Vestibles , Prueba de Esfuerzo , Umbral Anaerobio/fisiología

RESUMEN

Micro-sensors, such as pressure and flow sensors, are usually adopted to attain actual fluid information around swimming biomimetic robotic fish for hydrodynamic analysis and control. However, most of the reported micro-sensors are mounted discretely on body surfaces of robotic fish and it is impossible to analyzed the hydrodynamics between the caudal fin and the fluid. In this work, a biomimetic caudal fin integrated with a resistive pressure sensor is designed and fabricated by laser machined conductive carbon fibre composites. To analyze the pressure exerted on the caudal fin during underwater oscillation, the pressure on the caudal fin is measured under different oscillating frequencies and angles. Then a model developed from Bernoulli equation indicates that the maximum pressure difference is linear to the quadratic power of the oscillating frequency and the maximum oscillating angle. The fluid disturbance generated by caudal fin oscillating increases with an increase of oscillating frequency, resulting in the decrease of the efficiency of converting the kinetic energy of the caudal fin oscillation into the pressure difference on both sides of the caudal fin. However, perhaps due to the longer stability time of the disturbed fluid, this conversion efficiency increases with the increase of the maximum oscillating angle. Additionally, the pressure variation of the caudal fin oscillating with continuous different oscillating angles is also demonstrated to be detected effectively. It is suggested that the caudal fin integrated with the pressure sensor could be used for sensing thein situflow field in real time and analyzing the hydrodynamics of biomimetic robotic fish.

Asunto(s)

Aletas de Animales , Biomimética , Diseño de Equipo , Peces , Robótica , Natación , Animales , Robótica/instrumentación , Aletas de Animales/fisiología , Biomimética/instrumentación , Biomimética/métodos , Peces/fisiología , Natación/fisiología , Hidrodinámica , Análisis de Falla de Equipo , Transductores de Presión , Presión , Materiales Biomiméticos , Transductores

RESUMEN

Red drum, Sciaenops ocellatus, are a marine teleost native to the Gulf of Mexico that routinely experiences periods of low oxygen (hypoxia). Recent work has demonstrated this species has the capacity to improve aerobic performance in hypoxia through respiratory acclimation. However, it remains unknown how hypoxia acclimation impacts anaerobic metabolism in red drum, and the consequences of exhaustive exercise and recovery. Juvenile fish were acclimated to normoxia (n = 15, DO 90.4 ± 6.42 %) or hypoxia (n = 15, DO 33.6 ± 7.2 %) for 8 days then sampled at three time points: at rest, after exercise, and after a 3 h recovery period. The resting time point was used to characterize the acclimated phenotype, while the remaining time points demonstrate how this phenotype responds to exhaustive exercise. Whole blood, red muscle, white muscle, and heart tissues were sampled for metabolites and enzyme activity. The resting phenotype was characterized by lower pHe and changes to skeletal muscle ATP. Exhaustive exercise increased muscle lactate, and decreased phosphocreatine and ATP with no effect of acclimation. Interestingly, hypoxia-acclimated fish had higher pHe and pHi than control in all exercise time points. Red muscle ATP was lower in hypoxia-acclimated fish versus control at each sample period. Moreover, acclimated fish increased lactate dehydrogenase activity in the red muscle. Hypoxia acclimation increased white muscle ATP and hexokinase activity, a glycolytic enzyme. In a gait-transition swim test, hypoxia-acclimated fish recruited anaerobic-powered burst swimming at lower speeds in normoxia compared to control fish. These data suggest that acclimation increases reliance on anaerobic metabolism, and does not benefit recovery from exhaustive exercise.

Asunto(s)

Aclimatación , Hipoxia , Músculo Esquelético , Natación , Animales , Natación/fisiología , Músculo Esquelético/metabolismo , Anaerobiosis , Hipoxia/metabolismo , Aclimatación/fisiología , Peces/fisiología , Peces/metabolismo , Perciformes/fisiología , Perciformes/metabolismo , Adenosina Trifosfato/metabolismo , Ácido Láctico/metabolismo , Ácido Láctico/sangre

RESUMEN

Having a profound influence on marine and coastal environments worldwide, jellyfish hold significant scientific, economic, and public interest.1,2,3,4,5 The predictability of outbreaks and dispersion of jellyfish is limited by a fundamental gap in our understanding of their movement. Although there is evidence that jellyfish may actively affect their position,6,7,8,9,10 the role of active swimming in controlling jellyfish movement, and the characteristics of jellyfish swimming behavior, are not well understood. Consequently, jellyfish are often regarded as passively drifting or randomly moving organisms, both conceptually2,11 and in process studies.12,13,14 Here we show that the movement of jellyfish is modulated by distinctly directional swimming patterns that are oriented away from the coast and against the direction of surface gravity waves. Taking a Lagrangian viewpoint from drone videos that allows the tracking of multiple adjacent jellyfish, and focusing on the scyphozoan jellyfish Rhopilema nomadica as a model organism, we show that the behavior of individual jellyfish translates into a synchronized directional swimming of the aggregation as a whole. Numerical simulations show that this counter-wave swimming behavior results in biased correlated random-walk movement patterns that reduce the risk of stranding, thus providing jellyfish with an adaptive advantage critical to their survival. Our results emphasize the importance of active swimming in regulating jellyfish movement and open the way for a more accurate representation in model studies, thus improving the predictability of jellyfish outbreaks and their dispersion and contributing to our ability to mitigate their possible impact on coastal infrastructure and populations.

Asunto(s)

Escifozoos , Natación , Animales , Natación/fisiología , Escifozoos/fisiología

RESUMEN

BACKGROUND: Brown adipose tissue (BAT) is a thermogenic tissue that uncouples oxidative phosphorylation from ATP synthesis and increases energy expenditure via non-shivering thermogenesis in mammals. Cold exposure and exercise have been shown to increase BAT and browning of white adipose tissue (WAT) in mice. This study aimed to determine whether there is an additive effect of exercise during cold exposure on markers related to browning of adipose tissue. in Wistar rats. METHODS: Twenty-four male Wistar rats were randomly divided into three groups: Control (C, 25˚C), Swimming in Neutral (SN, 30˚C) water, and Swimming in Cold (SC, 15˚C) water. Swimming included intervals of 2-3 min, 1 min rest, until exhausted, three days a week for six weeks, with a training load of 3-6% body weight. After the experimental protocol, interscapular BAT and inguinal subcutaneous white adipose tissue (WAT) were excised, weighed, and processed for beiging marker gene expression. RESULTS: SN and SC resulted in lower body weight gain, associated with reduced WAT and BAT volume and increased BAT number with greater effects observed in SC. Myostatin protein expression was lower in BAT, WAT, soleus muscle, and serum NC and SC compared to the C group. Expression of the interferon regulatory factor-4 (IRF4) gene in both BAT and WAT tissues was significantly greater in the SC than in the C. Expression of the PGC-1α in BAT was significantly increased in the SC compared to C and increased in WAT in NC and SC. Expression of the UCP1 in BAT and WAT increased in the SC group compared to other groups. CONCLUSION: The findings demonstrate that six weeks of swimming training in cold water promotes additive effects of the expression of genes and proteins involved in the browning process of adipose tissue in Wistar rats. Myostatin inhibition may possess a regulator effect on the PGC-1α - UCP1 pathway that mediates adipose tissue browning.

Asunto(s)

Tejido Adiposo Pardo , Tejido Adiposo Blanco , Frío , Miostatina , Condicionamiento Físico Animal , Ratas Wistar , Natación , Termogénesis , Animales , Masculino , Ratas , Tejido Adiposo Pardo/metabolismo , Tejido Adiposo Blanco/metabolismo , Peso Corporal , Metabolismo Energético , Miostatina/metabolismo , Miostatina/genética , Coactivador 1-alfa del Receptor Activado por Proliferadores de Peroxisomas gamma/metabolismo , Coactivador 1-alfa del Receptor Activado por Proliferadores de Peroxisomas gamma/genética , Transducción de Señal , Natación/fisiología , Termogénesis/fisiología , Agua/metabolismo

RESUMEN

Schooling fish rely on a social network created through signaling between its members to interact with their environment. Previous studies have established that vision is necessary for schooling and that flow sensing by the lateral line system may aid in a school's cohesion. However, it remains unclear to what extent flow provides a channel of communication between schooling fish. Based on kinematic measurements of the speed and heading of schooling tetras (Petitella rhodostoma), we found that compromising the lateral line by chemical treatment reduced the mutual information between individuals by ∼13%. This relatively small reduction in pairwise communication propagated through schools of varying size to reduce the degree and connectivity of the social network by more than half. Treated schools additionally showed more than twice the spatial heterogeneity of fish with unaltered flow sensing. These effects were much more substantial than the changes that we measured in the nearest-neighbor distance, speed and intermittency of individual fish by compromising flow sensing. Therefore, flow serves as a valuable supplement to visual communication in a manner that is revealed through a school's network properties.

Asunto(s)

Comunicación Animal , Movimientos del Agua , Animales , Sistema de la Línea Lateral/fisiología , Fenómenos Biomecánicos , Conducta Social , Natación/fisiología

RESUMEN

BACKGROUND: High-level expertise in team-sports is associated with superior performance on executive functions (EFs) such as working memory (WM) and action inhibition, and with altered activation of brain areas related to these EFs. In most such studies, athletes were sampled from the domain of dynamic (i.e., open-skill) team-sports (e.g., soccer players). Whether static (i.e., closed-skill) team-sports athletes (e.g., rowers and synchronized swimmers) also show superior EFs performance and differential EF-related functional brain activation remains unknown. METHODS: We recruited 14 elite closed-skill athletes, all national champions, and internationally competitive in various rowing disciplines, as well as 14 controls matched on gender, age, and education, and had them perform working memory and action inhibition (stop-signal) tasks during fMRI scanning. RESULTS: Group differences in performance in either task failed to obtain statistical significance, although athletes showed a numerical trend toward higher WM capacity than controls. Importantly, task-related BOLD responses suggested that Olympic closed-skill team athletes show stronger recruitment of brain areas that emphasize relatively stable task demands and weaker engagement of brain areas that emphasize rapidly changing demands imposed by extraneous stimulation. CONCLUSION: Functional brain imaging data suggest elite closed-skill athletes may employ different cognitive strategies.

Asunto(s)

Atletas , Encéfalo , Inhibición Psicológica , Imagen por Resonancia Magnética , Memoria a Corto Plazo , Humanos , Memoria a Corto Plazo/fisiología , Masculino , Encéfalo/fisiología , Encéfalo/diagnóstico por imagen , Femenino , Adulto Joven , Atletas/psicología , Adulto , Natación/fisiología , Deportes Acuáticos/fisiología , Pruebas Neuropsicológicas , Mapeo Encefálico , Función Ejecutiva/fisiología , Oxígeno/sangre

RESUMEN

BACKGROUND: Cold water swimming is growing in popularity, especially among women. We have previously reported that women felt that cold water swimming helps with their menstrual and menopause symptoms. But little is known about the habits of women who cold water swim. OBJECTIVES: To determine the habits of women who cold water swim. DESIGN: This was a mixed-methods study. METHODS: An online survey asked women who cold water swim about their experience of swimming and how this affected their menstrual and menopause symptoms. The survey was advertised for 2 months on social media, with a focus on advertising in cold water swimming Facebook groups. In this article, only the questions on the women's swimming habits were analyzed. RESULTS: The analysis of 1114 women, mainly from the United Kingdom, revealed that most had been swimming for 1-5 years (79.5%). Most swim in the sea (64.4%), and only 15.5% swim alone. The majority (89.0%) swim all year around, swimming for mainly 30-60 min in the summer and 5-15 min in the winter. The women mostly swim wearing swimming costumes (skins) throughout the year. The majority of the free-text responses showed women found mental and physical benefits from cold water swimming. CONCLUSION: It was not surprising to learn that women swim for longer in the summer than the winter, but hearing how they feel cold water swimming helps their physical and mental health is important. With the limitations on access and safety of many wild swimming sites in the United Kingdom, it is time to ensure that cold water swimming is safer and more supported.

Asunto(s)

Frío , Natación , Humanos , Femenino , Natación/fisiología , Adulto , Persona de Mediana Edad , Encuestas y Cuestionarios , Reino Unido , Menopausia/fisiología , Hábitos , Adulto Joven , Menstruación/fisiología

RESUMEN

The sturgeon is an important commercial aquaculture species in China. The measurement of sturgeon mass plays a remarkable role in aquaculture management. Furthermore, the measurement of sturgeon mass serves as a key phenotype, offering crucial information for enhancing growth traits through genetic improvement. Until now, the measurement of sturgeon mass is usually conducted by manual sampling, which is work intensive and time consuming for farmers and invasive and stressful for the fish. Therefore, a noninvasive volume reconstruction model for estimating the mass of swimming sturgeon based on RGB-D sensor was proposed in this paper. The volume of individual sturgeon was reconstructed by integrating the thickness of the upper surface of the sturgeon, where the difference in depth between the surface and the bottom was used as the thickness measurement. To verify feasibility, three experimental groups were conducted, achieving prediction accuracies of 0.897, 0.861, and 0.883, which indicated that the method can obtain the reliable, accurate mass of the sturgeon. The strategy requires no special hardware or intensive calculation, and it provides a key to uncovering noncontact, high-throughput, and highly sensitive mass evaluation of sturgeon while holding potential for evaluating the mass of other cultured fishes.

Asunto(s)

Acuicultura , Peces , Natación , Animales , Peces/fisiología , Natación/fisiología , Acuicultura/métodos

RESUMEN

BACKGROUND: This study aimed to conduct a detailed and comparative analysis of body composition and dietary habits in elite swimming and water polo athletes. Through the examination of these key parameters, this study seeks to compare the dietary intake of these two distinct aquatic sports disciplines. METHODS: A total of 10 top-level swimmers and 13 water polo athletes participated in anthropometric and body composition assessments, as well as a detailed analysis of nutritional intake. To compare the two groups, an independent samples t-test was used, and variance homogeneity was checked using Levene's test. The effect size of the group differences was evaluated using Hedges' g. RESULTS: Water polo athletes showed significantly greater height (189.4 ± 2.9 vs. 186.5 ± 2.0 cm, p = 0.013), body mass index (24.3 ± 1.4 vs. 22.1 ± 0.5 kg/m2, p < 0.001), fat-free mass (62.9 ± 1.4 vs. 61.1 ± 1.38 kg, p < 0.001), skeletal muscle mass (47.1 ± 1.3 vs. 43.9 ± 1.6 kg, p < 0.001), and overall weight (86.9 ± 6.9 vs. 76.7 ± 2.2 kg, p < 0.001) in comparison to swimmers. Swimmers consumed greater amounts of mean daily energy (60.0 ± 1.0 vs. 39.0 ± 1.0 kcal/kg, p < 0.001), carbohydrate (7.8 ± 0.3 vs. 4.4 ± 0.5 g/kg, p < 0.001), protein (1.7 ± 0.5 vs. 1.4 ± 0.5 g/kg, p < 0.001), and fat (2.4 ± 0.5 vs. 1.7 ± 0.5 g/kg, p < 0.001) compared to water polo athletes. CONCLUSION: Our findings highlight the need for differentiated targeted nutritional interventions to enhance athletic performance in different types of water sports. Compared to water polo athletes, swimmers consumed significantly higher amounts of calories, matching their increased calorie demand from their specific training regime. However, this is an observational study and the differential needs of energy and macronutrients in water sports should be confirmed by studies with energy expenditure measurements.

Asunto(s)

Atletas , Composición Corporal , Natación , Deportes Acuáticos , Humanos , Natación/fisiología , Atletas/estadística & datos numéricos , Masculino , Irán , Adulto Joven , Deportes Acuáticos/fisiología , Femenino , Dieta/estadística & datos numéricos , Ingestión de Energía , Adolescente , Conducta Alimentaria/fisiología , Índice de Masa Corporal , Adulto

RESUMEN

This study aimed to examine the ability of adolescents to maintain breathing rhythm while swimming with and without goggles, in the context of pedagogical interventions for implementation of water competence skills, rather than simply teaching swimming technique (strokes). 25 females and 25 males, 12-13 years old, swam the front crawl both with goggles and without goggles. Distance covered and the ability to maintain breathing rhythm were evaluated by experts. For both girls and boys, the lack of goggles reduced the breath control. The boys in contrast to the girls, could "swim" (cover a distance) but did not have the "competence" to swim effectively/safely-with breathing rhythm-regardless of the goggle factor. Goggle-free swimming as an autonomous component of water competence is highly recommended in elementary swimming education. The following elements for pedagogical intervention in the area of water competence development are proposed: (1) the formatting of breath control on the basis of the student's preferred, simplest form of swimming (not strokes); (2) the a priori treatment of swimming goggles as an unnecessary teaching aid; (3) the gender differences in area of both adaptation in visual perception (the goggles factor) and motor control (breath control factor) should be considered.

Asunto(s)

Natación , Humanos , Natación/fisiología , Masculino , Femenino , Adolescente , Niño , Respiración