Body Swimming Research Articles

Prevalence, intensity of infection and risk factors of urinary schistosomiasis in pre-school and school aged children in Guma Local Government Area, Nigeria

ObjectiveTo determine the prevalence and intensity of infection and the risk factors associated with urinary schistosomiasis in pre-school and school aged children in Guma Local Government Area of Benue State, Nigeria. MethodsUrine filtration technique using polycarbonate membrane filters was employed to process urine specimens and to determine presence of Schistosoma haematobium eggs in urine. Questionnaires were also administered to children to collect information on socio-demographic data and water-contact activities. ResultsAn overall prevalence of 55.0% (165/300) was recorded out of the 300 urine samples examined. Prevalence of infection varied between 36.0%-64.0% with a significant difference (χ2= 11.59, P=0.041) between the different communities visited. Males were more infected (60.6%, 103/170) than females (47.7%, 62/130) with a significant difference (χ2= 4.95, P=0.026). The age-related prevalence showed higher prevalence (70.5%, 36/52) in the 11-15 year old children than that in the 1-5 year old ones (44.9%, 53/118). A significant difference was observed in the prevalence between the age groups (χ2=10.56, P=0.014). The prevalence of light intensity of infection (1-49 eggs/10 mL of urine) (86.6%) was significantly higher than that of heavy intensity of infection (≥50 eggs/10 mL of urine) (13.3%) in the area (t=16.48, P=0.000). Water contact activities of the children revealed that children that were involved in irrigation and those that went swimming in water bodies were observed to be at higher risk of becoming infected with urinary schistosomiasis in the area with odd ratios (risk factors) of 2.756 (1.334-5.693) and 2.366 (1.131-4.948) respectively at P<0.05 level. ConclusionsThe study revealed the hyperendemicity of urinary schistosomiasis in the pre-school and school aged children in Guma Local Government Area. It is therefore recommended that praziquantel should be administered to children in the area and systematic epidemiological studies should be undertaken in the whole Local Government Area and the State at large to discover new foci of infection.

Hydrodynamics and energetics of jumping copepod nauplii and copepodids.

Within its life cycle, a copepod goes through drastic changes in size, shape and swimming mode. In particular, there is a stark difference between the early (nauplius) and later (copepodid) stages. Copepods inhabit an intermediate Reynolds number regime (between ~1 and 100) where both viscosity and inertia are potentially important, and the Reynolds number changes by an order of magnitude during growth. Thus we expect the life stage related changes experienced by a copepod to result in hydrodynamic and energetic differences, ultimately affecting the fitness. To quantify these differences, we measured the swimming kinematics and fluid flow around jumping Acartia tonsa at different stages of its life cycle, using particle image velocimetry and particle tracking velocimetry. We found that the flow structures around nauplii and copepodids are topologically different, with one and two vortex rings, respectively. Our measurements suggest that copepodids cover a larger distance compared to their body size in each jump and are also hydrodynamically quieter, as the flow disturbance they create attenuates faster with distance. Also, copepodids are energetically more efficient than nauplii, presumably due to the change in hydrodynamic regime accompanied with a well-adapted body form and swimming stroke.

Mexican blind cavefish use mouth suction to detect obstacles

Fish commonly use their lateral line system to detect moving bodies such as prey and predators. A remarkable case is the Mexican blind cavefish Astyanax fasciatus, which evolved the ability to detect non-moving obstacles. The swimming body of A. fasciatus generates fluid disturbances, the alteration of which by an obstacle can be sensed by the fish's lateral line system. It is generally accepted that these alterations can provide information on the distance to the obstacle. We observed that A. fasciatus swimming in an unfamiliar environment open and close their mouths at high frequency (0.7-4.5 Hz) in order to generate suction flows. We hypothesized that repeated mouth suction generates a hydrodynamic velocity field, which is altered by an obstacle, inducing pressure gradients in the neuromasts of the lateral line and corresponding strong lateral line stimuli. We observed that the frequency and rate of mouth-opening events varied with the fish's distance to obstacles, a hallmark of pulse-based navigation mechanisms such as echolocation. We formulated a mathematical model of this hitherto unrecognized mechanism of obstacle detection and parameterized it experimentally. This model suggests that suction flows induce lateral line stimuli that are weakly dependent on the fish's speed, and may be an order of magnitude stronger than the correspondent stimuli induced by the fish's gliding body. We illustrate that A. fasciatus can navigate non-visually using a combination of two deeply ancestral and highly conserved mechanisms of ray-finned fishes: the mechanism of sensing water motion by the lateral line system and the mechanism of generating water motion by mouth suction.

Red muscle proportions and enzyme activities in deep‐sea demersal fishes

Owing to the paucity of data on the red muscle of deep-sea fishes, the goal of this study was to determine the proportions of red muscle in demersal fishes and its enzymatic activities to characterize how routine swimming abilities change with depths of occurrence. Cross sectional analysis of the trunk musculature was used to evaluate the proportion of red muscle in 38 species of Californian demersal fishes living at depths between 100 and 3000 m. The activity of metabolic enzymes was also assayed in a sub-set of 18 species. Benthic fishes had lower proportions of red muscle and lower metabolic enzyme activities than benthopelagic species. Mean proportion of red muscle declined significantly with depth with the greatest range of values in shallow waters and species with low proportions found at all depths. This suggested that while sedentary species occur at all depths, the most active species occur in shallow waters. Citrate synthase activity declined significantly with depth across all species, indicating that the mass-specific metabolic capacity of red muscle is lower in deep-sea species. These patterns may be explained by coupling of red and white muscle physiologies, a decrease in physical energy of the environment with depth or by the prevalence of anguilliform body forms and swimming modes in deep-living species.

Defensive Responses of Cuttlefish to Different Teleost Predators

We evaluated cuttlefish (Sepia officinalis) responses to three teleost predators: bluefish (Pomatomus saltatrix), summer flounder (Paralichthys dentatus), and black seabass (Centropristis striata). We hypothesized that the distinct body shapes, swimming behaviors, and predation tactics exhibited by the three fishes would elicit markedly different antipredator responses by cuttlefish. Over the course of 25 predator-prey behavioral trials, 3 primary and 15 secondary defense behaviors of cuttlefish were shown to predators. In contrast, secondary defenses were not shown during control trials in which predators were absent. With seabass-a benthic, sit-and-pursue predator-cuttlefish used flight and spent more time swimming in the water column than with other predators. With bluefish-an active, pelagic searching predator-cuttlefish remained closely associated with the substrate and relied more on cryptic behaviors. Startle (deimatic) displays were the most frequent secondary defense shown to seabass and bluefish, particularly the Dark eye ring and Deimatic spot displays. We were unable to evaluate secondary defenses by cuttlefish to flounder-a lie-and-wait predator-because flounder did not pursue cuttlefish or make attacks. Nonetheless, cuttlefish used primary defense during flounder trials, alternating between cryptic still and moving behaviors. Overall, our results suggest that cuttlefish may vary their behavior in the presence of different teleost predators: cryptic behaviors may be more important in the presence of active searching predators (e.g., bluefish), while conspicuous movements such as swimming in the water column and startle displays may be more prevalent with relatively sedentary, bottom-associated predators (e.g., seabass).

Effect of Swim Cap Model on Passive Drag

Hydrodynamics plays an important role in swimming because even small decreases in a swimmer's drag can lead to performance improvements. During the gliding phases of a race, the head of a swimmer is an important point of impact with the fluid, and the swim cap, even if it covers only a small portion of the swimmer's body, can have an influence on drag. The purpose of this study was to investigate the effects on passive drag (Dp) of wearing 3 different types of swim caps (LSC: a lycra cap; CSC: a silicone cap; HSC: a silicone helmet cap without seams). Sixteen swimmers were tested at 3 velocities (1.5, 1.7, 1.9 m·s), and the Dp measurements were repeated at each condition 5 times. A statistical analysis revealed significant differences in drag (p < 0.01) among caps: Dp is 5-6.5% lower for HSC than for CSC at all speeds and 6% lower in HSC than CSC at 1.9 m·s. No differences in Dp were observed between LSC and CSC at all speeds. Thus, the differences in Dp are based on the type of material (lycra vs. silicone) and on the presence/lack of seams: the HSC swim cap is the most rigid, the most adherent to the swimmer's head, and does not allow the formation of wrinkles compared with the other 2 investigated swim caps. Therefore, the following conclusions can be made: (a) swimmers should take care when selecting their swim cap if they want to improve the fluid dynamics at the "leading edge" of their body and (b) because Dp is affected by the swim cap model, care should be taken when comparing data from different studies, especially at faster investigated speeds.

Winning looks: body image among adolescent female competitive swimmers

The purpose of this qualitative study was to explore and describe the circumstances related to body image among adolescent female swimmers. Thirteen in-depth interviews were conducted with 11–13 year-old swimmers who trained at USA Swimming clubs. Using grounded theory methodology, a theoretical model consisting of a core category embedded in four themes emerged. Creating Myself included key components of self-presentation, perception and attitude encircled in four contextual themes: The Backdrop (previous thoughts, feelings and experiences), Responses from Others (comments from peers, family and important others), The Swimmer Body (the swim suit, physical traits, mental qualities and beliefs about swimmers’ physiques) and Being and Getting Comfortable (self-observation, current thoughts, feelings and self-management strategies). Implications of the model for research and professional practise were discussed.

Swimming of a model ciliate near an air-liquid interface

In this work, the role of the hydrodynamic forces on a swimming microorganism near an air-liquid interface is studied. The lubrication theory is utilized to analyze hydrodynamic effects within the narrow gap between a flat interface and a small swimmer. By using an archetypal low-Reynolds-number swimming model called "squirmer," we find that the magnitude of the vertical swimming velocity is on the order of O(εlnε), where ε is the ratio of the gap width to the swimmer's body size. The reduced swimming velocity near an interface can explain experimental observations of the aggregation of microorganisms near a liquid interface.

CFD ANALYSIS OF THE BODY POSITION DURING THE GLIDING IN SWIMMING

BackgroundThe swimmer's body position after immersion determines the success of the start rather than his/her starting body position in the block or during the fly.1 There are swimmers gliding in...

Metabolism and chemical composition of marine pelagic amphipods: synthesis toward a global bathymetric model

Respiration and ammonia excretion data and chemical composition data [water content, ash, carbon (C), nitrogen (N) and C:N ratios] of 18–32 amphipods (hyperiids and gammarids) from the epipelagic through bathypelagic zones of the world’s oceans were compiled. The independent variables including body mass, habitat temperature and mid-sampling depth were all significant predictors of respiration, accounting for 65–83 % of the variance in the data, while the former two variables were significant predictors of ammonia excretion, accounting for 64–77 % of the variance. Atomic O:N ratios (respiration:ammonia excretion) ranged from 11 to 74 (median 21.5). C composition was negatively correlated with habitat temperature, but water contents, ash, N, and the C:N ratio were uncorrelated with the three independent variables. As judged by C:N ratios, protein was considered to be the major organic component of most pelagic amphipods. However, some amphipods from >500 m depth exhibited high C:N ratios (>10) suggesting a large deposition of lipids in the body. Comparison of the present results with global bathymetric models of euphausiids and pelagic copepods revealed that respiration rates of the pelagic amphipods were near-equal to the rates of euphausiids but greater than the rates of pelagic copepods, reflecting taxon-specific body morphology and swimming behavior among the three taxa. As a marked feature of body chemical composition, the pelagic amphipods exhibited extremely high ash content (mean 25 % of DM) due to their possession of a robust exoskeleton.

‘If I go in like a Cranky Sea Lion, I Come out like a Smiling Dolphin’: Marathon Swimming and the Unexpected Pleasures of Being a Body in Water

Drawing on (auto)ethnographic research—on the process of becoming a marathon swimmer, this paper argues that conventional characterisations of marathon swimming as being ‘80 per cent mental and 20 per cent physical’ reprise a mind–body split that at worst excludes women and at best holds them to a masculine standard. This in turn draws the focus towards sensory deprivation, bodily suffering and overcoming, to the exclusion of the pleasures of swimming, beyond the expected ones such as the challenge of swim completion. By exploring instead the ‘shifted sensorium’ of marathon swimming, and examples of the autotelic pleasures of swimming, this paper argues that training changes the way swimming body feels, and that it is these changes that enable a swimmer to feel ‘at home’ in an environment to which it does not naturally belong. This focus on the sensory aspects of swimming, and its unexpected pleasures, both highlights the ways in which those pleasures do not flow unproblematically to women, and brings to light alternative and politically provocative ways of experiencing the gendered sporting body. This highlights the contingency, however constrained, of even the most entrenched ways of thinking about bodies, both within and outside sport.

Swim club membership and the reproduction of happy, healthy children

Through ethnographic methods, I examine the ways in which upper middle-class families facilitate the reproduction of their healthy lifestyles through their affiliation with the Valley View Swim and Tennis Club, a semi-private facility located near a major mid-Atlantic city in the USA. Drawing on Sociologist Pierre Bourdieu’s understanding of social class, I argue that club membership operates as future investment in children’s health with the cultivation of their healthy swimming bodies serving as visible markers of class-based, embodied capital. Specifically, the pool offers parents a distinctive cultural context in which to augment children’s medical health and physical safety, build a foundation for lifelong physical activity practices, help them achieve an ideal body weight and control their consumption habits. Ultimately, the club serves as a powerful and influential physical space in which families engage in important health-related practices and processes contributing to the reproduction of their healthy, upper middle-class children.

208 3D-CGに基づく競泳用水着を着用したスイマーの筋骨格解析(筋骨格モデルの応用)

The objective of this study was to develop the method of musculoskeletal simulation for a swimmer attaching a competitive swimwear. For the simulation, the body geometry and joint motion were put into the swimming human simulation model SWUM in order to calculate the distributed fluid forces acting on the whole swimmer's body. The distributed fluid forces were put into the musculoskeletal model. In addition to the fluid forces, the forces induced by the tension of the swimwear were also considered. The distribution of the forces acting on the swimmer was calculated from the stress distribution of the swimwear. Since the swimwear targeted in the present study was a half spat type, the forces by the swimwear acted on three segments; the right and left thighs, and the pelvis. Therefore, the ratio of one distributed force to these three segments had to be determined. In order to determine this ratio, the deformation of the swimwear measured in an experiment was used. As an example, the simulation for the crawl stroke was conducted. The results showed the time-varying effect of the swimwear on the muscle activity during swimming.

3D-CG Based Musculoskeletal Simulation for a Swimmer Wearing Competitive Swimwear

The objective of this study was to develop a musculoskeletal simulation for a swimmer wearing competitive swimwear. For the simulation, the body geometry and joint motion were put into the swimming human simulation model SWUM in order to calculate the distributed fluid forces acting on the whole swimmer's body. The distributed fluid forces were put into the musculoskeletal model. In addition to the fluid forces, the forces induced by the tension of the swimwear were also considered. As an example, the simulation for the crawl stroke was conducted. The results showed the time-varying effect of the swimwear on the muscle activity during swimming.

Micromotions of a Swimmer in the 3-D Incompressible Fluid Governed by the Nonstationary Stokes Equation

In this paper we consider a model describing the self-propelled motion of a small abstract swimmer in the three-dimensional (3-D) incompressible fluid, governed by the nonstationary Stokes equation. Typically this fluid is associated with the low Reynolds numbers when inertia is viewed as negligible. It is assumed that the swimmer's body consists of finitely many subsequently connected parts, identified with the fluid they occupy, linked to each other by rotational and elastic Hooke's forces [A. Y. Khapalov and G. Trinh, Discrete Contin. Dyn. Syst. Ser. A, 33 (2012), pp. 1513--1544], [A. Y. Khapalov, Int. J. Appl. Math. Comput. Sci., 23 (2013), pp. 277--290]. Our goal is to derive a formula for asymptotically small motions of this swimmer in the 3-D incompressible fluid. These results can be useful for biological and engineering applications dealing with the study and design of propulsion systems in fluids to serve as a constructive approach to studying their steering (or controllability) properties [A. Y...

Geometric aspects of transformations of forces acting upon a swimmer in a 3-D incompressible fluid

Our goal in this paper is to investigate how the geometricshape of a swimmer affects the forces acting upon it in a 3-$D$ incompressible fluid, such as governed by the non-stationary Stokes or Navier-Stokes equations.Namely, we are interested in the following question: How will the swimmer's internal forces (i.e., not moving the center of swimmer's mass when it is not inside a fluid) ``transform'' their actions when the swimmer is placed into a fluid (thus, possibly, creating its self-propelling motion)?We focus on the case when the swimmer's body consists of either small parallelepipedsor balls. Such problems are of interest in biology and engineeringapplication dealing with propulsion systems in fluids.

Propulsive performance of a body with a traveling-wave surface

A body with a traveling-wave surface (TWS) is investigated by solving the incompressible Navier-Stokes equation numerically to understand the mechanisms of a novel propulsive strategy. In this study, a virtual model of a foil with a flexible surface which performs a traveling-wave movement is used as a free swimming body. Based on the simulations by varying the traveling-wave Reynolds number and the amplitude and wave number of the TWS, some propulsive properties including the forward speed, the swimming efficiency, and the flow field are analyzed in detail. It is found that the mean forward velocity increases with the traveling-wave Reynolds number, the amplitude, and the wave number of the TWS. A weak wake behind the free swimming body is identified and the propulsive mechanisms are discussed. Moreover, the TWS is a "quiet" propulsive approach, which is an advantage when preying. The results obtained in this study provide a novel propulsion concept, which may also lead to an important design capability for underwater vehicles.

Influence of a postural change of the swimmer's head in hydrodynamic performances using 3D CFD

This study deals with recent researches undertaken by the authors in the field of hydrodynamics of human swimming. The aim of this numerical study was to investigate the flow around the entire swimmer's body. The results presented in this article focus on the combination of a 3D computational fluid dynamics code and the use of the k–ω turbulence model, in the range of Reynolds numbers representative of a swimming level varying from national to international competition. Emphasis is placed on the influence of a postural change of the swimmer's head in hydrodynamic performances, which is directly related to the reduction of overall drag. These results confirm and complete those, less accurate, of a preliminary 2D study recently published by the authors and allow the authors to optimise the swimmer's head position in underwater swimming.

Analysis on the Time and Frequency Domains of the Acceleration in Front Crawl Stroke

The swimming involves accelerations and decelerations in the swimmer’s body. Thus, the main objective of this study is to make a temporal and frequency analysis of the acceleration in front crawl swimming, regarding the gender and the performance. The sample was composed by 31 male swimmers (15 of high-level and 16 of low-level) and 20 female swimmers (11 of high-level and 9 of low-level). The acceleration was registered from the third complete cycle during eight seconds in a 25 meters maximum velocity test. A position transducer (200Hz) was used to collect the data, and it was synchronized to an aquatic camera (25Hz). The acceleration in the temporal (root mean square, minimum and maximum of the acceleration) and frequency (power peak, power peak frequency and spectral area) domains was calculated with Fourier analysis, as well as the velocity and the spectrums distribution in function to present one or more main peaks (type 1 and type 2). A one-way ANOVA was used to establish differences between gender and performance. Results show differences between genders in all the temporal domain variables (p<0.05) and only the Spectral Area (SA) in the frequency domain (p<0.05). Between gender and performance, only the Root Mean Square (RMS) showed differences in the performance of the male swimmers (p<0.05) and in the higher level swimmers, the Maximum (Max) and the Power Peak (PP) of the acceleration showed differences between both genders (p<0.05). These results confirms the importance of knowing the RMS to determine the efficiency of the swimmers regarding gender and performance level

3차원 테크놀러지를 이용한 여성용 수영복의 가슴부위 외관 및 패턴 기능성 향상에 관한 연구

Considerable number of women are enjoying swimming, however, the chest-region of swimsuits including cup inserts are not stable during swimming. The purpose of this study was to explore alternate designs and methods of stabilizing the breast cup to the swimmer's body by using 3D technology to design and position the pad and cup pattern of the swimming suit. To position the pad optimally, a 3D pattern of a nude woman was divided into blocks and different reduction rates were applied to blocks around the outlines of the breast. Two types of 3D patterns were developed. The first, referred to as the 'basic 3D pattern' provided for the curved surface of the breast point to be maintained with the remaining slack distributed evenly along the neckline, armhole and side seam. The second, referred to as the '1/3 shoulder moved 3D pattern' ignored the curved nature of the breast point by overlapping, with the resulting position of the shoulder strip moved toward the center. Three women of corresponding size and body shape evaluated the two 3D pattern designs as well as the conventional 2D pattern style of swimsuit. Respondents rated the'the basic 3D pattern' design highest in terms of stability and easy of movement in the chest region.