Swimming performance is considered a key trait determining the ability of fish to survive. Hydrodynamic theory predicts that the energetic costs required for fishes to swim should vary with speed ...according to a U-shaped curve, with an expected energetic minimum at intermediate cruising speeds and increasing expenditure at low and high speeds. However, to date no complete datasets have shown an energetic minimum for swimming fish at intermediate speeds rather than low speeds. To address this knowledge gap, we used a negatively buoyant fish, the clearnose skate Raja eglanteria, and took two approaches: a classic critical swimming speed protocol and a single-speed exercise and recovery procedure. We found an anaerobic component at each velocity tested. The two approaches showed U-shaped, though significantly different, speed–metabolic relationships. These results suggest that (i) postural costs, especially at low speeds, may result in J- or U-shaped metabolism–speed curves; (ii) anaerobic metabolism is involved at all swimming speeds in the clearnose skate; and (iii) critical swimming protocols might misrepresent the true costs of locomotion across speeds, at least in negatively buoyant fish.
Flagellated bacteria such as Escherichia coli and Bacillus subtilis exhibit effective mechanisms for swimming in fluids and exploring the surrounding environment. In isotropic fluids such as water, ...the bacteria change swimming direction through the run-and-tumble process. Lyotropic chromonic liquid crystals (LCLCs) have been introduced recently as an anisotropic environment in which the direction of preferred orientation, the director, guides the bacterial trajectories. In this work, we describe the behavior of bacteria B. subtilis in a homeotropic LCLC geometry, in which the director is perpendicular to the bounding plates of a shallow cell. We demonstrate that the bacteria are capable of overcoming the stabilizing elastic forces of the LCLC and swim perpendicularly to the imposed director (and parallel to the bounding plates). The effect is explained by a finite surface anchoring of the director at the bacterial body; the role of surface anchoring is analyzed by numerical simulations of a rod realigning in an otherwise uniform director field. Shear flows produced by a swimming bacterium cause director distortions around its body, as evidenced both by experiments and numerical simulations. These distortions contribute to a repulsive force that keeps the swimming bacterium at a distance of a few micrometers away from the bounding plates. The homeotropic alignment of the director imposes two different scenarios of bacterial tumbling: one with an 180° reversal of the horizontal velocity and the other with the realignment of the bacterium by two consecutive 90° turns. In the second case, the angle between the bacterial body and the imposed director changes from 90° to 0° and then back to 90°; the new direction of swimming does not correlate with the previous swimming direction.
The question of how individuals in a population organize when living in groups arises for systems as different as a swarm of microorganisms or a flock of seagulls. The different patterns for moving ...collectively involve a wide spectrum of reasons, such as evading predators or optimizing food prospection. Also, the schooling pattern has often been associated with an advantage in terms of energy consumption. In this study, we use a popular aquarium fish, the red nose tetra fish, Hemigrammus bleheri, which is known to swim in highly cohesive groups, to analyze the schooling dynamics. In our experiments, fish swim in a shallow-water tunnel with controlled velocity, and stereoscopic video recordings are used to track the 3D positions of each individual in a school, as well as their tail-beating kinematics. Challenging the widespread idea of fish favoring a diamond pattern to swim more efficiently Weihs D (1973) Nature 241:290–291, we observe that when fish are forced to swim fast—well above their free-swimming typical velocity, and hence in a situation where efficient swimming would be favored—the most frequent configuration is the “phalanx” or “soldier” formation, with all individuals swimming side by side. We explain this observation by considering the advantages of tail-beating synchronization between neighbors, which we have also characterized. Most importantly, we show that schooling is advantageous as compared with swimming alone from an energy-efficiency perspective.
수영 리터러시의 개념 정립 및 구성요인 탐색 이은미; Lee Eunmi; 김승환 ...
한국체육학회지,
01/2024, Letnik:
63, Številka:
1
Journal Article
본 연구는 수영교육에 대한 새로운 관점의 철학적이고 개념적인 분석과 논리전개가 필요한 상황임을 고려하여, 이를 위한 선행과제로서 수영 리터러시의 개념을 정립하고 수영 리터러시의 구성요인을 도출하고자 하였다. 이와 같은 목적을 달성하기 위해 대학교수, 현장연구자, 수영 지도자, 수영선수 등으로 이루어진 자문위원 16명을 대상으로 수영 리터러시의 개념과 ...구성요인에 대해 7회의 델파이조사를 진행하였다. 이에 따른 주요결과는 다음과 같다. 첫째, 수영 리터러시의 개념은 수중 및 수상에서 스스로 자유롭게 이동할 수 있고, 자신과 타인을 구하는 활동을 이해하며, 때론 경쟁을 통해 기록 및 동작에 도전하고 성취하는 총체적 신체활동 및 교육활동이자 삶을 향유하는 능력으로 정의되었다. 둘째, 수영 리터러시의 구성요인에서 수영은 생존수영, 생활체육수영, 엘리트수영으로 분류되었다. 셋째, 각 분류별 주요집단은 학생과 지도자, 참여자와 지도자, 선수와 지도자로 분류되었다. 넷째, 분류별 구성요인은 각 집단별 3개씩 18개와 공통요인 3개인 총 21개가 도출되었다. 본 연구결과는 다양한 형태의 수영 교육 현장에서 각각의 목적과 내용에 대한 체계 확립 및 교육 방향 정립에 도움을 줄 것이며 학교체육과 생활체육, 그리고 엘리트체육의 발전에도 기여할 것이다. 또한 이는 중앙부처 및 지자체, 유관기관, 학교 등에서 정책적이고 실질적인 시사점을 줄 것으로 기대된다.
The purpose of this study is to considers the need for a philosophical and conceptual analysis with a new perspective on swimming education. As a preliminary task for this purpose, we aimed to establish the concept of swimming literacy and derive the components. To achieve this goal, we conducted seven rounds of Delphi surveys with a panel of 16 advisory members, including university professors, field researchers, swimming instructors, and swimmers, to explore the concept and components of swimming literacy. The key findings are as follows. First, the concept of swimming literacy is defined as the holistic ability to move freely in and on the water, understand activities involving self-rescue and the rescue of others, occasionally challenge oneself through competition in records and movements, and enjoy life through comprehensive physical and educational activities. Second, within the components of swimming literacy, swimming was classified into survival swimming, recreational sports swimming, and elite swimming. Third, the primary groups for each classification were categorized as students and instructors, participants and instructors, and athletes and instructors. Fourth, a total of 21 factors were derived, with 18 factors specific to each group (three factors for each subgroup) and three common factors. The findings of this study are expected to contribute to the systematic establishment of various forms of swimming education in different contexts, aligning with their respective purposes and contents. Additionally, it is anticipated that these results will contribute to the development of school sports, recreational sports, and elite sports. Furthermore, it is expected that the study will provide policy and practical implications for central government agencies, local authorities, relevant institutions, and schools.
Competitive swimming has a long history and is currently one of the largest Olympic sports, with 16 pool events. Several aspects separate swimming from most other sports such as (i) the prone ...position; (ii) simultaneous use of arms and legs for propulsion; (iii) water immersion (i.e. hydrostatic pressure on thorax and controlled respiration); (iv) propulsive forces that are applied against a fluctuant element; and (v) minimal influence of equipment on performance. Competitive swimmers are suggested to have specific anthropometrical features compared with other athletes, but are nevertheless dependent on physiological adaptations to enhance their performance. Swimmers thus engage in large volumes of training in the pool and on dry land. Strength training of various forms is widely used, and the energetic systems are addressed by aerobic and anaerobic swimming training. The aim of the current review was to report results from controlled exercise training trials within competitive swimming. From a structured literature search we found 17 controlled intervention studies that covered strength or resistance training, assisted sprint swimming, arms-only training, leg-kick training, respiratory muscle training, training the energy delivery systems and combined interventions across the aforementioned categories. Nine of the included studies were randomized controlled trials. Among the included studies we found indications that heavy strength training on dry land (one to five repetitions maximum with pull-downs for three sets with maximal effort in the concentric phase) or sprint swimming with resistance towards propulsion (maximal pushing with the arms against fixed points or pulling a perforated bowl) may be efficient for enhanced performance, and may also possibly have positive effects on stroke mechanics. The largest effect size (ES) on swimming performance was found in 50 m freestyle after a dry-land strength training regimen of maximum six repetitions across three sets in relevant muscle-groups (ES 1.05), and after a regimen of resisted- and assisted-sprint training with elastic surgical tubes (ES 1.21). Secondly, several studies suggest that high training volumes do not pose any immediate advantage over lower volumes (with higher intensity) for swim performance. Overall, very few studies were eligible for the current review although the search strategy was broad and fairly liberal. The included studies predominantly involved freestyle swimming and, overall, there seems to be more questions than answers within intervention-based competitive swimming research. We believe that this review may encourage other researchers to pursue the interesting topics within the physiology of competitive swimming.
mcwatson100@gmail.com There are around 236 000 drowning deaths worldwide each year, most of them young children.1 The family, social, and economic toll of these losses is intolerably high and ...entirely preventable,12 which is why we are grateful to McNally for highlighting swimming as an important but neglected area of public health.3 The World Health Organization recommends interventions to prevent drowning, including developing a national water safety plan, improving drowning data, and teaching school age children basic swimming and water safety skills.12 In the UK the National Water Forum has developed a strategy and made some important achievements,4 including developing a water incident interactive database and raising public and professional awareness. England has lost almost 400 swimming pools since 2010.5 The government should conduct an audit of swimming pools and develop a clear costed plan for increasing facilities.6 McNally’s article reminds us that swimming is a positive intervention that can be used to target a range of important public health concerns: diabetes, falls, obesity, mental health, and physical activity are just a few.37 Swimming and aquatic activity can also be extremely beneficial before and after surgery. Exercise: the miracle cure and the role of the doctor in promoting it. 2015. www.aomrc.org.uk/wp-content/uploads/2016/03/Exercise_the_Miracle_Cure_0215.pdf 9 Watson MC Lloyd J. Physical activity: manifold benefits for health and wellbeing.
Chub mackerel
Scomber japonicus
is a migratory fish widely distributed around Japan, and is an important fishery resource. However, target strength (
TS
) measurements of chub mackerel are limited, ...and the relationship between
TS
and fork length has not been fully clarified, despite its importance for the estimation of chub mackerel abundance. In this study, the
TS
–fork length (
FL
) relationship in chub mackerel was evaluated under realistic conditions.
TS
mean
and
TS
max
tended to increase with fork length at both 38 and 120 kHz, and
TS
histograms were bimodal for most individuals. In the
TS
mean
–FL
relationship, when the coefficient
a
was fixed at 20 (the standard for fish with swim bladders),
TS
cm
(standardized by the square of the fork length) was −67.9 dB (
r
2
= 0.70) at 38 kHz and −69.2 dB (
r
2
= 0.45) at 120 kHz. Additionally, the swimming angle had a peak of around 0° with a mean of −1.23°, and the mean swimming speed was 0.16
FL
/s with a standard deviation of 0.07
FL
/s.
TS
reached a maximum between −20° and 0° and then decreased drastically as the swimming angle increased or decreased. Our results have practical implications for the management of chub mackerel.
Los avances de la literatura científica en el campo del deporte han generado una tendencia creciente al desarrollo de la producción académica, el propósito de este artículo se centra en analizar la ...producción científica entre el periodo de 1960-2021 en el ámbito de la natación, a partir de la construcción de un análisis bibliométrico en la base de datos Scopus. Las ecuaciones de búsqueda se centraron en DECS (Descriptores en ciencias de la salud), con los descriptores: nadadores, swimmers male, swimming, natación carreras. Se evidencian un aumento en la producción de documentos científicos en el periodo de 2010-2020; dentro de la investigación se dio a conocer que el 86% de los documentos son de artículos de investigación, donde el 84% de estos estudios se encuentra en el ámbito de salud y fisiología deportiva, y el 6% son documentos de revisión; predominando EE.UU. y el Reino Unido como principales elaboradores de información y estudios en natación en los últimos 10 años.
Palabras claves: producción académica, bibliométrico, natación, literatura científica.
Abstract. Advances in the scientific literature in the field of sports have generated a growing trend towards the development of academic production, which is why this article focuses on analyzing scientific production between the period 1960-2021 in the field of sport. Swimming, from the construction of a bibliometric analysis in the Scopus database. The search equations focused on DECS (Descriptors in Health Sciences), with the descriptors: swimmers, swimmers male, swimming, swimming races. There is evidence of increase in the production of scientific documents in the period 2010-2020; Within the investigation, it was revealed that 86% of the documents are research articles, where 84% of these studies are in the field of health and sports physiology, and 6% are review documents; predominating the USA and the United Kingdom as the main producers of information and studies in swimming in the last 10 years.
Keywords: academic production, bibliometric, swimming, scientific literature.
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