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Marginal differences in race results between top swimmers have evoked the interest in competition-based success factors of long-term athlete development. To identify novel factors for the multi-dimensional model of talent development, the aim of the study was to investigate annual variation in competition performance (ACV), number of races per year, and age. Therefore, 45,398 race results of all male participants (n = 353) competing in individual events, i.e., butterfly, backstroke, breaststroke, freestyle, and individual medley, at the 2018 European Long-Course Swimming Championships (2018EC) were analyzed retrospectively for all 10 years prior to the championships with Pearson's correlation coefficient and multiple linear regression analysis. Higher ranked swimmers at the 2018EC showed significant medium correlations with a greater number of races per year and small but significant correlations with higher ACV in 10 and nine consecutive years, respectively, prior to the championships. Additionally, better swimmers were older than their lower ranked peers (r = −0.21, p < 0.001). Regression model explained a significant proportion of 2018EC ranking for 50 m (47%), 100 m (45%), 200 m (31%), and 400 m races (29%) but not for 800 and 1,500 m races with number of races having the largest effect followed by age and ACV. In conclusion, higher performance variation with results off the personal best in some races did not impair success at the season's main event and young competitors at international championships may benefit from success chances that increase with age. The higher number of races swum per year throughout the career of higher ranked swimmers may have provided learning opportunities and specific adaptations. Future studies should quantify these success factors in a multi-dimensional talent development model.

This work presents simulation of a Reconfigurable Spherical Robot IV for confined environment. The robot is a spherical shape with three legs kept inside spherical shell. Each leg has four degrees of freedom. All three legs can be extended for two types of locomotion such as legged locomotion and rolling sphere. A number of simulation has been done in steering in a wide and small radius of turning, rolling forward motion, and walking breaststroke concept. The simulation results show a promising concept of this new robot.

The present research investigated pacing for world-class age group swimmers competing in individual medley in 200 m and 400 m. Data on 3,242 unique finishers (1,475 women and 1,767 men) competing in four Master World Championships [XV FINA WMC held in Montreal (Canada) in 2014, the XVI FINA WMC held in Kazan (RUS) in 2015, the FINA WMC held in Budapest (HUN) in 2017, and the XVIII FINA WMC held in Gwangju (KOR] in 2019) were analyzed. Men were faster than women among all age groups in both 200 and 400 m. Additionally, differences were found between almost all adjacent age groups, with the exception (p > 0.05) of age groups 25–29 to 30–34, 35–39 to 40–44 years in 200 m races and 25–29 to 30–34, 30–34 to 35–39, 35–39 to 40–44, and 45–49 to 50–54 years in 400 m races. Men showed a higher pacing variation in 200 m among all male age groups and all female age groups up to 69 years. Pace-variation pairwise comparisons between men and women showed no consistencies throughout age groups, with the exception of a higher variation in men in age groups ≥55-year-old. Men were faster for all splits and strokes in both 200 and 400 m, and significant changes were identified for each split and stroke for both men and women in both 200 and 400 m. Front crawl (freestyle, 4th split) was the fastest butterfly (1st split), backstroke (2nd split), and breaststroke (3rd split). In summary, men were faster than women for all age groups in both 200 and 400 m. Men showed a higher pacing variation in 200 m in all age groups, where women had a higher variation in age groups up to 69 years. The fastest stroke for the final spurt was front crawl, followed by butterfly, backstroke, and breaststroke. Based on these findings, coaches should advise their master athletes to focus on the final spurt in both 200 and 400 m individual medley for a fast final race time.

The propulsive forces and instantaneous power that are generated by a swimmer have a great influence on the swimming performance. This works presents a new device, called SwimOne, for measuring propulsive force and estimating the instantaneous power of the swimmer. In addition, the detailed prototype is able to exert a customizable opposition force to the swimmer for training purpose. The conceptual idea is presented by describing the differential equation of the swimmer and the protocol for a factible estimation of the instantaneous power. The variables that are to be measured and estimated are identified and, consequently, the sensor and actuator systems can be selected. The high-level and detailed designs of the prototype are presented together with the protocol that is carried out in order to validate the sensor and actuation systems. The device is able to monitor the variables of interest of the swimmer together with the propulsive force and instant power. Finally, some experiments are carried out providing the results of several participants swimming in crawl, backstroke, butterfly, and breaststroke styles in the presence of different opposition force. The preliminary results show that SwimOne is valid for measuring instantaneous force and power with different loads in swimming.

Plivanje je bazičan sport i smatra se jednom od najkvalitetnijih aktivnosti, kad promatramo sa zdravstvenog aspekta, no nažalost, kao sport ne zauzima veliki medijski prostor poput timskih npr., nogomet, košarka, rukomet... Kroz godine, plivanje je prošlo kroz velike promjene i napredovalo u različitim segmentima, od same tehnike plivanja, sustava treninga, pa do opreme. Specifičnog je karaktera, te uz fizičku spremnost zahtijeva i posebnu psihološku crtu i upravo je to ono što plivanje izdvaja u moru sportova. Svaka sposobnost doprinosi plivanju na vlastiti način, no s obzirom na to da sam se i sama bavila ovim sportom i natjecala se posebno u prsnoj tehnici koja je i tema ovog rada, fokusirat ću se na jakost i snagu, i njihovim metodskim postupkom kod plivačica „najsporije plivačke tehnike“. Swimming is basic sport and it is considered as one of the highest quality activities when it is viewed from the health perspective. However, unfortunately, as a sport it does not take media space as much as team sports do (such as football, basketball, handball etc.). Over the years, swimming has seen enormous changes and progress in various segments, from swimming technique itself, training system, to the equipment. It is a specific sport and it requires not just physical fitness, but special psychological trait as well, which is exactly what makes it stand out in the sea of sports. Each ability contributes to swimming in a certain way, but since I was a swimmer myself and competed in breaststroke technique, which is the topic of this work, I will focus on strength and power and their methodical procedure in female swimmers performing “the slowest swimming technique”.

This study aims to develop a module for the development of freestyle swimming teaching materials using trial and error methods as a medium for learning implementation, a module for developing learning or free style swimming training to facilitate swimming trainers and as an alternative method that can be used by trainers or teachers in learning freestyle swimming. This research is a type of development research with reference to the opinion of Kaufman, (1979) which researchers have developed with the current situation, the product developed is a freestyle swimming learning or training method with a trial and error method that contains learning sequences and learning with a psychological approach to swimming students. Product development through several stages began testing learning design experts and swimming material experts, then making questionnaires validated by swimming material experts and also sports psychologists, then in field trials, testing small groups and students, testing medium groups and students and large group trials. The place for testing in the swimming pool is insan cendekia krian, the data collection technique uses a questionnaire by assessing the responses of swimming students and in analysis using descriptive statistics that are presented in percentage form. The results of this study indicate that, the product validation test by learner design experts with a percentage of 88.4% was very good, a pool material expert with a percentage of 95% was very good, in swimming student trials with a small group trial with a percentage of 84.8% very good , moderate group students with a percentage of 87.9% were very good, and large group tests with a percentage of 91.7% were very good. Thus the module for developing swimming learning using the trial and error method is feasible to be used by trainers or swimming teachers.

Pacing in swimming has been investigated in pool swimming for elite-standard and age group freestyle swimmers, but little is known about pacing in age group swimmers competing at world class level in backstroke, breaststroke, and butterfly. The aim of this study was to investigate pacing for age group swimmers competing at world class level in 100 and 200 m in the four single disciplines (freestyle, backstroke, breaststroke and butterfly). Data on 18,187 unique finishers competing in four FINA Master World Championships between 2014 and 2019 were analyzed. The sample included 3334 women and 14,853 men. Swimming speed decreased with increasing age (p &lt, 0.05). Freestyle was the fastest and breaststroke the slowest (p &lt, 0.05) stroke. Women and men were faster in 100 m (p &lt, 0.05) than in 200 m. Backstroke was the stroke with the lowest and butterfly with the highest coefficient of variation in swimming speed. One hundred meters had a higher coefficient of variation in swimming speed than breaststroke (p &lt, 0.05). For 100 m, swimming speed decreased for all strokes and all age groups during the second lap. For 200 m, swimming speed was the fastest for all strokes and all age groups during the first lap. In summary, the FINA World Masters Championships presented the unique characteristic that, when all competitors were considered, (i) swimming speed decreased with increasing age, (ii) women and men were faster in 100 m than in 200 m, (iii) freestyle was the fastest stroke and (iv) the largest increase in swimming time for 100 m all strokes and all age groups occurred during the second (out of two) lap and for 200 m, swimming speed was the fastest for all strokes and age groups during the first lap. These findings should help coaches to develop age- and event-tailored pacing strategies.

In this study, we proposed a continuous stroke phase recognition method with lower-limb inertial signals. The aim of the method was to decrease the time needed and to relieve the burdensome manual configurations in the tasks of human underwater motion recognition. The method automatically segmented the data of a period of time into stroke cycles and three sub-phases (propulsion, glide and recovery). K-nearest neighbor algorithm (k-NN) was used as the classifier to train the segmented data and classify the new data on each sample interval. To validate the proposed recognition method, three elite swimmers were recruited. We also designed an wearable sensing system for human underwater motion sensing with inertial measurement units (IMUs). With only data of 5 stroke cycles for training, the recognizer produced accurate recognition results. The average precision across the phases and the subjects was 93.7% and the average recall was 92.6%. We also investigated the time difference of the key stroke events (stroke phase transitions) between the recognized decisions and the reference ones. The average time difference was 66.2 ms, which accounted for the 4.2% of a single stroke phase. The results of the pilot study proved the feasibility of the new method for human aquatic locomotion assistance tasks. Future efforts will be paid in this new direction for more promising results.

RESUMO O objetivo desse estudo foi verificar diferenças entre a frequência cardíaca máxima (FCM) obtida na natação em testes de 200 metros nas técnicas de nado crawl e peito e comparar a FCM dos testes com as obtidas através de 53 equações de predição. A amostra foi composta por dois grupos de nadadores, todos do sexo masculino, oito (22,87 ± 2,03 anos) fizeram o nado crawl e 14 (22±2,94 anos) o nado peito. Não houve diferenças significantes (p = 0,530) em relação às técnicas de nado. Comparando-se a FCM obtida e calculada, através do modelo de Bland Altman, foi observado que apenas para o nado crawl são indicadas equações de predição para a estimativa da FCM, na impossibilidade de feitura do teste máximo. Entre as equações, recomenda-se a FCM = 204-1,07 x idade. ABSTRACT The aim of this study was to verify the differences between the Maximum Heart Rate (MHR) obtained in swimming in tests of 200 meters in two swimming strokes frontcrawl and breaststroke and to compare FCM of the tests with the obtained through 53 prediction equations. The sample consisted of two groups of swimmers, all male, 8 (22.87±2.03 years) performed freestyle and 14 (22±2.94 years) breaststroke. There were no significant differences (p=0.530) regarding the swimming strokes. Comparing the MHR obtained and calculated through the Bland Altman model, it was observed that only for freestyle are indicated prediction equations for the MHR estimation, in the impossibility of to perform a maximum test. Among the equations, the MHR = 204-1.07 x age is recommended. RESUMEN El objetivo del estudio fue comprobar las diferencias entre la frecuencia cardíaca máxima (FCM) obtenida en natación en pruebas de 200 metros en las técnicas de crol y braza, y comparar las FCM de las pruebas con las obtenidas a través de 53 ecuaciones de predicción. La muestra estaba compuesta por dos grupos de nadadores, todos del sexo masculino, y 8 (22,87 ± 2,03 años) nadaron con estilo crol y 14 (22 ± 2,94 años) nadaron a braza. No hubo diferencias importantes (p = 0,530) en relación con las técnicas de natación. En comparación con la FCM obtenida y calculada, a través del modelo de Bland Altman, se observó que las ecuaciones de predicción para la estimación de la FCM solo estaban indicadas para crol, por la imposibilidad de realizar la prueba máxima. Entre las ecuaciones, se recomienda la FCM = 204-1,07 × edad.

We use the annual ranking of the top 100 performers in the world that the Federation Internationale de Natation (FINA) publishes to study the impact the LZR Racer swimsuit and the deregulation of the use of dolphin kicking in breaststroke had on swimming performances. The swimsuit innovation, which was legal to use in 2008 and 2009, impacted performances across the sport such that improvement in the years swimmers could use any variation of the suit was significantly larger than in the years before it was created and after it was banned. The change in rules dictating legal motions swimmers could use while competing in breaststroke events, which occurred in 2015, caused improvement in breaststroke races to be significantly bigger than in races that involve the other strokes. We close by discussing the importance of FINA’s decisions on regulating technology and monitoring innovation within the sport.

The aim of this study was to compare underwater fin swimming performance using dolphin, flutter and breaststroke kicks with and without diving gear. Performance was evaluated in terms of average swimming velocity. The parameters of spatiotemporal structure of the stroke reflecting to the swimming economy were employed. Conscious modifications in propulsion technique were considered here with the aim of controlling swimming performance. A total of ten professional scuba divers swam at maximal speed underwater for 50m using each of three techniques: dolphin, flutter, or breaststroke kicks. Swimmers' performance was compared between holding their breath and using breathing apparatus. Two cameras recorded their movements in sagittal and transverse planes. The average swimming velocity (vav), stroke length (SL), stroke rate (SR), index of variation of intracycle velocity (VIVIndex) and stroke index (SI) were estimated. Relative to the other techniques, the dolphin kick without a diving gear demonstrated the highest vav and low SI and VIVIndex values, which reflects the most advantageous economy of propulsion at given velocity. Given the lack of statistical differences, using the breaststroke kick and flutter kick when swimming with a diving gear seems to be comparable to dolphin-kick in terms of average velocity and parameters reflecting the economy of propulsion. Thus, a search for fin swimming techniques with the aim of achieving specific goals seemed reasonable. The results suggest, that performance achieved while using various fin swimming techniques was probably controlled by different strategies of leg movements. These strategies revealed differences in a spatiotemporal (SR-SL) structure of the stroke and they were closely associated in terms of the velocity variation decrease.

The anaerobic threshold (AnT) seems to be not only a physiologic boundary but also a transition after which swimmers technique changes, modifying their biomechanical behaviour. We expanded the AnT concept to a biophysical construct in the four conventional swimming techniques. Seventy-two elite swimmers performed a 5×200 m incremental protocol in their preferred swimming technique (with a 0.05 m·s−1 increase and a 30 s interval between steps). A capillary blood samples were collected from the fingertip and stroke rate (SR) and length (SL) determined for the assessment of [La], SR and SL vs. velocity inflexion points (using the interception of a pair of linear and exponential regression curves). The [La] values at the AnT were 3.3±1.0, 3.9±1.1, 2.9±1 .34 and 4.5±1.4 mmol·l−1 (mean±SD) for front crawl, backstroke, breaststroke and butterfly, and its corresponding velocity correlated highly with those at SR and SL inflection points (r=0.91–0.99, p

Aerobic exercises on land could be quantified and tracked objectively, but swimming style recognition has remained unexplored. Taking the advantages of signal processing and machine learning on acceleration signals, the purpose of this study was, by analyzing swimming accelerometer data, to explore a set of algorithm in tracking swimming activities, including recognizing swimming styles, counting time and counting strokes in each style. A total of 17 participants (9 females) from the swimming team of the Southeast University of China was recruited. They performed breaststroke, front crawl, backstroke and butterfly, four 50-meter-lap each, with an ActiGraph GT9X inertia measurement unit on wrist of their preferred side. Overall, 78.7 ± 14.6, 148.5 ± 21.7, 151.2 ± 14.4, 98 ± 16.3 strokes were performed and evaluated on breaststroke, front crawl, backstroke and butterfly, respectively. In classification, three classifiers were examined and the result showed that support vector machine (SVM) provided the best accuracy of classification (over 99%). In time counting, the accuracy was over 99% and in stroke counting, the overall single-lap accuracy rate was 93.3%. In conclusion, with a combination of an objective measure and machine-learning algorithm, tracking swimming activities, including swimming style classification, counting swimming time and strokes, by a accelerometer becomes possible.

A aprendizagem de habilidades motoras pode ser promovida mediante instrução visual ou auditiva que transmite informações sobre diversas características da habilidade, tais como espaciais ou rítmicas. Para habilidades aquáticas como a pernada do nado peito, os manuais técnicos enfatizam características espaciais, negligenciando aspectos rítmicos da habilidade, apesar de a teoria da aprendizagem motora considerar o timing relativo uma característica crucial na distinção entre uma habilidade e outra. Objetivou-se analisar o impacto da instrução com e sem a informação sobre a estrutura rítmica correta, transmitida visual ou auditivamente, sobre a aprendizagem da pernada do nado peito. Cinquenta estudantes de Educação Física foram distribuídos em quatro grupos experimentais (instrução auditiva, visual, com e sem informação rítmica correta) e realizaram 400 tentativas de aquisição da pernada do nado peito, mais 50 de retenção e 50 de transferência, durante as quais foram mapeados os índices de pernada, de configuração rítmica e espacial. Os resultados mostraram índices marginalmente melhores (p=0,075), no teste de retenção, dos participantes que receberam a instrução com a informação rítmica correta, e uma forte correlação entre os índices de pernada com os de configuração rítmica ao longo de todo o processo, mas não com os de configuração espacial. Não houve diferença entre os grupos de instrução visual e auditiva. Esses resultados corroboram resultados anteriores sobre os efeitos da informação rítmica na aprendizagem de uma habilidade motora complexa, e reforçam o papel do ritmo na eficiência na execução de uma habilidade e consequentemente na sua aprendizagem. Motor learning can be fostered by visual or auditory instruction conveying information on different features of the skill, like spatial and rhythmic characteristics. For swimming skills like the breaststroke kick, manuals predominantly emphasise spatial features, neglecting rhythmic aspects – even though motor learning considers movement rhythm crucial for distinguishing one skill from another. We aimed to analyse the impact of instruction containing or not the adequate rhythmic pattern information, conveyed by visual or auditory stimulus, on learning the breaststroke kick. Fifty university students, assigned to four experimental groups (auditory, visual, with and without rhythmic information), performed 400 acquisition plus 50 retention and 50 transfer trials during which stroke index, rhythmic and spatial pattern indices and instruction request frequency were mapped. Results showed a marginal difference (p= .075) between higher indices in the retention test of participants receiving information about adequate rhythm, as well as a strong correlation between stroke index and rhythm pattern index, but not with spatial pattern index. No difference between auditory and visual groups was found. This result supports earlier research on the impact of rhythmic information on the learning of complex motor skills, and emphasises the role rhythm plays in skill efficiency and consequently in motor learning.

This study aimed to estimate the optimal body size, limb segment length, and girth or breadth ratios of 100-m breaststroke performance in youth swimmers. In total, 59 swimmers [male: n = 39, age = 11.5 (1.3) y; female: n = 20, age = 12.0 (1.0) y] participated in this study. To identify size/shape characteristics associated with 100-m breaststroke swimming performance, we computed a multiplicative allometric log-linear regression model, which was refined using backward elimination. Results showed that the 100-m breaststroke performance revealed a significant negative association with fat mass and a significant positive association with the segment length ratio (arm ratio = hand length/forearm length) and limb girth ratio (girth ratio = forearm girth/wrist girth). In addition, leg length, biacromial breadth, and biiliocristal breadth revealed significant positive associations with the 100-m breaststroke performance. However, height and body mass did not contribute to the model, suggesting that the advantage of longer levers was limb-specific rather than a general whole-body advantage. In fact, it is only by adopting multiplicative allometric models that the previously mentioned ratios could have been derived. These results highlighted the importance of considering anthropometric characteristics of youth breaststroke swimmers for talent identification and/or athlete monitoring purposes. In addition, these findings may assist orienting swimmers to the appropriate stroke based on their anthropometric characteristics.

Objective:Little is known about the transfer of swimming skills from flat, calm conditions to outdoor, unsteady conditions. The aim of the present study was to investigate the velocity decrement of several life-saving, self-rescue and rescue related strokes when introducing waves of different heights.Methods:Thirty-three subjects swam twelve 25m sprints each, in a randomized order, in a 3x4 (wave height x stroke) design. The wave heights were flat, medium (ca 20 cm) or large (ca 40 cm), in a specially designed wave-simulating pool. The strokes studied were front crawl, head-up crawl, back crawl and breaststroke. A subgroup swam front crawl, head-up crawl and head-up crawl with fins. A repeated measures ANOVA showed a significant effect of stroke, F(3,23)=108 (pResult:The conclusion is that the rank order of strokes does not change when introducing waves and that no stroke seems to perform relatively better in unsteady water compared to flat water. Other aspects than performance and velocity should be considered when choosing strokes for swimming in waves, these are discussed in the paper.

Sacrum located IMU sensors were used to monitor three-axis acceleration and three-axis rotation from elite swimmers in competition conditions. The intrastroke velocity was determined for each swimmer using their preferred swim stroke (freestyle, backstroke, and breaststroke) using three different calculation techniquesdual-axis acceleration, dual-axis acceleration eliminating the static gravity constant, and altitude and heading reference system. The mean intrastroke velocity variation (averaged over one 50-m lap) in freestyle swimming was less than 0.6 in all cases. This resulted in a timing under-estimate of less than 0.60ms for freestyle, 4.0ms for breaststroke, and a timing overestimate of less than 6.2ms for backstroke. The difference was less than 5 over the complete stroke (one way ANOVA p > 0.05), indicating no significant difference in the velocity profiles. These simple, robust analysis techniques can be used to quantify variations in every stroke as the swimmer fatigues, providing significant information to coaching staff and athletes.

The purpose of this study is to see the contribution of VO2 Max to the ability of breaststroke pool 200 M. This type of research is correlational is to see the contribution of VO2 Max to the ability of breaststroke pool 200 M. The population in this study are students of the Department of Health and Recreation Faculty of Sport Sciences University Negeri Padang in 2013 that took the swimming course totaling 112 people. Sampling technique in this research is random sampling taken 50 percent in each of the code section with the total sample result all 54 people. The data was collected by carrying out the VO2 Max test and a 200 meter breaststroke capability test. Data analysis and hypothesis testing research using simple correlation analysis technique with significant level α = 0,05. To find contributions using the formula r2 x 100 percent. Based on the results of the study, it can be seen the comparison of r count 0.382 greater than r table 0.261 then the data shows there is a relationship between VO2 Max with 200 meter breaststroke ability and also tcount 3.24 greater than ttab 1,675 showed a significant relationship between VO2 Max and a 200 meter breaststroke ability. Based on the results of the study showed the contribution of VO2 Max to the 200 meter breaststroke proficiency of the students of Department of Health Recreation FIK UNP with the percentage of 14.59 percent. Keywords: Pool Style Chest, VO2 Max

Painted Lady‘And swimming my slow breaststroke out to the channel I saw a darkwinged butterfly come flying in above the waves, moving with the breeze, heading for the dunes. Was this a migrant pain...

In the original article [...]

The breaststroke is a swimming style that is loved by everyone because it is so easy to do . The purpose of this study was to improve breaststroke swimming skills in the 2018/2019 physical education s tudy p rogram students through the application of the modified game method . The method used in this research is a classroom action research methodology research design by Kemmis and Mc.Taggart . he subjects in this study were 31 students of the PJKR study program who took the aquatic learning course II, the results of this study were from the initial test data that 8 students were in the complete category or about 26%, there was an increase in the first cycle, 20 students were included in the category. complete or about 65%, and in cycle II, there was a very large increase with 29 students in the complete category or around 94%, this research was in accordance with the set target, namely 90%. he conclusion of this study is that the application of the modified game method is effective in improving breaststroke swimming skills in physical education study program students class of 2018/2019

Introduction: Masters swimming competitions involve adults who practice swimming as a hobby, and it is focused on three main areas: fitness activity, recreational activity, and competitive activity. Masters swimming competitions are regulated at an international level by the FINA (Federation Internationale de Natation) and by the LEN (Ligue Europeenne de Natation). The Swimming Masters competitions are divided in age groups, starting at the age of 25, as follows: 25-29 years, 30-34 years, 35-39 years etc. Aim: In this paper we wish to present a study on reduction of swimming speed in relation to age, in breaststroke men competitions (50 m, 100 m, and 200 m). Methods: We analyzed the swimming speed for Masters Swimmers in a long swimming pool for the following events: 50 m, 100 m, 200 m – man breaststroke. The reference speed for each age group was calculated as the mean of the best 10 times obtained for that certain category. Results: For competitors aged 60-69 the speed decreases reaching about 80-60% of the maximum speed, and it reaches 80% of the maximum value at ages that range from 70 to 84 years old. After 85 the speed decreases up to 30% to 58% of the maximum speed. Conclusion: In breaststroke men events the speed at which master competitors swim decreases with age. Regarding the values of speed dependent on age and type of event we can state that it decreases more abruptly for older age in shorter distance events.

Purpose:To evaluate the efficacy of existing performance models to assess the progression of male and female adolescent swimmers through a quantitative and qualitative mixed-methods approach. Methods:Fourteen published models were tested using retrospective data from an independent sample of Dutch junior national-level swimmers from when they were 12–18 y of age (n = 13). The degree of association by Pearson correlations was compared between the calculated differences from the models and quadratic functions derived from the Dutch junior national qualifying times. Swimmers were grouped based on their differences from the models and compared with their swimming histories that were extracted from questionnaires and follow-up interviews. Results:Correlations of the deviations from both the models and quadratic functions derived from the Dutch qualifying times were all significant except for the 100-m breaststroke and butterfly and the 200-m freestyle for females (P < .05). In addition, the 100-m freestyle and backstroke for males and 200-m freestyle for males and females were almost directly proportional. In general, deviations from the models were accounted for by the swimmers’ training histories. Higher levels of retrospective motivation appeared to be synonymous with higher-level career performance. Conclusion:This mixed-methods approach helped confirm the validity of the models that were found to be applicable to adolescent swimmers at all levels, allowing coaches to track performance and set goals. The value of the models in being able to account for the expected performance gains during adolescence enables quantification of peripheral factors that could affect performance.

When humans take to the water, they generate sound. This is helpful for the detection, classification, localisation and tracking of certain activities for purposes of border security, health and safety of offshore industrial development, environmental management, etc. The most commonly measured acoustic quantity is pressure. Vector quantities related to particle motion, such as particle velocity and acceleration, can equally identify the activity and they carry directional information. Acoustic pressure and particle motion were measured from 10 water sports activities within an Olympic-sized pool: swimming backstroke, breaststroke, butterfly and freestyle; snorkelling with fins; kicking a boogie board with fins; paddling with alternating or simultaneous arms while lying on a surfboard; scuba-diving; kayaking and jumping into the pool. Activities that occurred at the surface and that involved repeatedly piercing the surface were the strongest sound generators. Surface activities that produced fewer bubbles and scuba-diving at depth generated less broadband power. The vector fields around water sports activities can be expected somewhat different in the open ocean from within a pool, and more research is needed to understand how marine fauna might perceive these vector quantities.

Rehabilitation robotics and Functional Electrical Stimulation (FES) are becoming more important in the rehabilitation of stroke and spinal cord injured (SCI) patients. Patient-cooperative control strategies help to only compensate for deficits and to not support too much. The application of a cable-driven arm robotic system with constant force support is considered. FES of the biceps and triceps, as well as of the posterior and anterior part of the deltoid muscle allows us to control the flexion and extension of the elbow joint and of the shoulder motion in the transversal plane. In order to support these motions of the patient, we introduce a novel assist-as-needed FES support based on iterative learning vector fields. Using this new FES control scheme, we aim to facilitate the patient’s timing and completion of the motion. The approach is evaluated in experimental trials with healthy subjects performing a breaststroke swimming motion. Starting from a patient-typical deviation of 50°, the controller automatically adapts the support by adjusting the stimulation and thereby reduces the deviation to approximately 15° within less than ten strokes.

Purpose:To investigate the muscle-activation patterns and coactivation with the support of kinematics in some of the world’s best breaststrokers and identify performance discriminants related to national elites at maximal effort.Methods:Surface electromyography was collected in 8 muscles from 4 world-class (including 2 world champions) and 4 national elite breaststroke swimmers during a 25-m breaststroke at maximal effort.Results:World-class spent less time during the leg recovery (P = .043), began this phase with a smaller knee angle (154.6° vs 161.8°), and had a higher median velocity of 0.18 m/s during the leg glide than national elites. Compared with national elites, world-class swimmers showed a difference in the muscle-activation patterns for all 8 muscles. In the leg-propulsion phase, there was less triceps brachii activation (1 swimmer 6% vs median 23.0% [8.8]). In the leg-glide phase, there was activation in rectus femoris and gastrocnemius during the beginning of this phase (all world-class vs only 1 national elite) and a longer activation in pectoralis major (world champions 71% [0.5] vs 50.0 [4.3]) (propulsive phase of the arms). In the leg-recovery phase, there was more activation in biceps femoris (50.0% [15.0] vs 20.0% [14.0]) and a later and quicker activation in tibialis anterior (40.0% [7.8] vs 52.0% [6.0]). In the stroke cycle, there was no coactivation in tibialis anterior and gastrocnemius for world champions.Conclusion:These components are important performance discriminants. They can be used to improve muscle-activation patterns and kinematics through the different breaststroke phases. Furthermore, they can be used as focus points for teaching breaststroke to beginners.

V diplomskem delu smo analizirali določene kazalce posameznih nastopov svetovnih prvakov in najboljših slovenskih plavalk in plavalcev v prsni tehniki. Želeli smo izvedeti, pri katerih kazalcih prihaja do največjih razlik. Obravnavali smo nastope na 50-, 100- in 200-metrski razdalji v prsni tehniki. Osredotočili smo se predvsem na hitrost plavanja, frekvenco zaveslajev ter dolžino zaveslaja. Vzorec testirancev se sestoji iz petih slovenskih plavalk in plavalcev ter štirih najboljših svetovnih plavalk in plavalcev v prsni tehniki. Analiza njihovih nastopov je bila opravljena s strani analitika panožnega tima Plavalne zveze Slovenije z namenskim računalniškim programom Dartfish. Na podlagi preteklih raziskav smo ugotovili, da prihaja do največjih razlik v sami hitrosti plavanja, ki je odraz kombinacije frekvence zaveslajev in dolžine zaveslaja. Pri primerjavi podatkov ni bilo enotnega trenda izstopanja le enega izmed analiziranih kazalcev ampak so se plavalci individualno razlikovali več različnih kazalcih. Nekateri najboljši slovenski plavalci oziroma plavalke so imeli nižjo frekvenco in daljšo oziroma isto preplavano ali krajšo dolžino zaveslaja, medtem ko so drugi imeli višjo frekvenco zaveslajev ter krajšo dolžino zaveslaja. Glede na vse primerjave smo prišli do sklepa, da je bolj kot posamezen kazalec, pomembno optimalno razmerje med vsemi kazalci, ki so pogoj za uspešen nastop in dober končni rezultat plavalnega nastopa. In this diploma thesis we analyzed and compared certain indicators of individual performance between world champions and the best Slovenian swimmers in breaststroke to find out what indicators make for the biggest differences. We discussed appearances at 50, 100 and 200 meters in breaststroke. We focused primarily on swimming speed, stroke rate and distance per stroke. The test sample consisted of five Slovenian swimmers and four of the world's best swimmers in breaststroke. The analysis of their performances was carried out by an analyst of the Slovenian swimming federation team with a dedicated computer program Dartfish. Based on past research, we came to the conclusion that the largest differences occur in the speed of swimming itself, which is a reflection of the combination of the stroke rate and distance per stroke. When comparing data, there was no single trend towards only one of the analyzed indicators, but swimmers individually differed in several different indicators. Some of Slovenia's best swimmers had a lower stroke rate and a longer or the same distance per stroke, while others had a higher stroke rate and a shorter distance per stroke. Based on all the comparisons, we came to the conclusion that, rather than an individual indicator, the optimal ratio between all the indicators which are essential for a successful swim performance is required.

Drops that move uphill on a gradient surface have been introduced in the past. In this paper, however, we present drops that climb a surface that does not have a gradient to begin with. In our study, Octadecylamine in Tetradecane (ODA/TD) drops were placed on either vertical or horizontal mica surfaces, and both the cases show spreading and retraction that initiate the motion of the ODA/TD drops. On horizontal surfaces, initially, the drop spreads in all directions. Then, after some time, which is a function of the solute concentration, the rear edge of the drop jerks in the direction opposite to spreading with a retraction that reminds breaststroke swimming motion: the front sides keep spreading while the back retracts, followed by the sides closing on themselves and pushing all the liquid forward which is the only place that never retracts. The front side of the drop then spreads faster in a way that reminds the circle that the arms make during breaststroke. The back and front sides of the drop continue to shrink and expand, respectively, with a net result of moving forward. The reason this motion can happen, is that the drop self-creates a local interfacial gradient at its surrounding. The direction of this self-induced interfacial gradient is against the gravity for inclined surfaces and is random if the surface is horizontal. Tilting the surface results in a local gradient that is preferentially opposite to the direction of gravity, hence the drop’s motion results in climbing up. The drop leaves behind it a surfactant covered, but otherwise dry, surface. To the best of our knowledge such a system has not been explored before.

The purpose of this research was to determine the effect of leg muscle power, maximal oxygen, and achievement motivation on breaststroke swimming athlete. This research used a survey method to see the direct relationship between height variables, leg muscle power, maximal oxygen volume, achievement motivation on breaststroke swimming athletes. The sample used 42 people who were determined by purposive male swimmers aged 15-17 years and had participated in the championship. Performed an all-out 50-m breaststroke swimming test in a 50-m pool. The data analysis technique uses path analysis. The results of the analysis of each variable have direct effects where: Body height has a positive direct effect on swimming skills (R² = 0.308), leg muscle power has a positive direct effect on swimming skills (R² = 0.548), 3) the energy cost of oxygen has an effect positive direct to swimming skills of (R² = 0.519), motivation has a positive direct effect on athlete swimming skills with (R² = 0.419). Of the five-leg muscle power variables that have the greatest influence on breaststroke, swimming speed is 54.8% the remaining 45.2% is caused by other factors such as weather conditions, mental state, nutrition, recovery and health conditions of athletes.

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.

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.

В статье представлен ряд основных стилей массовой музыки джаз, джаз-рок, различные этно-формации (в том числе балканский стиль), ска-панк, в которых роль духовых инструментов довольно значима и даже первостепенна, что имеет исторические, культурные, социальные предпосылки. Доказано, что дионисийская (демократическая, антигламурная) сущность духовых наиболее убедительно раскрывает себя в военной (армейские духовые оркестры) и развлекательной музыке (уличные, эстрадные ансамбли и брасс-бенды). Особое значение духовые инструменты обретают в отечественной рок-музыке (так называемый «русский рок»), где симбиоз блатной песни, панка, балканского бита порождает особый анархичный настрой. Вместе с тем серьезную смысловую нагрузку духовых демонстрируют музыканты легендарной российской группы «ДДТ», где целый ряд композиций включает богатый спектр звучания (архаичные кличи, священные трубные гласы, скоморошье ерничанье и др.). Активное задействование духовых инструментов, как правило, указывает на «неформатный» в контексте современного шоу-бизнеса статус коллектива, который проповедует идеологию сопротивления мировому музыкальному мейнстриму (поп-музыке), маргинальные взгляды (культ антиистеблишмента и нематериальных ценностей), поворот к исконным, корневым постулатам простонародной жизни, живому, одухотворенному звучанию музыки.