Breaststroke Swimmer Research Articles

Simulating vortex generation to investigate the propulsive and braking mechanisms of breaststroke kick using computational fluid dynamics on a breaststroke swimmer

Swimmers primarily increase their forward velocity through lower limb motion in breaststroke, making the breaststroke kick crucial for optimizing race times. Recent studies have highlighted the generation of vortices around the swimmer’s entire body to propel forward during swimming. However, the investigation of vortex generation during breaststroke kicks remains unexplored. This study aimed to reveal the propulsive and braking mechanisms of breaststroke kicks by simulating vortex generation using computational fluid dynamics (CFD). Kinematic data during the breaststroke kick and a three-dimensional digital model were collected to conduct CFD for a male breaststroke swimmer. Vortex generation was determined during one breaststroke kick from the CFD results. Vortices, which potentially induce a decrease in forward velocity, were generated by the swimmer’s lower legs and feet during the recovery phase. The swimmer generated vortices on the dorsal side of the feet and the posterior and lateral sides of the lower legs to increase the forward velocity during the out-sweep phase. The swimmer generated vortices on the lateral sides of the thighs and lower legs and the dorsal and lateral sides of the feet during the in-sweep phase to maintain forward velocity. Moreover, vortices generated from the out-sweep to the in-sweep merged and were shed backward relative to the swimming direction after the in-sweep phase. This study is the first to reveal the propulsive and braking mechanisms of breaststroke kicks by analyzing the vortex generation.

Animal design advantage from the analogy between friction and body heat loss

When a fluid accelerates as it sweeps a solid surface there are two consequences: the friction and the heat transfer (thermal contact) between fluid and solid increase simultaneously. This is known as the universal analogy between fluid friction and heat transfer. In thermal engineering these two effects are problematic because improved thermal contact is beneficial, and increased friction (i.e., pumping power) is detrimental to overall performance. In the present article we question whether the ‘analogy’ between these conflicting effects hampers the performance of animal movement. The theory focuses on warm-blooded swimmers and the effects (friction, heat transfer) that result from one change in the configuration of the body. Selected for analysis is a breaststroke swimmer. During gliding while reaching forward the ‘one change’ is from (a) legs spread apart, to (b) legs held tight together. The theory shows that the change from (a) to (b) has two consequences: greater swimming speed, and reduced body heat loss. In animal design both effects are beneficial, unlike in engineered flow systems. The analogy between fluid friction and heat transfer accelerated the evolution of animal design, and accounts for the 'divergent evolution' of fish and mammals.

Management of a High-Level Breaststroke Swimmer with Celiac Disease: A Case Report.

Management of a High-Level Breaststroke Swimmer with Celiac Disease: A Case Report.

Magnetic resonance imaging appearance of breaststroker’s knee

Breaststroker’s knee is an overuse syndrome resulting from similar repetitive movements in competitive swimmers that has been described in the orthopedic literature. The typical symptoms are medial knee pain with tenderness to palpation at the tibial collateral ligament or inferomedial patella. Despite these localizing symptoms on clinical exam, arthroscopic studies have failed to demonstrate a specific structural abnormality corresponding to this syndrome, although some have reported thickened medial synovial plica, medial-predominant synovitis or patellofemoral cartilage loss in association knee pain with breaststroke swimmers. We present a case of medial knee pain in a young breaststroke swimmer with magnetic resonance imaging (MRI) findings of marrow edema in the anterior aspect of the medial femoral condyle. To our knowledge, this is the first reported case of MRI findings in breaststroker’s knee .

Light and chemically driven molecular machines showing a unidirectional four-state switching cycle.

The imitation of macroscopic movements at the molecular level is a key step in the development of nanomachines. The challenge is the synthesis of molecules that are able to transform external stimuli into a direction-controlled mechanical movement. The more complex such motion sequences are, the more difficult is the construction of the corresponding nanomachine. Here, we present a system that demonstrates a unidirectional, four-state switching cycle that bears similar characteristics to the arm movements of a human breaststroke swimmer. Like the latter, the molecules have a torso and two arms. The arms consist of bipyridine units and can be folded and stretched by addition and removal of copper ions. The unidirectional rotation of the arms is achieved by light-induced switching of an azo unit.

An Unusual Source of Knee Pain in a Competitive Breaststroke Swimmer

Aims: The purpose of this case report is to present an unusual source of knee pain in a competitive breaststroke swimmer and review the clinical, etiologic, and radiographic features of the disease process. Presentation of Case: A 20-year-old collegiate swimmer presented with complaints of left knee pain and weakness. Physical findings of tenderness in a lateral condylar location, measurable thigh atrophy, and pain on a resisted knee extension test were present. Plain radiographs demonstrated osteochondritis dissecans of the lateral femoral trochlear groove and evidence of moderate trochlear dysplasia. Surgical findings confirmed a 3 cm by 1 cm loose osteochondritis dissecans fragment. Discussion: The knee is forcefully extended against the resistance of the water during the propulsive phase of the whip kick used by breaststroke swimmers. This movement results in high lateral patellofemoral contact loads and increased lateral patellar

The R & D of a Swimmer Training Speed Navigator Based on the 13th FINA World Championships

The distribution of a swimmer's stamina in competitive 200 m race is very important. The performance depends not only on a swimmer's capability, but also on the strategy of stamina allocation across the four segments. In the present research, athletes who had participated in 200 m items in the 13th FINA World championships (2009, Rome) were allocated into three groups based on their performance, and these groups were top-elite swimmers (top 3 in finals), mid-elite swimmers (top 16 in heats) and lower-elite swimmers (bottom 12 in heats) respectively. Data of the segmental time and the time ratios (the percentage of segmental time in one's total time) of the three groups were analyzed. The results showed that the first and second segmental time ratios (STRs) of the top- and mid-elite groups were relatively larger than those of the lower-elite group. But the situation of the last two STRs was opposite. SONI Rebecca (a very famous USA breaststroke swimmer) missed medals of her strongest 200 m breaststroke event due to her too fast velocity in the first and second segments. These suggested that only the proper allocation of four STRs in 200 m items could bring athletes to their highest performance. So it is very important to optimizing the mode of time allocation during daily training, especially for the gifted swimmers lacking experiences.Based on the above research results, we developed a navigation system for regulating athlete's swimming speed during training. The system was composed of 15 watertight LED lamps laying on the bottom of the pool, a computer, a control unit, a starting unit with speaker, and other components. It can modulate the timing and duration of every LED lamp. The course of a swim training session could be guided by the lighting timing of each lamp in turn and therefore could be converted into a parameter file. Coaches could compile the parameter file to obtain desired training speed for the very athlete. And the athlete could regulate his/her speed according to the clue of the lamps controlled by the navigator. For instance, if the lamp ahead of the athlete was illuminated, it meant their speed was too low. If the illuminated lamp was just under the athlete's face, it meant the speed of the athlete was the desired one. All kinds of distance training course could be navigated by the system. It could not only guild a single training course, but could also perform several training sessions which demand strict intervals. It will save considerable amount of energy and time of coaches and improve their training efficiency. It has been authorized the invention

Cell-body rocking is a dominant mechanism for flagellar synchronization in a swimming alga

The unicellular green alga Chlamydomonas swims with two flagella that can synchronize their beat. Synchronized beating is required to swim both fast and straight. A long-standing hypothesis proposes that synchronization of flagella results from hydrodynamic coupling, but the details are not understood. Here, we present realistic hydrodynamic computations and high-speed tracking experiments of swimming cells that show how a perturbation from the synchronized state causes rotational motion of the cell body. This rotation feeds back on the flagellar dynamics via hydrodynamic friction forces and rapidly restores the synchronized state in our theory. We calculate that this "cell-body rocking" provides the dominant contribution to synchronization in swimming cells, whereas direct hydrodynamic interactions between the flagella contribute negligibly. We experimentally confirmed the two-way coupling between flagellar beating and cell-body rocking predicted by our theory.

Analysis of speed, stroke rate, and stroke distance for world-class breaststroke swimming

Speed in aquatic locomotion is determined by stroke distance and stroke rate, but it does not always follow that an increase in stroke rate will lead to an increase in speed. Kleshnev (2006) developed a method to evaluate the relationship between speed and stroke rate during rowing – the effective work per stroke. In this case study, the effective work per stroke was determined for a male world-class 100-m breaststroke swimmer for seven races in major championships and compared between: each of the seven races; each quarter within each race; and the best swims of this case study and seven other world-class swimmers. The effective work per stroke was related to race performance, with the fastest race having the highest effective work per stroke and lowest stroke rate, with slower races having low effectiveness and high stroke rate (R 2 = 0.85). The effective work per stroke was reduced in a race as the swimmer fatigued. The within-race standard deviation of effectiveness was lower in fast swims (R 2 = 0.84). This analysis has identified some characteristics of fast swimming: high effectiveness, optimal stroke rate, and a flat effectiveness profile. Training and racing strategies can now be devised to improve performance by increasing the sensitivity of assessment of strengths and weaknesses in individuals.

FROG SWIMMERS KICK AND ROW

![Figure][1] If you're a breaststroke swimmer, you might think you know all about frog swimming. But take a closer look and you'll find that there's a lot more going on. For a start, many frog swimmers do more than simply push off with their legs; some row with their paddle-like feet by

Interpretation of the Physiological Monitoring of an International Swimmer

It remains contentious whether improvements in the swimming speed at various lactate concentrations coincide with improvements in competitive performances. A lack of longitudinal data exists to confirm this premise. This case study presents data for a world-class 200-m male breaststroke swimmer from a sports science support programme over a three-year period. Eleven (7 × 200-m) Step tests were undertaken during this period Seven of the Step tests occurred within two-three weeks of a competition performance. Rank order correlation demonstrated that higher race speeds coincided significantly (P 0.1) with higher speeds at blood lactate concentrations of 4 mM (ρ = 0.95), 6 mM (ρ = 1), 8 mM (ρ = 0.95). Data were observed to fluctuate following periods of overreaching, detraining and also due to poor nutritional practice. It was concluded that changes in the speed at various blood lactate concentrations can inform the coaching process, but only when measured alongside other parameters and where an in-depth knowledge of the swimmer's health and training status is available.

Estimating propulsive forces in swimming from three‐dimensional kinematic data

Propulsive forces are important determinants of swimming performance. The aim of this study was to quantify the measurement error (uncertainty) in propulsive forces calculated from kinematic data. Ten operators digitized underwater video recordings of a breaststroke swimmer's right arm action. Four landmarks on the hand were digitized at 50 Hz and their three-dimensional coordinates obtained using a DLT algorithm. Two angles (alpha and psi) defining the orientation of the hand relative to the fluid flow were calculated following the procedures of Schleihauf et al. (1983). The hydrodynamic force acting on the hand (FR) was calculated using the force coefficients of Schleihauf (1979). Errors in single measurements of hand speed, alpha and psi were estimated for each video field analysed. Errors in alpha and psi led to average errors in the lift and drag coefficients of 27 and 20% respectively, which, when combined with an average hand speed error of 6%, produced an average error in FR of 26%. Each of these errors was reduced by a factor of square root 10 when the mean of 10 measurements was used to calculate FR. Researchers should report both the estimated errors in their hydrodynamic data and the procedures used to reduce them.

The normal and the painful shoulders during the breaststroke. Electromyographic and cinematographic analysis of twelve muscles.

The purpose of this study was to describe and compare electrical activity patterns in 12 shoulder muscles during the breaststroke in 25 competitive swimmers who had normal shoulders and in 14 who had painful shoulders while they performed this stroke in a pool. The electromyographic analysis was synchronized with high-speed cinematography to discern phases of the breaststroke. Means, standard deviations, and t-tests were done for each phase. The differences in muscle activity between the two groups of swimmers demonstrated an increase in the internal rotators in the group with painful shoulders. They also demonstrated a decrease in the teres minor, supraspinatus, and the upper trapezius muscles. These factors increase the risk of impingement. Both the serratus anterior and teres minor muscles in the swimmers with normal shoulders consistently fired at or above 15% manual muscle test throughout the breaststroke cycle and were thus subject to fatigue. Based on these results, exercises for the breaststroke swimmer should be directed toward endurance training of the serratus anterior and teres minor muscles while balancing the internal and external rotators of the shoulder as well as the deltoid and supraspinatus muscles.

Hydrodynamic pressures in the propulsion of the elite breaststroke swimmer

Hydrodynamic pressures in the propulsion of the elite breaststroke swimmer

Breaststroke swimmer's knee. A biomechanical and arthroscopic study.

The cause of the breaststroke swimmer's knee with medial pain of the knee joint has not been clearly identified. Breaststroke swimmers with knee pain were, therefore, examined arthroscopically. None showed any other disorders of their knees than medial synovitis in seven of nine swimmers. Since structural abnormalities could be ruled out, biomechanical analyses utilizing cinematographic techniques were used to study patients swimming in a special flume with the speed set at 90% of their best competitive performance. The results indicate that the extension and flexion and also in some cases the hip abduction and adduction movements of the whip kick were performed with high peak angular velocities. No significant differences in swimming technique among the six patients studied and three controls could be observed. It is concluded that a combination of high angular velocities at the hip and knee and external rotation of the tibia relative to the femur repeated in excessive amounts might be the primary cause for the medial synovitis documented in these patients. The breaststroker's knee thus seems to be an overuse syndrome.

A Bibliography of Song Sheets Sports and Recreations in American Popular Songs: Part II

There will be some who remember that Part II of this Bibliography, published in September 1950, listed compositions devoted to three of the more popular competitive out-door sports-baseball, football, and outdoor swimming. While working on that installment, a certain number of songs and piano pieces celebrating other sports kept turning up, but their quantity did not seem alarming, and it was supposed that all the other competitive sports could easily be covered in this present installment. When we finally settled down to assembling the data, however, several rather unexpected factors began to manifest themselves. For one thing, the fear regarding a paucity of material in certain categories was more than borne out. Although swimming indoors in a pool is an extremely popular sport, not a single sheet could be found singing the praises of the champion breast stroke swimmer, the joys of swimming on one's back, or the speed developed with the Australian crawl. Only one sheet each was found devoted to hockey, fencing, La Crosse, and mountain climbing, and only three sheets to wrestling. In view of what TV has done for wrestling, this last failure of the song writers of the country would seem utterly inexplicable, if it were not thrown completely into the shade by the situation in regard to basketball. Basketball has long been one of the most popular of all the minor sports from grammar school days through college. And yet the reader will find by turning to the pertinent section the depths to which we have been forced in order to include the name of the game in this list at all. The ultimate insult to a noble form of exercise comes when Carl Wilhelm Kern uses