Search

The article presents a study which identifies contribution percentage of some physiological variables (dimensions and thickness) of heart muscle left and right ventricles in junior swimmers. Topics include measurements to assess heart muscle through Echocardiography; free style swimming opted by swimmers; and swimming training program consisting of (16) training weeks.

The variability of electromyographic (EMG) recordings between and within participants is a complex problem, rarely studied in swimming. The importance of signal normalization has long been recognized, but the method used might influence variability. The aims of this study were to: (i) assess the intra-individual variability of the EMG signal in highly skilled front crawl swimmers, (ii) determine the influence of two methods of both amplitude and time normalization of the EMG signal on intra-individual variability and of time normalization on muscle activity level and (iii) describe the muscle activity, normalized using MVIC, in relation to upper limb crawl stroke movements. Muscle activity of rectus abdominis and deltoideus medialis was recorded using wireless surface EMG in 15 adult male competitive swimmers during three trials of 12.5 m front crawl at maximal speed without breathing. Two full upper limb cycles were analyzed from each of the swimming trials, resulting in six full cycles used for the intra-individual variability assessment, quantified with the coefficient of variation (CV), coefficient of quartile variation (CQV) and the variance ratio (VR). The results of this study support previous findings on EMG patterns of deltoideus medialis and rectus abdominis as prime mover during the recovery (45% activity relative to MVIC), and stabilizer of the trunk during the pull (14.5% activity) respectively. The intra-individual variability was lower (VR of 0.34–0.47) when compared to other cyclic movements. No meaningful differences were found between variability measures CV or VR when applying either of the amplitude or the time normalization methods. In addition to reporting the mean amplitude and standard deviation, future EMG studies in swimming should also report the intra-individual variability, preferably using VR as it is independent of peak amplitude, provides a good measure of repeatability and is insensitive to mean EMG amplitude and the degree of smoothing applied. [ABSTRACT FROM AUTHOR]

The purpose of this study was to determine whether the breathing action in front crawl (FC) sprint swimming affects the ipsilateral upper limb kinematics relative to a non-breathing stroke cycle (SC). Ten male competitive swimmers performed two 25 m FC sprints: one breathing to their preferred side (Br) and one not breathing (NBr). Both swim trials were performed through a 6.75 m 3 calibrated space and recorded by six gen-locked JVC KY32 CCD cameras. A paired t -test was used to assess statistical differences between the trials, with a confidence level of p <0.05 accepted as significant. Swimmers were slower (3%) when breathing. Within the entry phase, swimmers had a slower COM horizontal velocity (3.3%), less shoulder flexion (8%), abduction (33%) and roll (4%) when breathing. The pull phase was longer in duration (14%) swimmers had a shallower hand path (11%), less shoulder abduction (11%), a slower hand vertical acceleration (30%) and slower centre of mass (COM) horizontal velocity (3%) when breathing. In the push phase, swimmers had a smaller elbow range of motion (ROM) (38%), faster backwards hand speed (25%) and faster hand vertical acceleration (33%) when breathing. Swimmers rolled their shoulders more (12%) in the recovery phase when breathing. This study confirms that swim performance is compromised by the inclusion of taking a breath in sprint FC swimming. It was proposed that swimmers aim to orient their ipsilateral shoulder into a stronger position by stretching and rolling the shoulders more in the entry phase whilst preparing to take a breath. Swimmers should focus on lengthening the push phase by extending the elbow more and not accelerating the hand too quickly upwards when preparing to inhale. [ABSTRACT FROM AUTHOR]

The aim of this study was to investigate the evolution of kinematic hand parameters (sweepback angle, angle of attack, velocity, acceleration and orientation of the hand relative to the absolute coordinate system) throughout an aquatic stroke and to study the possible modifications caused by a variation of the swimming pace. Seventeen competitive swimmers swam at long distance, middle distance and sprint paces. Parameters were calculated from the trajectory of seven markers on the hand measured with an optoelectronic system. Results showed that kinematic hand parameters evolve differently depending on the pace. Angle of attack, sweepback angle, acceleration and orientation of the hand do not vary significantly. The velocity of the hand increases when the pace increases, but only during the less propulsive phases (entry and stretch and downsweep to catch). The more the pace increases and the more the absolute durations of the entry and stretch and downsweep to catch phases decrease. Absolute durations of the insweep and upsweep phases remain constant. During these phases, the propulsive hand forces calculated do not vary significantly when the pace increases. The increase of swimming pace is then explained by the swimmer's capacity to maintain propulsive phases rather than increasing the force generation within each cycle. [ABSTRACT FROM AUTHOR]

The connections between swimming technique and the fluid dynamical interactions they generate are important for assisting performance improvement. Computational fluid dynamics (CFD) modeling provides a controlled and unobtrusive way for understanding the fundamentals of swimming. A coupled biomechanical-smoothed particle hydrodynamics (SPH) fluid model is used to analyze the thrust and drag generation of a freestyle swimmer. The swimmer model was generated using a three-dimensional laser body scan of the athlete and digitization of multi-angle video footage. Two large distinct peaks in net streamwise thrust are found during the stroke, which coincide with the underwater arm strokes. The hand motions generate vortical structures that travel along the body toward the kicking legs and the hands are shown to produce thrust using both lift and drag. These findings advance understanding of the freestyle stroke and may be used to improve athlete technique. [ABSTRACT FROM AUTHOR]

Biomechanical characteristics such as stroke rate and stroke length can be used to determine the velocity of a swimmer and can be analysed in both a swimming pool and a flume. The aim of the present preliminary study was to investigate the differences between the acceleration data collected from a swimming pool with that collected from a flume, as a function of the swimmer's stroke rate and stroke count, with the objective of identifying the impact on the swimmer's performance. The differences were determined by the analysis of the stroke's features, comparing several strokes normalized to one stroke count from an elite swimmer. Triaxial accelerometer logging using a sensor located in an arm band positioned immediately in the wrist was used to record the swimmer's stroke. There is statistical evidence that show that there are small differences between the pool and flume on medio-lateral wrist movements (0.64 < r < 0.75). The correlation coefficients are (0.75 < r < 0.83) and (0.82 < r < 0.89) for the other two axes. [ABSTRACT FROM AUTHOR]

Investigating the performance of an athlete and monitoring them is important to athletes and coaches because it can provide information about the training progress and injury recovery. Coaches are not always on side when athletes doing their training, so a device which is small and easy to use will increase the monitored training sessions significantly and allow the athlete to compare multiple training sessions. This technology has seen rapid development over the last years and is now available in very small sizes which have little effect on the swimmer. Using this kind of sensor, kinematics can be measured and extracted for stroke characteristics investigations. This research used an sacrum mounted self-developed inertial sensor, providing a triaxial accelerometer, gyroscope and RF capability in a waterproof casing to investigate the arm symmetry and swimming velocity in freestyle swimming. The recorded data were filtered using a high-pass Hamming windowed FIR filter to remove the gravity components from the wanted signal. The acceleration signal was then processed to find the velocity of the swimmer. A zero-crossing detection algorithm was used to investigate the arm symmetry and to find the individual stroke rates (SR), the differences between left and right arm stroke durations and the left and right arm stroke velocities (asymmetry). The investigation of the left and right arm velocity patterns of each individual swimmer allowed the investigation of each swimmers asymmetry in propulsion and velocity for the individual arms. The results of the mean lap velocities showed that the two different methods agree with an R 2 of 0.92. Furthermore a conducted Bland-Altman analysis showed a low bias of -0.04 with an upper limit of agreement of 0.03 and a lower limit of agreement of -0.11. [ABSTRACT FROM AUTHOR]

The objective of this study was to improve the stability of crawl swimming for the swimming humanoid robot. The swimming humanoid robot had 24 servo motors for the whole body and could perform basic human swimming motion. This robot can swim freely by the crawl stroke. However, the robot sometimes changed the propulsive direction while free swimming. The change in the propulsive direction was caused by instability of body rolling. Therefore, swimming motion which could change propulsive direction and roll angle amplitude was examined by simulation. Effectiveness of the devised motion was confirmed by a free-swimming experiment. [ABSTRACT FROM AUTHOR]

Copyright of Facta Universitatis: Series Physical Education & Sport is the property of Facta Universitatis, Series Physical Education & Sport and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Purpose. Sometimes the initiation phase into swimming is neglected in favor of the learning phase, which constitutes a methodical error. During the learning phases swimming trainers and instructors rely on a series of exercises. These can be completely different from one another. Methods. We have exercises that are extensive in nature and exercises that are repetitive in nature, used even during the perfecting phase and test exercises (be it test or control). Results. Thus, by structuring the exercises and methodical means used in teaching swimming, I have achieved an important didactic work aimed at helping swimming coaches and instructors as well as students from the faculty of physical education. [ABSTRACT FROM AUTHOR]

Background: This study investigated swimming speeds and sex differences of finalists competing at the Olympic Games (i.e. 624 female and 672 male athletes) and FINA World Championships (i.e. 990 women and 1008 men) between 1992 and 2013. Methods: Linear, non-linear and multi-level regression models were used to investigate changes in swimming speeds and sex differences for champions and finalists. Results: Regarding finalists in FINA World Championships and Olympic Games, swimming speed increased linearly in both women and men in all disciplines and race distances. Male world champions' swimming speed remained stable in 200 m butterfly, 400 m, 800 m and 1,500 m freestyle. Considering women, swimming speed remained unchanged in 50 m and 400 m freestyle. In the Olympic Games, swimming speed of male champions remained unchanged in 200 m breaststroke, 50 m, 400 m, 800 m and 1,500 m freestyle. Female Olympic champions' swimming speed remained stable in 100 m and 200 m backstroke, 100 m butterfly, 200 m individual medley, 50 m and 200 m freestyle. Evaluating sex differences between finalists in FINA World Championships, results showed a linear decrease in 100 m breaststroke and 200 m butterfly and a non-linear increase in 100 m backstroke. In finals at the Olympic Games, the sex difference decreased linearly for 100 m backstroke, 400 m and 800 m freestyle. However, a linear increase for 200 m butterfly can be reported. Considering Olympic and world champions, the sex difference remained stable in all disciplines and race distances. Conclusion: Swimming speed of the finalists at the Olympic Games and FINA World Championships increased linearly. The top annual female swimmers increased swimming speed rather at longer race distances (i.e. 800 m and 1,500 m freestyle, 200 m butterfly, and 400 m individual medley), whereas the top annual male swimmers increased it rather at shorter race distances (i.e. 100 m and 200 m freestyle, 100 m butterfly, and 100 m breaststroke). Sex difference in swimming was unchanged in Olympic and world champions. Finalists and champions at the Olympic Games and FINA World Championships reduced the sex difference with increasing race distance. [ABSTRACT FROM AUTHOR]

Abstract: The objective of this study was to clarify the effect of bubbles on thrust by means of an underwater robot arm. The underwater robot arm had five degrees-of-freedom (three for the shoulder and two for the elbow) which were actuated by five electric motors. The size was almost the same as human. On the top of the robot, a dynamometer was installed to measure the thrust. The robot arm was mounted in a circulating water tank. Two types of stroke of the crawl, that is, I-shaped and S-shaped, were performed. In order to distribute artificial bubbles around the arm, an elastic porous stick was attached to the arm. The stick was connected to an air compressor. Two attaching positions of the stick, that is, palm side and the back side of the palm, were tested. The following findings were obtained from the experiment: For the I-shaped stroke, the effect of bubbles became significant when the thrust became maximum. The thrust decreased when the porous stick was attached to the back side of the palm. On the other hand, the thrust increased when the stick was attached to the palm side. For the S-shaped stroke, the effect of bubbles exhibited more complicated behavior than for the I-shaped stroke, and clear tendency of the effect could not be seen. [Copyright &y& Elsevier]

Abstract: It is known that swimming equipment (suit, cap and goggles) can affect the total resistance of a swimmer, and therefore impact the resulting swimming speed and race time. After the 2009 swimming world championships (WC) the international swimming federation (FINA) banned a specific type of full body suit, which resulted in an increase in race times for subsequent WC events. This study proposes that the 2009 suits provided a reduction in swimming resistance and aims to quantify this resistance reduction for male and female freestyle events. Due to the practical difficulties of testing a large sample of swimmers a simulation approach is adopted. To quantify the race time improvement that the 2009 suits provided, an equivalent 2009 “no-suit” dataset is created, incorporating the general trend of improving swimming performance over time, and compared to the actual 2009 times. A full race simulation is developed where the start, turn, underwater and surface swimming phases are captured. Independent resistance models are used for surface and underwater swimming; coupled with a leg propulsion model for underwater undulatory swimming and freestyle flutter kick, and a single element arm model to simulate freestyle arm propulsion. A validation is performed to ensure the simulation captures the change in swimming speed with changes to resistance and is found to be within 5% of reality. Race times for an equivalent “no-suit” 2009 situation are simulated and the total resistance reduced to achieve the actual 2009 race times. An average resistance reduction of 4.8% provided by the 2009 suits is identified. A factor of 0.47 ± 10%, to convert resistance changes to freestyle race time changes is determined. [Copyright &y& Elsevier]

Background: Poor freestyle stroke biomechanics is a suggested risk factor for shoulder pain and pathology, but this has not been proven in biomechanical or clinical studies. Furthermore, the prevalence of these theoretical errors has not been identified, which would help coaches, athletic trainers, and researchers determine the most appropriate errors to focus on and develop interventions. Hypothesis: The majority of swimmers will present with at least 1 freestyle stroke error. Study Design: Cross-sectional study. Level of Evidence: Level 4. Methods: Stroke biomechanics for 31 swimmers from a collegiate swimming team were captured using underwater/abovewater cameras. Each video was evaluated for biomechanical errors: a dropped elbow during the pull-through phase, a dropped elbow during the recovery phase, an eyes-forward head-carrying angle, incorrect hand position during hand entry, incorrect hand entry angle, incorrect pull-through pattern, and inadequate body roll. Error prevalence was calculated, and relationships among the errors were evaluated using chi-square statistics. Results: A dropped elbow during the pull-through phase (61.3%) and a dropped elbow during the recovery phase (53.2%) had the highest prevalence. A dropped elbow during the recovery phase was significantly associated with a thumb-first hand entry angle (P = 0.027) and incorrect hand entry position (P = 0.009). An eyes-forward head-carrying angle was associated with an incorrect pull-through pattern (P = 0.047). Conclusion: Biomechanical errors potentially detrimental to the shoulder are prevalent among swimmers. Many of the errors were interrelated, suggesting that one error may lead to other errors. Clinical Relevance: These errors highlight the need for proper stroke instruction and evaluation to decrease the risk of shoulder injury in competitive swimmers. [ABSTRACT FROM AUTHOR]

Background The purpose of the present study was to analyse potential changes in performance of elite breaststroke swimmers competing at national and international level and to compare to elite freestyle swimming performance. Methods Temporal trends in performance of elite breaststroke swimmers were analysed from records of the Swiss Swimming Federation and the FINA (Fédération Internationale de Natation) World Swimming Championships during the 1994-2011 period. Swimming speeds of elite female and male breaststroke swimmers competing in 50 m, 100 m, and 200 m were examined using linear regression, non-linear regression and analysis of variance. Results of breaststroke swimmers were compared to results of freestyle swimmers. Results Swimming speed in both strokes improved significantly (p < 0.0001-0.025) over time for both sexes, with the exception of 50 m breaststroke for FINA men. Sex differences in swimming speed increased significantly over time for Swiss freestyle swimmers (p < 0.0001), but not for FINA swimmers for freestyle, while the sex difference remained stable for Swiss and FINA breaststroke swimmers. The sex differences in swimming speed decreased significantly (p < 0.0001) with increasing race distance. Conclusions The present study showed that elite male and female swimmers competing during the 1994- 2011 period at national and international level improved their swimming speed in both breaststroke and freestyle. The sex difference in freestyle swimming speed consistently increased in athletes competing at national level, whereas it remained unchanged in athletes competing at international level. Future studies should investigate temporal trends for recent time in other strokes, to determine whether this improvement is a generalized phenomenon. [ABSTRACT FROM AUTHOR]

This study aims to clarify the mechanisms by which unsteady hydrodynamic forces act on the hand of a swimmer during a crawl stroke. Measurements were performed for a hand attached to a robotic arm with five degrees of freedom independently controlled by a computer. The computer was programmed so the hand and arm mimicked a human performing the stroke. We directly measured forces on the hand and pressure distributions around it at 200 Hz; flow fields underwater near the hand were obtained via 2D particle image velocimetry (PIV). The data revealed two mechanisms that generate unsteady forces during a crawl stroke. One is the unsteady lift force generated when hand movement changes direction during the stroke, leading to vortex shedding and bound vortex created around it. This bound vortex circulation results in a lift that contributes to the thrust. The other occurs when the hand moves linearly with a large angle of attack, creating a Kármán vortex street. This street alternatively sheds clockwise and counterclockwise vortices, resulting in a quasi-steady drag contributing to the thrust. We presume that professional swimmers benefit from both mechanisms. Further studies are necessary in which 3D flow fields are measured using a 3D PIV system and a human swimmer. [ABSTRACT FROM AUTHOR]

While many ectothermic species can withstand prolonged fasting without mortality, food deprivation may have sublethal effects of ecological importance, including reductions in locomotor ability. Little is known about how such changes in performance in individual animals are related to either mass loss during food deprivation or growth rate during re-feeding. This study followed changes in the maximum sprint swimming performance of individual European sea bass, Dicentrarchus labrax, throughout 45 days of food deprivation and 30 days of refeeding. Maximum sprint speed did not show a significant decline until 45 days of food deprivation. Among individuals, the reduction in sprinting speed at this time was not related to mass loss. After 30 days of re-feeding, mean sprinting speed had recovered to match that of control fish. Among individuals, however, maximum sprinting speed was negatively correlated with growth rate after the resumption of feeding. This suggests that the rapid compensatory growth that occurs during re-feeding after a prolonged fast carries a physiological cost in terms of reduced sprinting capacity, the extent of which shows continuous variation among individuals in relation to growth rate. The long-term repeatability of maximum sprint speed was low when fish were fasted or fed a maintenance ration, but was high among control fish fed to satiation. Fish that had been previously food deprived continued to show low repeatability in sprinting ability even after the initiation of ad libitum feeding, probably stemming from variation in compensatory growth among individuals and its associated negative effects on sprinting ability. Together, these results suggest that food limitation can disrupt hierarchies of maximum sprint performance within populations. In the wild, the cumulative effects on locomotor capacity of fasting and re-feeding could lead to variable survival among individuals with different growth trajectories following a period of food deprivation. [ABSTRACT FROM AUTHOR]

The main purpose of this study was to analyze tactical solutions used by swimmers, the finalists of the 19th Beijing Olympics in 2008, in individual front crawl events at distances of 50, 100 and 200 m. Observations were carried out on 7 swimmers, the Beijing Olympics medalists competing in front crawl individual events. Detailed analyses were run on: 1) Sports results obtained by the finalists at distances of 50, 100 and 200 m front crawl; 2) block time; 3) results of each 50 m lap time (100 and 200) called split times except 50 m front crawl (there is no split time in 50 m); and 4) the mean swimming speed (V) on individual laps of the analyzed races. To determine the correlation between the response time, the time of individual laps, and the final time of the analyzed front crawl races, Pearson's linear correlation coefficient r was obtained. As a result of detailed analyses of the test material it is believed that not only tactics for an individual race is important, but equally significant is to elaborate the strategy for the whole event and to prepare the swimmer to compete in the system of heats, semifinals and finals. However, some of the following tactical objectives can be formulated: sprinters (a distance of 50 and 100 m front crawl) should start at maximum speed, according to their abilities, and try to maintain that speed until the end of the race; middle-distance swimmers (200 m front crawl) should adopt the most optimal tactical solutions characterized by increasing speed in the second half of the distance. [ABSTRACT FROM AUTHOR]

The Critical velocity (Vcrit) represents a holistic swimming fatigue threshold and critical stroke rate is thought to coincide with Vcrit. Whether Vcrit, and in-turn critical stroke rate, also represent an inspiratory muscle fatigue threshold is not known. Following the determination of Vcrit and critical stroke rate via a two-parameter 200-m and 400-m model, 17 well-trained competitive swimmers (9 males and 8 females) undertook three experimental 200-m front crawl (FC) swims on separate occasions. One experimental swim corresponded to Vcrit, one was 5% slower than Vcrit (Vcrit5%+) and one 5% faster (Vcrit5%-) than Vcrit. Swim time, inspiratory and expiratory mouth pressure (PImax and PEmax, respectively), stroke rate, stroke length and breathing frequency were recorded during each experimental swim and were compared between swims as well as between genders. Baseline PImax and PEmax did not differ between experimental swims or genders. Although PEmax decreased significantly by a similar magnitude after each swim (range 5-8%), PImax was significantly lower in response to swimming at Vcrit (7%) and Vcrit5%- (22%) thus indicating inspiratory muscle fatigue. However, the difference in magnitude between velocities was not significant. Only stroke rate and relative swimming velocity were significantly related to the fall in PImax and no correlations were observed between PEmax and any other variable. The development of inspiratory muscle fatigue at and above Vcrit is consistent with substantial swim induced metabolic strain with the response similar between males and females. Our data suggest that Vcrit represents a FC inspiratory muscle fatigue threshold when using this two-parameter Vcrit model. [ABSTRACT FROM AUTHOR]

Abstract: Objectives: Existing work using dry land exercise-related activities has shown that the careful application of music can lead to a range of benefits that include enhanced affect, lower perceived exertion, greater energy efficiency, and faster time trial performances. The purpose of this study was to assess the psychological, psychophysical, and ergogenic effects of asynchronous music in swimming using a mixed-methods approach. Design: A mixed-model design was employed wherein there was a within-subjects factor (two experimental conditions and a control) and a between-subjects factor (gender). The experimental component of the study was supplemented by qualitative data that were analysed using inductive content analysis. Methods: Twenty six participants (M age = 20.0 years, age range: 18–23 years) underwent a period of habituation with Speedo Aquabeat MP3 players prior to the experimental phase. They were then administered two experimental trials (motivational and oudeterous music at 130 bpm) and a no-music control, during which they engaged in a 200-m freestyle swimming time trial. Results: Participants swam significantly faster when exposed to either music condition relative to control (p = .022, ). Moreover, the music conditions were associated with higher state motivation (p = .016, ) and more dissociative thoughts (p = .014, ). Conclusions: Findings supported the hypothesis that the use of asynchronous music during a high-intensity task can have an ergogenic effect; this was in the order of 2% when averaged out across the two experimental conditions. The use of music, regardless of its motivational qualities, resulted in higher self-reported motivation as well as more dissociative thoughts. [Copyright &y& Elsevier]

Abstract: 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. [Copyright &y& Elsevier]

Abstract: This paper presents the novel application of a technique for measuring flow around the hand during a simulated swim stroke with a view to enable a better understanding of propulsion generation in swimming. The technique relies on the instantaneous, non-intrusive, volumetric measurement of 3D velocity fields using a commercially available optical measurement system. A hand and forearm model was towed through a water tank to replicate the pull phase with fluid flow data being captured at regular intervals in a fixed volume through which the model moved. The measurement system included a single body, three-sensor probe for capturing pairs of images which were then processed to determine particle velocities and to characterise the flow. The results were used to investigate changes in mean velocity for six experimental cases based on three different angles of attack and two towing speeds. The results showed that the V3V system could be used to capture velocity data around the hand and for a 45° increase in angle of attack, the velocity magnitude of the flow reduced by half, indicating the presence of lift forces. [Copyright &y& Elsevier]

The decrease in swimming performance ( v) that occurs with age is a not only consequence of the physiological decrease in maximal metabolic power ( $${\dot{E}}_{\it max}$$) but can also be expected to depend on an increase in the energy cost of swimming ( C) $${\nu}_{\rm max} = {\dot {E}}_{\rm max}/C.$$ In turn, for a given speed and stroke C = W / (ηη) where W is hydrodynamic resistance, η is propelling efficiency and η is overall efficiency. The aim of this study was to measure C in 47 male masters (31-85 years old) swimming the front crawl at sub-maximal, aerobic, speeds. During the experiments propelling efficiency and projected frontal area ( A, an index of W) were also determined by kinematic analysis. 'Elder' masters (60-80 years) swam at a significantly slower pace (0.65 vs. 0.91 m s), with a lower η (0.23 vs. 0.31) and a larger A (0.39 vs. 0.23 m) than 'younger' masters (30-60 years). No significant differences in C (1.45 kJ m, on the average) were observed as a function of age or speed, but C values were significantly higher than those assessed in young elite swimmers at the very same speeds; the difference increasing with age with a rate of 0.75 % per year. With the due considerations (in this study the observed changes in η, A and C can be either attributed to changes in speed or age) these data confirm the hypothesis that an increase in C contributes to the decrease in swimming performance that occurs with age. [ABSTRACT FROM AUTHOR]

\ackground: The age of peak swim performance has been investigated for freestyle swimmers for distances ranging from 50 m to 1500 m among swimmers aged 19 to 99 years. However, studies have yet to investigate the 10 to 19 year-old age group. The aims of the present study were (1) to investigate the age range of peak freestyle swim speed, and (2) to find differences in age range and peak freestyle swim speed between male and female freestyle swimmers from 50 m to 1500 m at a national level. Methods: The changes in age range and peak freestyle swim speed among Swiss elite freestyle swimmers aged 0-9 years and 70-79 years who were ranked on the Swiss high score list between 2006 and 2010 were analyzed using linear regression analyses and analysis of variance. Results: Men were fastest at ages 22-23 years for 100 m and 200 m; at ages 24-25 years for 400 m and 800 m; and at 26-27 years for 50 m and 1500 m. Women achieved peak freestyle swim speed at ages 20-21 years for all distances with the exception of 800 m. In the 800 m, women were fastest at ages 26-27 years. The difference in peak freestyle swim speed decreased with increasing swim distance from 50 m to 800 m (ie, 13.1% ± 1.3% in 50 m; 13.2% ± 0.9% in 100 m; 10.8% ± 0.9% in 200 m; 7.9% ± 1.3% in 400 m; and 4.2% ± 2.0% in 800 m). For 1500 m, however, the gender difference increased to 6.4% ± 2.3%. Conclusion: These findings suggest that peak freestyle swim speed is achieved at lower age ranges in women when compared to men at 50 m to 1500 m, but not at 800 m. The gender difference in peak freestyle swim speed decreased with increasing swim distance from 50 m to 800 m, but not for 1500 m. These data should be confirmed with swimmers at an international level. [ABSTRACT FROM AUTHOR]

Background: Improvement in swimming performance involves the dynamic alignment of the body in liquid, technical skill, anthropometric characteristics of athletes, and the ability to develop propulsive force. The aim of this study was to assess the relationships between the propulsive force during swimming and arm muscle area (AMA) and propose an equation to estimate the propulsive force in young swimmers by measuring their AMA. Methods: Study participants were 28 male swimmers (14 ± 1.28 years) registered in the Brazilian Federation of Aquatic Sports. Their AMA was estimated by anthropometry and skinfold measurement, and the propulsive force of their arm (PFA) was assessed by the tied swimming test. The Durbin-Watson (DW) test was used to verify residual independence between variables (PFA and AMA). A Pearson correlation investigated potential associations between the variables and then a linear regression analysis was established. The Bland-Altman method was used to compare the values found between PFA and propulsive force-estimated (PFE). A paired Student's t-test was used to analyze the difference in PFE with and without the constant and the coefficient of variation (CV) to estimate the magnitude of a real change between these forces. Results: There was a significant positive correlation between the variables AMA and PFA (r = 0.68, P <0.001). The linear regression showed a value of R2 = 0.470. There were no significant differences when comparing PFA and PFE (95% confidence interval: -8.903 to 9.560 kgf). To verify if there was a correlation between these variables, a new linear regression analysis found a value of R2 = 0.668, which confirms an equivalence between PFA and PFE, as CV showed 4% of magnitude. Conclusion: The results of this study suggest the existence of a relationship between levels of PFA and muscle mass, however, this relationship becomes more evident the longer the AMA, which allows the development of an equation to estimate the propulsive force of young swimmers. [ABSTRACT FROM AUTHOR]

The research is conducted on a sample of 39 male, top swimmers, participants in the discipline male 100 meters freestyle stroke swimming, the swimming competitions of the Olympic games held in Sydney in 2000, on which are 11 relevant biomechanical variables were applied, studied and recorded toward the swimmers. The applied regression analysis determined the impact biomechanical variables presented as predictorial on variables parameter, which is the final result (FRES). By applying factor analysis, it has been shown that the structure of the biomechanical variables in the latent space and the extracted factors are presented as a system of predictorial variables. Applied regression analysis has determined the impact of variables parameters. Based on the analysis of the obtained results, which were treated as expected that both isolated varimaks factors have statistically significant partial affect on the outcome toward the criterion result, which were: the specific speed and agility factor and the second was extracted factor response, the frequency, amplitude and efficiency of the strokes. [ABSTRACT FROM AUTHOR]

Copyright of Facta Universitatis: Series Physical Education & Sport is the property of Facta Universitatis, Series Physical Education & Sport and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Purpose. The aim of this study was to analyze selected kinematics parameters of standard front crawl swimming technique and its variants, the 'kayaking' and 'loping', in order to estimate the differences that can determine swimming effectiveness and efficiency Methods. Eighteen swimmers, divided equally into three groups, took part in the research. The first group was composed of individuals who favored the standard technique, the second group used the 'kayaking' variant and the third one swam in the 'loping' variant. All swimmers were instructed to swim the 50 m freestyle with their technique of choice at maximum velocity. Analysis of kinematic parameters (time, average swimming velocity), swimming cycle parameters (stroke length, stroke rate), and the swimming efficiency coefficient (stroke index) was calculated using SIMI's 2D Reality Motion Systems software. Results. The Kruskal-Wallis test and Mann-Whitney U test found statistically significant differences in the studied parameters between the standard technique (S) and the 'kayaking' (K) and 'loping' (L) variants in the time to swim 25 m ( S = 15.472 s, K = 13.540 s, L = 14.108 s), and between (S) and (K) in the 15 m swim time ( St = 9.598 s, Kt = 8.593 s) and average swimming velocity ( Sv = 1.562 m/s, Kv = 1.757 m/s). Conclusions. Analysis of the differences in the kinematic parameters that define front crawl swimming technique finds justification in the need to modify the standard technique of the propulsive movement used in swimming towards those that employ the 'kayaking' and 'loping' variants as they are more effective in affecting swimming velocity. [ABSTRACT FROM AUTHOR]

Background: The aim of this study was to determine differences in stroke length and swimming time over a distance of 25m in a control and an experimental group from the provision of immediate verbal feedback. Material/Methods: The study involved 10 people practicing swimming. They were divided into an experimental and a control group. The subjects performed four trials, swimming the front crawl technique at the distance of 25 meters with a maximum speed. A specially designed research tool enabled the swimmers to obtain immediate verbal feedback during the test. In the control group no immediate verbal feedback was provided. In the experimental group the immediate verbal feedback was provided for the whole duration of swimming. Results: In the experimental group the average swimming stroke length with the front crawl technique has increased by 2.63% and the average swimming time decreased by 4.34% through the provision of immediate verbal feedback. Conclusions: In the experimental group, which obtained immediate verbal feedback, an increase in the average stroke length and a reduction in the average swimming time at the distance of 25m were observed. [ABSTRACT FROM AUTHOR]

Copyright of Apunts: Educació Física i Esports is the property of Institut Nacional d'Educacio Fisica de Catalunya and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

This study was conducted to determine the effect of warm-up on high-intensity front crawl tethered swimming and thus to better understand possible variations in the force exerted by the swimmers. Ten male national level swimmers (mean ± SD; age 15.3 ± 0.95 years old, height: 1.73 ± 5.2 m, body mass: 64.3 ± 7.8 kg, Fat mass 8.31 ± 3.1 kg) participated in this study. After a typical competition warm-up, the subjects performed a 30 s tethered swimming all-out effort in front crawl swimming technique. The same test was repeated in the day after but performed without warming up. Capillary blood lactate concentration was assessed before and after the swimming test and the Borg ratings of perceived exertion scale was used. Without a previous warm-up, the mean ± SD values of maximum and mean forces were 299.62 ± 77.56 N and 91.65 ± 14.70 N, respectively. These values were different (p<0.05) from the values obtained with warm-up (351.33 ± 81.85 N and 103.97 ± 19.11 N). Differences were also observed when regarding to the forces relative to body mass. However, the values of lactate net concentrations after the test performed with and without warm-up were not different (6.27 ± 2.36 mmol⋅l-1 and 6.18 ± 2.353 mmol⋅l-1) and the same occurs with the values of ratings of perceived exertion (15.90 ± 2.42 and 15.60 ± 2.27). These results suggest an improvement of the maximum and mean force of the swimmer on the tethered swimming due to previous warm-up. [ABSTRACT FROM AUTHOR]

The main aim of the present study was to analyze the relationships between dry land strength and power measurements with swimming performance. Ten male national level swimmers (age: 14.9 ± 0.74 years, body mass: 60.0 ± 6.26 kg, height: 171.9 ± 6.26, 100 m long course front crawl performance: 59.9 ± 1.87 s) volunteered as subjects. Height and Work were estimated for CMJ. Mean power in the propulsive phase was assessed for squat, bench press (concentric phase) and lat pull down back. Mean force production was evaluated through 30 s maximal effort tethered swimming in front crawl using whole body, arms only and legs only. Swimming velocity was calculated from a maximal bout of 50 m front crawl. Height of CMJ did not correlate with any of the studied variables. There were positive and moderate-strong associations between the work during CMJ and mean propulsive power in squat with tethered forces during whole body and legs only swimming. Mean propulsive power of bench press and lat pull down presented positive and moderate-strong relationships with mean force production in whole body and arms only. Swimming performance is related with mean power of lat pull down back. So, lat pull down back is the most related dry land test with swimming performance; bench press with force production in water arms only; and work during CMJ with tethered forces legs only. [ABSTRACT FROM AUTHOR]

The article presents a study on added resistance and velocity's effects on national-level swimmers' stroke, coordination, and force parameters in the front crawl swimming technique. A comparison of free-swimming and parachute swimming conditions which were calculated at five velocities per condition are discussed. Free-swimmers adapted to velocity changes by modifying their stroke and coordination. The parachute swimmers enhanced force parameters with propulsive action.

The article discusses a study which found inspiratory muscle fatigue (IMF) significantly impacts breathing frequency, stroke rate, and stroke length in collegiate swimmers during a 200-meter front-crawl swimming session. Data indicates the increase in total breaths taken and number of breaths per minute during IMF is related to alleviating breathlessness or dyspnea.

The article examines the role of strength training (ST) methods in enhancing endurance performance with particular focus on triathlon performance. The claim that ST and endurance training are opposing forms of exercise is tackled. The effects of ST on physiological determinants of triathlon performance which include lactate threshold, anaerobic capacity and neuromuscular qualities are discussed. Also discussed are the effects of ST on injury prevention and freestyle swimming performance.

This study investigated the effect of different sizes of hand paddles on bilateral propulsive force difference (BFD) in the crawl stroke. Fourteen male swimmers (Age: 20.0 ± 3.7 years, 100-m best time: 53.70 ± 0.87 s) were submitted to the following test protocol: 2 × 10 s maximal efforts in the fully tethered swimming, repeated in five conditions: free swimming (FREE), with small (PP, 280 cm2), medium (PM, 352 cm2), large (PG, 462 cm2) and extra-large paddles (PGG, 552 cm2). Stronger (STR) and weaker (WKR) strokes were those which presented the higher and lower mean peak force values in four non-consecutive strokes, respectively. BFD was expressed by the percentage difference between STR and WKR. STR and WKR were significantly different in all the conditions (FREE: 296 × 249 N; PP: 310 × 264 N; PM: 323 × 285 N; PG: 339 × 298 N; PGG: 353 × 310 N). No specific paddle size changed BFD significantly. A significant reduction occurred when the lower individual values of BFD obtained with hand paddles, independently of their size, were compared to those found in FREE (14.9% × 7.4%). The present results showed that the artificial enlargement of hands can acutely reduce the bilateral force difference in competitive swimmers. However, the best size of paddles should be individually chosen. [ABSTRACT FROM AUTHOR]