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Purpose: This study aimed to investigate the effects of a 5-week training cessation on the cardiac autonomic response after a 50-m swimming time-trial test. Methods: Twenty trained and highly trained adolescent swimmers (17.1 [2.7] y) performed a 50-m front-crawl all-out test before (visit 1) and after a 5-week training cessation (visit 2). After the warm-up, heart-rate variability (HRV) was recorded in a seated position using a Polar RS800CX heart-rate monitor during the 10 minutes before (preexercise) and immediately after the 50-m front-crawl all-out test (postexercise). Two-way analysis of variance (time × visit) and analysis of covariance were conducted to compute the effect of the 50-m all-out test on vagal-related HRV parameters (mean R-R, standard deviation of R-R intervals [SDNN], square root of the mean squared differences between successive R-R intervals [RMSSD], the percentage number of pairs of adjacent normal R-R intervals differing by more than 50 milliseconds in the entire recording [pNN50], and power in the high frequency [HF]) with Bonferroni post hoc test. Results: All the HRV parameters had a time main effect (P P P P P P Conclusions: After 5 weeks of training cessation, all the preexercise and postexercise vagal-related HRV parameters evidenced a reduction, suggesting an impairment in swimmers’ physical status. Coaches should be cautious with training loads at the start of the season.

This systematic review aims to summarize the effects of wearing different types of wetsuits and swimsuits in front crawl swimming performance and physiological- and biomechanical-related variables. The Web of Science, PubMed, Scopus and the Proceedings of the International Symposium on Biomechanics and Medicine in Swimming databases were searched from inception to 25th March 2022. From the 1398 studies initially found, 26 studies were included in the review. The quality assessment and inter-rater reliability between researchers were conducted. The full body was the most studied wetsuit, with its use allowing 3.2–12.9% velocity increments in distances ranging from 25 to 1500 m, in incremental tests, in 5 and 30 min continuous swimming and in open water events. The sleeveless long vs. the full-body wetsuit led to a 400–800 m performance enhancement. Higher stroke rate, stroke length and stroke index were observed while using three different covered body part wetsuits vs. a regular swimsuit, with a lower energy cost being observed when swimming with the full-body wetsuit compared to a swimsuit. These findings provide useful information for coaches, swimmers and triathletes about the full-body and sleeveless long/short wetsuit use, since these three wetsuits allow improving swimming performance in different distances in diverse aquatic environments.

Our aim was to establish the determinants explaining the wetsuit advantages in middle-distance swimming efforts. Thirty-one triathletes and open water swimmers performed two 400 m front crawl bouts in a 25 m swimming pool with swim and wetsuits (with 48 h rest in-between). Anthropometric, kinematic and physiological variables were measured and Pearson correlation coefficients and stepwise linear regression analysis were used to determine their relationships. Associations observed in the 400 m front crawl included time improved using wetsuit with swimmers age (r=0.38; p=0.017), cross-sectional area (r=0.33; p=0.034), wetsuit upper limbs thickness (r=–0.49; p=0.010), ΔInternational Swimming Federation Points (r=–0.39;p=0.016), Δstroke rate (SR, r=0.48; p=0.003), Δstroke length (SL, r=-0.39; p=0.015), Δpropelling efficiency (r=–0.37; p=0.019) and Δblood lactate concentrations (r=0.30; p=0.048) in the total sample. In females, associations were found between the time improved and wetsuit upper and lower limbs thickness (both r=–0.78; p=0.011), and in males associations were found between time improved and age (r=0.43; p=0.030), ΔSR (r=0.56; p=0.005) and ΔSL (r=–0.44; p=0.026). Furthermore, 48% of the 400 m front crawl time improved was explained by wetsuit upper limbs thickness and SR changes (total sample), 62% explained by the wetsuit lower limbs thickness (females) and 48% of this enhancement was related to age and SR changes (males). Therefore, faster upper and lower limbs actions and wetsuit upper and lower limbs thickness are beneficial for 400 m front crawl performance improvement.

Purpose: To assess changes in swimming performance, anthropometrics, kinematics, energetics, and strength after 5-week training cessation. Methods: Twenty-one trained and highly trained swimmers (13 males: 17.4 [3.1] y; 50-m front crawl 463 [77] FINA points; 8 females: 16.7 [1.7] y; 50-m front crawl 535 [48] FINA points) performed a 50-m front-crawl all-out swim test, dryland and pool-based strength tests, and 10-, 15-, 20-, and 25-m front-crawl all-out efforts for anaerobic critical velocity assessment before and after a 5-week training cessation. Heart rate and oxygen uptake () were continuously measured before and after the 50-m swim test (off-kinetics). Results: Performance was impaired 1.9% (0.54 s) for males (P = .007, d = 0.91) and 2.9% (0.89 s) for females (P = .033, d = 0.93). Neither the anthropometrical changes (males: r2 = .516, P = .077; females: r2 = .096, P = .930) nor the physical activities that each participant performed during the off-season (males: r2 = .060, P = .900; females: r2 = .250, P = .734) attenuated performance impairments. Stroke rate and clean swimming speed decreased (P P > .05). Blood lactate concentrations remained similar (P > .05), but peak decreased in females (P = .04, d = 0.85). Both sexes showed higher heart rate before and after the 50-m swim test after 5 weeks (P P = .035, d = 0.65). Lower in-water force during tethered swimming at zero speed was observed in males (P = .033, d = 0.69). Regarding dryland strength, lower-body impairments were observed for males, while females showed upper-body impairments (P Conclusions: A 5-week training cessation yielded higher heart rate in the 50-m front crawl, anaerobic pathways, and dryland strength impairments. Coaches should find alternatives to minimize detraining effects during the off-season.

The effects of pre-activation exercises on undulatory underwater swimming (UUS) have not been studied. This research aimed to: 1) assess the effects of a jumping-exercise strategy upon UUS performance and kinematics variables; 2) test the different effects on males and females, and; 3) to explore if stronger participants exhibit greater post-activation performance enhancement (PAPE). Ninety-two age-group national level swimmers randomly assigned into control (17 males and 18 females) and experimental groups (27 males and 30 females) took part in a cross-sectional study designed to test two maximal 15-m UUS performance efforts. The experimental group performed four maximal tuck jumps before the first or the second UUS effort. Performance and kinematics variables were analyzed using instantaneous velocity data via speedometer. Maximal lower-limbs force was obtained during a countermovement jump through a linear-encoder. Two-way repeated measures ANOVA test and linear regression analysis were used to explore variable interactions between baseline and PAPE, and the association between the PAPE response and strength of the swimmers, respectively. Despite trends toward improvements in push-off velocity (Δ = 1.33%; d = 0.12), the results did not show enhancements nor deterioration in UUS performance and kinematics after the tuck jumps. No specific PAPE responses modulated by sex or by the strength level of the swimmers were observed for this age-group (p < 0.05). Four tuck jump repetitions executed prior to diving could be insufficient to acutely enhance UUS performance. The fact that the exercise performed during warm-up was a body-weight based exercise, was possibly not enough to evoke PAPE.

Funding: This study was supported by grants awarded by the Ministry of Economy, Industry and Competitiveness (Spanish Agency of Research) and the European Regional Development Fund (ERDF); DEP2014-59707-P “SWIM: Specific Water Innovative Measurements applied to the development of International Swimmers in Short Swimming Events (50 and 100 m), by the Ministry of Science, Innovation and Universities (Spanish Agency of Research) and the European Regional Development Fund (ERDF); PGC2018-102116-B-I00 “SWIM II: Specific Water Innovative 10 J. J. RUIZ-NAVARRO ET AL. Measurements: Applied to the performance improvement” and the Spanish Ministry of Education, Culture and Sport: FPU17/02761 grant. This article is a part of an international thesis belonging to the Program of PhD in Biomedicine (B11.56.1), from the University of Granada, Granada (Spain). This study aimed 1) to examine variables that may quantify the ability to apply force in the water and 2) to test their relationship with free swimming performance. Sixteen regional-level swimmers participated in this study. Average (Favg) and maximum (Fmax) forces were measured for 30 s arm stroke tethered swimming in a flume at zero and 1.389 m/s water flow speeds. The maximum and average force’s relative changes (ΔFmax and ΔFavg, respectively) were calcu-lated between tethered swimming at zero and 1.389 m/s water flow speeds. Free swimming speeds were obtained from 25, 50, and 100 m front crawl trials, and were correlated with ΔFmax and ΔFavg. A negative correlation was found between ΔFmax and 25, 50 and 100 m speeds (r = -0.84, r = -0.74, r = -0.55; p < 0.05, respectively) and ΔFavg correlated negatively with 25 and 50 m speeds (r = -0.63, r = -0.54; p < 0.05, respectively), but it did not correlate with 100 m swimming speed. The relative change in force could be used to quantify the ability to apply force in the water. This could aid coaches to understand if changes in swimmers’ ability to apply force in the water contribute to improvements in performance. info:eu-repo/semantics/publishedVersion

Cuenca-Fernández, F, Ruiz-Teba, A, López-Contreras, G, and Arellano, R. Effects of 2 types of activation protocols based on postactivation potentiation on 50-m freestyle performance. J Strength Cond Res 34(11): 3284-3292, 2020-Postactivation potentiation (PAP) is a phenomenon which improves muscle contractility, strength, and speed in sporting performances through previously applied maximal or submaximal loads on the muscle system. This study aimed to assess the effects of 2 types of activation protocols based on PAP, on sprint swimming performance. A repeated-measures design was used to compare 3 different scenarios before a 50-m race. First, all of the participants performed a standard warm-up (SWU), consisting of a 400-m swim followed by dynamic stretching. This protocol acted as the control. Subsequently, the swimmers were randomly assigned into 2 groups: the swimmers in the first group performed the SWU followed by a PAP one-repetition maximum warm-up (RMWU), consisting of 3 "lunge" and 3 "arm stroke" repetitions, both at 85% of the one-repetition maximum. The swimmers in the second group performed the SWU followed by a PAP eccentric flywheel warm-up (EWU), consisting of one set of 4 repetitions of exercises of both the lower and upper limbs on an adapted eccentric flywheel at the maximal voluntary contraction. The time required for the swimmers to swim 5 and 10 m was shorter with the PAP protocols. The swimming velocity of the swimmers who underwent the EWU and RMWU protocols was faster at 5 and 10 m. The best total swimming time was not influenced by any of the protocols. When isolating swimming (excluding start performance and turn), best time was achieved with the SWU and RMWU compared with EWU (SWU: 20.86 ± 0.95 seconds; EWU: 21.25 ± 1.12 seconds; RMWU: 20.97 ± 1.22 seconds). In conclusion, a warm-up based on PAP protocols might exert an influence on performance in the first meters of a 50-m race. Nevertheless, other factors, such as fatigue, could modify swimming patterns and yield results contradictory to those of the desired task.

Applying maximum conditioning exercises temporarily improves muscle contractility thanks to post-activation performance enhancement (PAPE). However, it is now known whether the system can improve its adaptability to the procedure through a training based on the conditioning exercises themselves. This study set out to test a PAPE protocol in 14 swimmers before and after a training period. Initially, the subjects’ strength in both the lower and upper extremities was tested. Subsequently, the effects of two types of warm-ups were tested in a 50-metre swimming test, one a standard warm-up and the other one a PAPE which included maximum repetitions executed on eccentric training machines. A 6-week training protocol was then applied (2 days/week), in which maximum repetitions were executed on eccentric training machines, and the effects were once again studied both on the strength tests and after both warm-ups. The performance improved at 15 metres after the PAPE compared to the standard situation, but not in the subsequent metre marks. After the 6 weeks, increases in strength in the lower extremities (14.46%) and upper extremities (12.4%) were recorded. Following the application of the PAPE warm-up, the starting speed increased and swimming time and speed improved at 25, 40 and 50 metres, which suggests that the subjects were capable of attaining a better balance between fatigue and potentiation., CTS-527: Actividad física y deportiva en el medio acuático

Purpose: To observe changes in performance, physiological, and general kinematic variables induced by the use of wetsuits vs swimsuits in both swimming-pool and swimming-flume conditions. Methods: In a randomized and counterbalanced order, 33 swimmers (26.46 [11.72] y old) performed 2 × 400-m maximal front crawl in a 25-m swimming pool (with wetsuit and swimsuit), and their mean velocities were used later in 2 swimming-flume trials with both suits. Velocity, blood lactate concentration, heart rate (HR), Borg scale (rating of perceived exertion), stroke rate, stroke length (SL), stroke index, and propelling efficiency were evaluated. Results: The 400-m performance in the swimming pool was 0.07 m·s−1 faster when using the wetsuit than when using the swimsuit, evidencing a reduction of ∼6% in time elapsed (P Conclusions: The 6% velocity improvement was the result of an increase of 4% in SL. Swimmers reduced stroke rate and increased SL to benefit from the hydrodynamic reduction of the wetsuit and increase their swimming efficiency. Wetsuits might be utilized during training seasons to improve adaptations while swimming.

This study aimed to compare three swimming conditions in a swimming flume with water at 26 ℃ (using swimsuit) and 18 ℃ (randomly with swimsuit and wetsuit). Seventeen swimmers (32.4±14.7 years old, 175.6±0.06 cm height, and 70.4±9.8 kg body mass) performed three bouts until exhaustion at a 400-m front crawl pace (24 h intervals). ANOVA repeated measures compared the experimental conditions. Swimming at 26 ℃ with swimsuit evidenced a higher metabolic demand (total energy expenditure; (E)), comparing to 18 ℃ swimsuit (p=0.05) and with 18 ℃ wetsuit (p=0.04). The 26 ℃ swimsuit condition presented higher peak oxygen uptake (VO2peak), blood lactate concentrations ([La-]peak), rate of perceived exertion (RPE), maximal heart rate (HRmax), anaerobic lactic energy (AnL), E, energy cost (C), VO2 amplitude (Ap), and stroke rate (SR), but lower stroke length (SL) and stroke index (SI) than 18 ℃ wetsuit. The 18 ℃ swimsuit condition (comparing to wetsuit) lead to higher VO2peak, [La-]peak, HRmax, E, C, Ap, and SR but lower SL and SI. Swimming at aerobic power intensity with swim and wetsuit at 18 ℃ does not induce physiologic and biomechanical disadvantages compared to 26 ℃. The results suggested that the use of wetsuit might increase performance at 18 ℃ water temperature for competitive master swimmers. Its use is thus recommended in open water swimming competitions when the water temperature is 18–20 ℃.

In swimming, the underwater phase after the start and turn comprises gliding and dolphin kicking, with the latter also known as underwater undulatory swimming (UUS). Swimming performance is highly dependent on the underwater phase; therefore, understanding the training effects in UUS and underwater gliding can be critical for swimmers and coaches. Further, the development of technique in young swimmers can lead to exponential benefits in an athlete's career. This study aimed to evaluate the effects of a training protocol on UUS and underwater gliding performance and kinematics in young swimmers. Seventeen age group swimmers (boys = 10, girls = 7) performed maximal UUS and underwater gliding efforts before and after a seven-week training protocol. Time to reach 10 m; intra-cyclic mean, peak, and minimum velocities; and gliding performance improved significantly after the training protocol. The UUS performance improvement was mostly produced by an improvement of the upbeat execution, together with a likely reduction of swimmers' hydrodynamic drag. Despite the changes in UUS and gliding, performance was also likely influenced by growth. The findings from this study highlight kinematic variables that can be used to understand and quantify changes in UUS and gliding performance. ispartof: SPORTS BIOMECHANICS ispartof: location:England status: published

The aim was to analyse the influence of the breaststroke underwater phase on 50 and 100 m performance. A total of 108 performances in 50 m (61 males and 47 females), and 126 performances in 100 m (71 males and 55 females) were recorded during the 2019 Short-course National Spanish Championship. The underwater swimming time, distance and velocity were analysed after the start and turns. Pearson correlation coefficients (r) and regression analysis were applied to compute the relation between the variables. The relative contribution (%) to final time and the differences between events and gender were studied through independent samples t-test (p < 0.05). High correlations were obtained for both events and genders between start time and final time (r = 0.76–0.91). The emersion velocity was higher in 50 m than in 100 m (p < 0.001; d > 1.0) and in males (50 m: 2.18 ± 0.10 m·s−1; 100 m: 1.87 ± 0.08 m·s−1) than in females (50 m: 1.92 ± 0.09 m·s−1: 100 m: 1.71 ± 0.08 m·s−1). Performance in both events was influenced significantly by turn velocity (r ≥ −0.85), and combined with the start, contributed to around 55% of the final time. Coaches should optimise the underwater phases of start and turns on breaststroke performance in short-course., This study was supported by grants awarded by the Ministry of Innovation and Universities (Spanish Agency of Research) and the European Regional Development Funds (ERDF); PGC2018-102116, B-100 “SWIM II: Specific Water Innovative Measurements: Applied to the Performance Improvement”

Underwater undulatory swimming (UUS) influences overall swimming performance, therefore swimmers should try to maximize it. This research aimed to: 1) assess the effects of an activation protocol based on post-activation performance enhancements upon UUS; and 2) evaluate the differences between males and females. Seventeen competitive swimmers (male = 10; female = 7) participated in a cross-sectional study designed to test performance in UUS at 10 m after a traditional swimming warm-up (TRA) and after adding to the TRA 4 maximal half-squat repetitions on an inertial flywheel device (PAPE). A speedometer and an electronic timing system were used to obtain kinematic variables such as time, frequency and velocity at 10-m, which were processed with MATLAB®. A paired sample t test was applied to determine the differences of the kinematic variables between the TRA and PAPE. An independent sample t test was used to determine the effects of the PAPE in males and females. Participants reduced the time to cover 10 m after PAPE compared to the TRA (males: 5.77 ± 0.44 to 5.64 ± 0.46; females 6.34 ± 0.80 to 6.09 ± 0.66; p < 0.05). In addition, trends towards improvements in UUS velocity were obtained for males and females. However, push-off velocity and frequency showed a different tendency between genders (p < 0.05). In conclusion, the warm-up including repetitions on the flywheel device improved UUS performance. Some differences were obtained between genders after PAPE. Further research should confirm if the benefits obtained after the eccentric overload would depend either on gender or on other components such as fiber type composition.

The study was supported and funded by the Faculty of Faculty of Psychology, Education Sciences and Sport Blanquerna, Ramon Llull University, Barcelona, Spain, grant number PIF1920-PSITIC, Background/objectives: The potential advantages of wearing customized bite-aligning mouthguards on several performance parameters such as muscular strength, power and reaction time have been reported. Literature shows that the concurrent activation potentiation phenomenon, elicited by a powered and balanced jaw clenching, can provide athletes with several neuromuscular advantages. The aim of the present study was to investigate the acute effects of jaw clenching while wearing a customized bitealigning mouthguard on swimming start, countermovement jump and swim bench test, in contrast to two other conditions: non-jaw clenching and jaw clenching without mouthguard. Methods: A randomized, repeated measure within study designwas used to compare the condition effect on eight highly trained elite male and female swimmers. Results: Statistical analysis revealed a significant increase in the countermovement jump height (p ¼ 0.041) when comparing the use of mouthguards with the non-jaw condition. In the swim bench, a significant greater time to peak force (p ¼ 0.049) was found when comparing the use of mouthguards with the jaw condition. Although, non-significant effects, small differences were found in the start reaction time and 15-m freestyle swimming when comparing the use of mouthguards with the non-jaw condition. Conclusion: This study demonstrated that wearing customized, bite-aligning mouthguards had an ergogenic effect on specific measures of vertical jump and swim bench test, whereas non-meaningful but small differences were found in swimming start., Faculty of Faculty of Psychology, Education Sciences and Sport Blanquerna, Ramon Llull University, Barcelona, Spain PIF1920-PSITIC

Swimming analysts aid coaches and athletes in the decision-making by providing evidence-based recommendations. The aim of this narrative review was to report the best practices of swimming analysts that have been supporting high-performance athletes. It also aims to share how swimming analysts can translate applied research into practice. The role of the swimming analyst, as part of a holistic team supporting high-performance athletes, has been expanding and is needed to be distinguished from the job scope of a swimming researcher. As testing can be time-consuming, analysts must decide what to test and when to conduct the evaluation sessions. Swimming analysts engage in the modelling and forecast of the performance, that in short- and mid-term can help set races target-times, and in the long-term provide insights on talent and career development. Races can be analysed by manual, semi-automatic or fully automatic video analysis with single or multi-cameras set-ups. The qualitative and quantitative analyses of the swim strokes, start, turns, and finish are also part of the analyst job scope and associated with race performance goals. Land-based training is another task that can be assigned to analysts and aims to enhance the performance, prevent musculoskeletal injuries and monitor its risk factors. This project was funded by the FCT - Portuguese Foundation for Science and Technology (UIDB/DTP/04045/2020). info:eu-repo/semantics/publishedVersion

BACKGROUNDː The swimming community has shown considerable interest in using dry-land warm-ups as a method of impacting performance. This study compared the effects of high-resistance pull-over and swimming warm-up in semi-tethered resisted swimming. METHODSː An incremental-load semi-tethered swimming test was individually administered in 20 national-competitive swimmers to determine the load maximizing swimming power. In different sessions, participants tested such a load 6 min after a swimming warm-up (SWU) or a dry-land warm-up (DLWU: 3 pull-over reps at 85% of the one-repetition maximum). Kinetic variables (velocity, force, acceleration, impulse, power rate of force development (RFD) and intra-cycle variation), were obtained with a linear encoder through trapezoidal integration regarding time. Kinematic variables (distance, time, stroke-rate and stroke-length), were obtained by video recordings. The differences between protocols were observed by paired-samples T-test (ANOVA). Pearson’s coefficient explored correlations between kinetics and kinematics variables; significance was set at P

This study was supported by grant awarded by the Ministry of Economy, Industry and Competitiveness (Spanish Agency of Research) and the European Regional Development Fund (ERDF); DEP2014-59707-P “SWIM: Specific Water Innovative Measurements” applied to the devel- opment of International Swimmers in Short Swimming Events (50 and 100 m) and the Spanish Ministry of Education, Culture and Sport: FPU17/ 02761 grant. This article is a part of an international thesis belonging to the Program of PhD in Biomedicine (B11.56.1), from the University of Granada, Granada (Spain)., Español: Esta investigación tuvo como objetivo estudiar la relación entre la fuerza en nado atado en una piscina contracorriente a diferentes velocidades de flujo con el rendimiento de nado en pruebas de velocidad. Los resultados obtenidos señalan que la asociación de la fuerza medida es mayor con el rendimiento cuanto mayor es la velocidad de flujo. Esto permite la evaluación de la habilidad para aplicar fuerza de forma efectiva en el agua, English: This research aimed to study the relationship between tethered swimming in a flume at different speeds and swimming performance. Measuring force in a swimming flume at higher velocities is a better indicator of performance than stationary tethered swimming. It allows assessing the ability to effectively apply force in the water, Departamento de educación física y deportiva

Objetivo Este estudio experimentó un protocolo de post-activación potenciación estimulada en 16 nadadores de competición. Método En primer lugar, se aplicaron ejercicios de acondicionamiento para extremidades superiores e inferiores y se exploraron los efectos producidos tras 5, 8, 12 y 20 minutos de descanso en un test que implicaba 3 saltos verticales y 3 flexiones explosivas. En una sesión posterior, se aplicaron ejercicios de acondicionamiento específico en ambas extremidades proporcionando el mismo tiempo de descanso que había inducido los mejores resultados en la evaluación exploratoria (8 min), y sus efectos se evaluaron en una prueba de natación sprint (50-m). Finalmente, también se obtuvo el índice de fuerza relativa de los participantes y se estudió su relación con el rendimiento. Resultados Las variables relacionadas con la salida de natación mejoraron. La velocidad en el despegue fue mayor debido al incremento de las fuerzas desarrolladas en el poyete. El tiempo de nado en la prueba de 50-m se mantuvo igual a la situación estándar aunque la velocidad fue mayor en los primeros metros. Conclusiones: Los sujetos con mayor índice de fuerza obtuvieron mejores resultados y reaccionaron mejor a la post-activación potenciación estimulada posiblemente porque sus efectos son más efectivos en las fibras tipo II y estas, son más comunes en sujetos entrenados., CTS-527: Actividad física y deportiva en el medio acuático

Context: In front-crawl swimming, the upper limbs perform alternating movements with the aim of achieving a continuous application of force in the water, leading to lower intracyclic velocity variation (dv). This parameter has been identified as a crucial criterion for swimmers’ evaluation. Purpose: To examine the assessment of intracyclic force variation (dF) and to analyze its relationship with dv and swimming performance. Methods: A total of 22 high-level male swimmers performed a maximal-effort 50-m front-crawl time trial and a 30-s maximal-effort fully tethered swimming test, which were randomly assigned. Instantaneous velocity was obtained by a speedometer and force by a strain-gauge system. Results: Similarity was observed between the tests, with dF attaining much higher magnitudes than dv (P d = 8.89). There were no differences in stroke rate or in physiological responses between tethered and free swimming, with a high level of agreement for the stroke rate and blood lactate increase. Swimming velocity presented a strong negative linear relationship with dF (r = −.826, P dv (r = .734, P dF, multiple-regression analysis explained 83% of the free-swimming performance. Conclusions: Assessing dF is a promising approach for evaluating a swimmer’s performance. From the experiments, this new parameter showed that swimmers with higher dF also present higher dv, leading to a decrease in performance.

The purpose of this study was to investigate the association between race-start wall contact time and final performance for each sex as a function of classification and anti-slip start-device use (with or without) in backstroke events of international competitions. Twenty-one international competitions covering a 10-year period (2006–2015) were analysed, retrospectively. The data corresponded to the competition histories of 1723 swimmers. For the contact-time data of each event (50-m, 100-m and 200-m), two-way ANOVAs (sex × classification and sex × start device use) were performed. The Bonferroni post-hoc test was used to compare means, and Pearson’s simple correlation coefficient to determine possible correlations between wall contact times and final performance. The results showed the men to have shorter wall contact times than the women in the 50-m and 100-m events, and that, for the women medallists, their wall contact times were positively correlated with final performance in all events excep...

The purpose of this study was two-fold: to define the characteristics and to analyse the advantages of the last changes produced in the swimming starts as a consequence of the implementation of kick-start; and with the aim to present topics for future studies and guidance for coaches and swimmers. Fifty studies were reviewed: forty-eight related to the grab start, six focused on the track start and studied the kick-start. Nine additional studies are were comparisons between the grab start and track start, six compared the track start and kick-start and just one compared the three start techniques. The outcomes of the studies included in this review showed clear advantages in the kick-start performance with respect to the grab start or track start. The back plate implementation enhanced the force development on the block resulting in larger horizontal take-off velocities and shorter block times. These advantages induced significant improvements in the flight phase with larger distance travelled in less time and shorter time to 5, 10 and 15 m. The use of flexibility training programs as well as lower body strength and power are recommended for an improvement in kick-start technique. For an improvement in kick-start technique is recommended for coaches and swimmers the use of training programs designed to improve the lower body strength and power and the use of flexibility training programs. Resumen. El propósito de esta revisión fue definir las características y analizar las ventajas de los últimos cambios producidos en las salidas de natación debido a la aparición de un nuevo poyete implementado con un apoyo posterior y con el objetivo de presentar temas para futuras investigaciones y una guía para entrenadores y nadadores. Para llevar a cabo dichos objetivos, cincuenta estudios fueron revisados de los cuales cuarenta y ocho analizaron la salida de agarre, seis incluyeron la salida de atletismo y diez la salida de atletismo con apoyo posterior. Además, una comparación entre el rendimiento de la salida de agarre y la salida de atletismo fue llevada a cabo en nueve de los Nueve estudios incluidos en esta revisión más compararon la salida de agarre y la salida de atletismo, seis compararon la salida de atletismo y la salida de atletismo con apoyo posterior y solamente uno incluyó una comparativa entre comparó las tres técnicas. Los resultados de los estudios mostraron claras ventajas en el rendimiento de total la salida desde con los nuevos poyetes con apoyo posterior con en comparación respecto a la salida de agarre o la salida de atletismo. La implementación del apoyo posterior incrementó la fuerza generada en el poyete permitiendo obtener una mayor velocidad horizontal en el despegue y un menor tiempo de poyete. Estas ventajas dieron lugar a una mejoras significativa en la fase de vuelo (tiempo de vuelo y distancia de vuelo) con mayores distancias recorridas en un tiempo más corto y en los tiempos de salida a menores tiempos a los 5, 10 y 15 m. Para la mejora de la salida de atletismo con apoyo posterior se recomienda a entrenadores y nadadores incluir programas de entrenamiento dirigidos a una mejor aplicación de fuerza en el poyete con apoyo posterior la mejora de la fuerza de los miembros inferiores y la potencia así como el uso de programas de flexibilidad.

The aim of this study was to examine the performance characteristics of male and female finalists in the 100-m distance at the 2016 European Championships in swimming (long-course-metre). The performances of all 64 (32-males and 32-females) were analysed (8 swimmers per event; Freestyle, Backstroke, Breaststroke and Butterfly). A set of start and turn parameters were analysed. In the start main outcome, male swimmers were faster in Butterfly (5.71 ± 0.14s) and females in Freestyle (6.68 ± 0.28s). In the turn main outcome, male and female swimmers were faster in Freestyle (males: 9.55 ± 0.13s; females: 10.78 ± 0.28s). A significant and strong stroke effect was noted in the start and turn main outcome, in both sexes. In the start plus the turn combined, males and females were faster in Freestyle (males: 15.40 ± 0.20s; females: 17.45 ± 0.54s). The start and the turn combined accounted almost one-third of the total race time in all events, and non-significant differences (p > 0.05) were noted across the four swim strokes. Once this research made evident the high relevance of start and turns, it is suggested that coaches and swimmers should dedicate an expressive portion of the training perfecting these actions.

This study aimed to assess the effects of post-activation potentiation in the strength related variables of a kick start. Thirteen competitive swimmers performed three kick starts after a standardized warm up (denoted USUAL) and another after inducing post-activation through five isotonic repetitions on an eccentric flywheel (denoted PAP). A T-test was used to quantify differences between USUAL and PAP warm up. The best trial of each subject achieved by natural conditions (denoted PEAK) was compared with data obtained after PAP. An instrumented starting block with independent triaxial force plates, collected the strength variables related with the impulse at take off. Improvements in the vertical components of force were observed after PAP compared with USUAL, meanwhile no differences were detected on the horizontal components of it. The velocity at take off was higher after PAP compared with the USUAL (4.32 ± 0.88 vs 3.93 ± 0.60 m*s-1; p = 0.02). No differences in force or velocity were detected comparing PAP with PEAK (4.13 ± 0.62 m*s-1, p = 0.11). The PAP warm-up increased vertical force and it was transferred to a higher resultant velocity at take-off. This improvement would equal the best result possible obtained in natural conditions after some trials., CTS-527: Actividad física y deportiva en el medio acuático

The aim of this study was to compare sagittal plane lower limb kinematics during walking on land and submerged to the hip in water. Eight healthy adults (age 22.1 ± 1.1 years, body height 174.8 ± 7.1 cm, body mass 63.4 ± 6.2 kg) were asked to cover a distance of 10 m at comfortable speed with controlled step frequency, walking forward or backward. Sagittal plane lower limb kinematics were obtained from three dimensional video analysis to compare spatiotemporal gait parameters and joint angles at selected events using two-way repeated measures ANOVA. Key findings were a reduced walking speed, stride length, step length and a support phase in water, and step length asymmetry was higher compared to the land condition (p

El objetivo del presente artículo ha sido revisar la bibliografía relacionada con las características espacio-temporales y angulares de la marcha en el medio acuático y terrestre. La búsqueda de artículos se realizó en las bases de datos PubMed, MedLine, y Web of Science y revistas científicas específicas. Las palabras claves utilizadas fueron: biomechanical, kinematics, water, land, walking, gait, stride, entre otras. De los 165 resultados obtenidos inicialmente, 20 documentos fueron los seleccionados para nuestra revisión y posterior análisis. Los aspectos de refinado fueron los tipos de documentos, categorías, resúmenes y títulos. Se analizaron todos los artículos en función de sus objetivos, muestra, intervención, variables, resultados y conclusiones. Finalmente, se profundizó y discutió aquellos trabajos científicos que evaluaban los parámetros biomecánicos de la marcha: longitud de ciclo, longitud de paso, frecuencia, duración del ciclo de la marcha, velocidad, ancho de paso, simetría, ángulos y duración de la fase de apoyo.Abstract. The aim of this article was to review the literature on the spatiotemporal and angular characteristics of gait in the aquatic and land environment. The search was performed in databases such as PubMed and Web of Science and scientific journals our specific topic. The key words used were: biomechanics, kinematics, water, land, walking, gait, stride, among others. Of the 165 initial results, 20 papers were selected for our review and subsequent analysis. The aspects of refined were the types of documents, categories, abstracts and titles. All the articles were analyzed in terms of their objectives, sample, intervention, variables, results and conclusions. Finally, we deepened and discussed scientific works that evaluated kinematics parameters of walking: stride length, step length, frequency, stride duration, speed, step width, symmetry, angles and support phase duration.

Fifteen trained athletes were assessed for postactivation performance enhancement (PAPE) of squat jumps (SJ) and power push-ups (PPU) following upper body activation, lower body activation, upper and lower body activation, and rest. SJ improved similarly across all four conditions. PPU could not be assessed. Since the protocol of SJ and PPU involved upper and lower body activation and caused PAPE in SJ, future work is required to determine if a non-localized PAPE effect exists., CTS-527: Actividad física y deportiva en el medio acuático

A low grade mineral composed of 50% kaolinite and 50% quartz was activated with solutions of Na 2 O⋅ r SiO 2 ⋅ x H 2 O. Pastes and mortars with aggregate:binder ratios of 3:1, 5:1 and 7:1 were investigated varying the molar ratios SiO 2 /Al 2 O (2.7–3.3), Na 2 O/Al 2 O 3 (0.7–1.0) and H 2 O/Na 2 O (11–13). The results showed that the compressive strength was reduced by increasing the aggregate:binder ratio, nonetheless, mortars with a ratio 7:1 achieved 30 MPa at 28 days. The curing of mortars at 75° for 24 h favored a rapid development of strength at 1 day, but without a significant increase afterwards at 20 °C. The microstructures of samples cured at 20 °C were dense, while those exposed at 75 °C showed porosity, as well as unreacted particles of quartz, limestone aggregates and metakaolin in a matrix of geopolymeric gel.

The detailed study of the turbulence and the fluid flow in sport is an open and exciting field of research, in particular in swimming and aquatic sports there is a wealth of new techniques that may aid performance. In swimming, thanks to measurement techniques like Particle Image Velocimetry (PIV), Particle Tracking (PT) or pattern analysis, now it is possible to measure the flow environment and not just the human movement. Numerical Computational Fluid Dynamics (CFD) is also a useful tool. We present several techniques stressing the importance of 3D effects and the dynamics of enhanced propulsion by hands and feet while the reduction in resistance need to be considered in an integrated way. Examples of Sculling, Hand wakes, Underwater Undulatory Swimming (UUS) and Vortex Filament Analysis (VFA) are all interesting to improve swimming techniques.

Mechanical power output is a reliable predictor of swim speed in front crawl. However, a complete power curve (power vs. load) has not been described for swimming, and intra-cycle power has not been assessed. The purpose of this study was to examine intra-cycle power output at propulsive phases and to determine maximum swimming power, the corresponding load and swimming speed. 18 swimmers (age 22.10±4.31years, height 1.79±0.07 m, arm span 1.85±0.08 m and body mass 76.74±9.00 kg) performed a swim power test. It consisted of 12.5 m all-out swims with only the arms, with a load attached to the swimmer. A linear encoder and a load cell recorded intra-cycle speed and force in each trial. The test was recorded with 2 underwater cameras. Intra-cycle power was obtained for propulsive stroke phases (pull: 60.32±18.87 W; push: 71.21±21.06 W). Peak power was 114.37±33.16 W. Mean maximum swim power was 66.49 W (0.86 W/kg), which was reached at a swimming velocity of 0.75 m/s with a 47.07% of the individual maximal load. Significant positive correlation (r=0.76, p0.01) between maximum swim power and maximum swim speed was observed. These results suggest that the proposed test may be a training tool that is relatively simple to implement and would provide swimmers and coaches with quick feedback.

INTRODUCTION The article by Melanie Lang and Richard Light provides interesting information related to the difficult task of adapting a swimming training programme to the general guidelines that the sport governing bodies impose to obtain funding support for the competitive programme. In general terms, a long term athlete development (L TAD) model is written by sport experts to define a general pathway of athlete development to achieve national or international performances in dif ferent sports or in a particular sport based on an interdisciplinary scientific knowledge. Numerous such models have been published and distributed for years in many countries and seek to guide the achievement of outstanding performances in many sports (see Canadian and English examples [1, 2]). The programme application entails a considerable ef fort on the part of the participants (swimmers, coaches and clubs), but unfortunately this ef fort seems absolutely necessary to obtain international performances. The problem arises when external guidelines based on LTAD may contradict, in some cases, the competitive rules that should stimulate participation in this long-term programme, as the cited article tries to demonstrate. However, I wish to deal with the conclusion of the article that concerned the impact of excessive volume upon development of technique. This led me to deal with the lack of attention that swimming-planning specialists devote to this highly influential factor in swimming performance.

This investigation statistically examines the strength development on alkaline activation of metakaolin (Mk)/blast furnace slag (BFS) pastes. The main parameters studied are: BFS/Mk weight ratio (100/0, 80/20, 50/50, 20/80, and 0/100), modulus of the alkaline solutions of sodium silicate (M=SiO2/NaO2 at 0, 1, 1.5, 2), %Na2O (5%, 10%, and 15%), and curing time. Cubes were cured at 20°C for up to 360 days; the compressive strength and other characteristics were investigated. A fully factorial experimental design was used to determine the influence of each variable. The curing time and the interaction of the factors BFS/Mk ratio-%Na2O were the most important, followed by the modulus and then the %Na2O; others such as the interaction BFS/Mk ratio modulus were less important. The results indicated that the addition of Mk to BFS reduced the strength, more notably at contents above 50%. For strength development, the most effective modulus was Ms=1 and higher %Na2O were required with higher Mk loads.

The aim of this study was to analyse the mechanics of rotation and the temporal, angular and kinematics variables during the aerial phase for the kick-start with respect to the grab start. Nine elite swimmers (70.0 ± 7.7 kg; 178 ± 9.4 cm; 24.5 ± 5.3 years; 824 ± 119 FINA points scoring) performed the starts on the OMEGA OSB11 starting block followed by 5 m gliding at maximum velocity. Nineteen comparisons of kinematics variables across start technique were performed with critical alpha adjusted using a Holm's correction to maintain an experiment-wise type I error rate of p

The aim of this study was to examine spatiotemporal characteristics and joint angles during forward and backward walking in water at low and high stride frequency. Eight healthy adults (22.1 ± 1.1 years) walked forward and backward underwater at low (50 pulses) and high frequency (80 pulses) at the xiphoid process level with arms crossed at the chest. The main differences observed were that the participants presented a greater speed (0.58 vs. 0.85 m/s) and more asymmetry of the step length (1.24 vs. 1.48) at high frequency whilst the stride and step length (0.84 vs. 0.7 m and 0.43 vs. 0.35 m, respectively) were lower compared to low frequency (P 0.05). Support phase duration was higher at forward walking than backward walking (61.2 vs. 59.0%). At initial contact, we showed that during forward walking, the ankle and hip presented more flexion than during backward walking (ankle: 84.0 vs. 91.8º and hip: 22.8 vs. 8.0º; P 0.001). At final stance, the knee and hip were more flexed at low frequency than at high frequency (knee: 150.0 vs. 157.0º and hip: -12.2 vs. -14.5º; P 0.001). The knee angle showed more flexion at forward walking (134.0º) than backward walking (173.1º) (P 0.001). In conclusion, these results show how forward and backward walking in water at different frequencies differ and contribute to a better understanding of this activity in training and rehabilitation.

The purpose of this study was to compare the effects of two protocols of post-activation potentiation (PAP) on swim start performance (SS). Fourteen trained swimmers (10 men and 4 women) voluntereed for this study. An intra-group design of randomised repetitive measurements was applied. A previous SS trial, performed after a standard warm up (SWU), served as a reference. Two methods of PAP, performed after one hour of rest, were randomly added to SWU: i) three lunges at 85% of 1 repetition maximum (LWU), and ii) four repetitions on the flywheel device YoYo squat (YWU). Swimmers were tested in an SS eigth minutes after the PAP warm-ups. Kinematic variables were collected using three underwater digital video cameras fixed poolside and operating at 25 Hz, and one high speed camera focused on the block and operating at 300 Hz. Data obtained from the video analysis were processed using a repeated measures analysis of the variance. The mean horizontal velocity of the swimmer's flight improved after both PAP methods, with the greatest improvement after YWU (F2,12= 47.042, p < 0.001; SWU = 3.63±0.11; LWU = 4.15 ± 0.12; YWU = 4.89 ± 0.12 m/s). After YWU, it took the subjects less time to cover a distance of five meters (F2,12 = 24.453, p < 0.001) and fifteen meters (F2,12 = 4.262, p < 0.04). Subjects also achieved a higher mean angular velocity of the knee extension (F2,12 = 23.286, p < 0.001) and a reduction of the time on the block (F2,12 = 6.595, p < 0.05). These results demonstrate that muscle performance in the execution of an SS is enhanced after a warm-up with specific PAP protocols. YWU leads to the greatest improvement in the performance of the swimmer 's start and, therefore, may be specially beneficial in short events. CTS-527: Actividad física y deportiva en el medio acuático

Resumen : La aparicion del paracaidas como nuevo material, que facilita el entre-namiento con nado resistido, hace necesario que los entrenadores conozcan las modificaciones que su utilizacion produce en las variables fisiologicas. El estudio; se realizo con una muestra de 16 nadadores de nivel nacional e internacional comprendi-dos entre los 19 y 24 anos y se les realizan cuatro pruebas que consisten en nadar a crol durante 10 y 45 segundos a maxima intensidad, utilizando el nado normal (NKl) y el-nado resistido con paracaidas (NRCP). En estas pruebas se analizaron las variables de frecuencia cardiaca (Fe) y concentracion de lactato en sangre (Lac). Se aplico un diseno intragrupo y el estudio de los datos se llevo a cabo mediante un analisis de varianza para medidas repetidas. En los resultados obtenidos en la (Fc) puede observarse como la (Fc), es significativamente (p Analizando los resultados, se puede afirmar que el nado resistido con paracaidas produce algunos cambios en las variables fisiologicas, que deben ser analizados por los entrenadores para comprobar si este tipo de entrenamiento es adecuado para sus nadadores.

The purpose of this study was to investigate the association between relay exchange block time and final performance in 4 × 100-m and 4 × 200-m freestyle and 4 × 100-m medley relays as a function of sex (men and women) and classification (medallists and non-medallists) in international competitions. Nineteen international competitions covering a 13-year period (2000-2012) were analysed retrospectively. The data corresponded to a total of 827 team relay histories (407 men, 420 women). Kruskal-Wallis and Mann-Whitney tests were performed to determine any differences by sex, classification, and event. Similarly, the relationship between the exchange block times and final performance was examined by means of a Pearson correlation analysis. In the three events, the men's exchange block times were shorter than those of the women (η(2) = 0.049-0.109; P0.001). The exchange block time was especially relevant for the women's relay medallists in the 4 × 100-m freestyle (r = 0.306, P = 0.021) and 4 × 100-m medley (r = 0.385, P = 0.011), while for men the relationship was clearer for the non-medallists. These results suggest that the exchange block time should be considered as one of the performance parameters of swimming relay starts, and thus should be included explicitly as part of training. In particular, the coach could design training targeted at standardising an optimal exchange block time equal to or less than that expected for other teams in the competition.

The purpose of this study was to ascertain the pacing strategies employed in 200- and 400-m individual medley events and which style was the most determinant for the final performance as a function of sex and classification in international competitions. Twenty-six international competitions covering a 12-year period (2000�2011) were analyzed retrospectively: Olympic Games, World Championships, European Championships, Commonwealth Games, Pan Pacific Games, U.S. Olympic Team Trials, and Australian Olympic Trials. The data corresponded to a total of 1,643 swimmers' competition histories (821 men, 822 women). A 2-way analysis of variance (sex [2 levels: men, women] × classification [3 levels: 1st to 3rd, 4th to 8th, 9th to 16th]) was performed for each stroke (butterfly, backstroke, breaststroke, and freestyle). The Bonferroni post hoc test was used to compare means. Pearson's simple correlation coefficient was used to determine correlations between the style (sections time) and the final performance (total time). The men employed a smaller percentage of their event times in the breaststroke than did the women and a greater percentage in the freestyle in both the 200- and 400-m distances, with the fastest style for both sexes being the butterfly. Considering only the medalists, in men (200 and 400 m), the backstroke was the style that most determined their final performance, whereas in women, it was the backstroke (200 m) or freestyle (400 m). It was concluded that in general the men apply a positive pacing strategy in the 200- and 400-m individual medley events, whereas the women apply a negative pacing strategy. The practical application of the study is that it suggests the need for a differentiated approach in training men and women individual medley swimmers.

The performances of 335 male and female swimmers competing in 50-, 100-, and 200-m freestyle events at the 1992 Barcelona Olympic Games were videotaped and analyzed to determine stroke length (SL), stroke rate (SR), starting time (ST), turning times (TI = turn in, TO = turn out), finishing (end) time (ET), and average velocity (AV); relationships were then determined among these variables in addition to height, weight, age, and final time (FT). Differences were subsequently assessed within and among the events, and comparisons were made between male and female performances. ST, TI, TO, ET, and SL were identified as principal components of successful swimming performance at each distance. Results revealed statistically significant correlations between factors for all events. The men were older and taller; possessed longer stroke lengths; and started, turned, and swam faster than the women. As the race distance increased from 50 to 200 m, ST, TI, TO, SL, and ET increased for both men and women, while age, SR, and AV decreased.