Performance Tiers within a Competitive Age Group of Young Swimmers Are Characterized by Different Kinetic and Kinematic Behaviors

The present study aimed to analyze swimmers’ in-water kinetic and kinematic behaviors according to different swimming performance tiers within the same age group. An amount of 53 highly trained swimmers (girls and boys: 12.40 ± 0.74 years) were split up into 3 tiers based on their personal best performance (i.e., speed) in the 50 m freestyle event (short-course): lower-tier (1.25 ± 0.08 m·s−1); mid-tier (1.45 ± 0.04 m·s−1); and top-tier (1.60 ± 0.04 m·s−1). The in-water mean peak force was measured during a maximum bout of 25 m front crawl using a differential pressure sensors system (Aquanex system, Swimming Technology Research, Richmond, VA, USA) and defined as a kinetic variable, while speed, stroke rate, stroke length, and stroke index were retrieved and considered as kinematic measures. The top-tier swimmers were taller with a longer arm span and hand surface areas than the low-tier, but similar to the mid-tier. While the mean peak force, speed and efficiency differed among tiers, the stroke rate and stroke length showed mixed findings. Coaches should be aware that young swimmers belonging to the same age group may deliver different performance outcomes due to different kinetic and kinematic behaviors.Portuguese Foundation for Science and Technology (FCT),Grants 2020.08326.BD and UIDB04045/202

Analysis and influence of the underwater phase of breaststroke on short-course 50 and 100m performance

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 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

Squat jump and jumping push-up performance of trained swimmers inmediately before and after resistance exercise

Introduction When an action induces acute fatigue, it may be followed by a period of potentiated force production capability, termed as Postactivation Potentiation (Seitz, 2015). The aim of the study was to measure the effect on swimming performance of muscular contractions 5-20 minutes prior to the trials and to determine the possible causes of performance enhancement. Methods 15 Elite Canadian swimmers volunteered to participate in this study. A repeated measures counterbalanced design was used in which swimmers performed 4 different activation protocols in 4 different sessions. Muscle performance was evaluated in each participant performing 3 maximal effort squat jumps, alternated with 3 maximal jumping push-ups. Both assessed from one ground reaction force plate. One bout of loaded conditioning exercise (CE) on the target muscles was randomly applied on the subjects after the basic muscle activation protocol (BME). Four repetitions of loaded back squat were applied when leg muscles were the target (CE-L). Four repetitions of loaded bench-press were applied when upper body muscles were the target group (CE-U). Loaded repetitions of back squat and bench press were combined applied when both limbs were the target (CE-BL). After CE, muscle performance was assessed again at 5, 8, 12 and 20 minutes, regardless the CE applied. One test condition without any CE was also given and acted as a control. Results Impulse in lower limbs was higher in the protocol CE-L (5min: 181.54 N·s; 8 min: 181.78 N·s), in comparison with pretest conditions (Pre: 175.18 N·s; P = 0.05). Impulse was also higher in CE-BL but it was achieved only after 8min of rest (181.16 N·s; p = 0.05) When comparisons with BME were made, the impulse in upper limbs was higher only in CE-U (50.58 N·s; p = 0.05), and this value was obtained at 8 minutes after load. Discussion & Conclusion Improvements obtained in both limbs are in agreement with the physiological explanation of PAP. Changes happened in limbs after specific load application, but no influences were found when load applied in such limb was assessed in the other. Surprisingly, impulse was even higher at minute 8, and such effect achieved, could be related to a difference in involvement of motor units. Thus, although an improvement in performance is obtained after load application, PAP could not be considered only as an acute local effect generated by the myosin phosphorilation. This fact could suggest that some neural factors of the speed-strength behavior could be behind of the performance improvement of the system.CTS-527: Actividad física y deportiva en el medio acuátic

PAP in Swimming Starts: Lunge Vs YoYo Squat

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 acuátic

Turn Performance Variation in European Elite Short-Course Swimmers

This study was supported by a grant awarded 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 Measurements: Applied to the performance improvement' and the Spanish Ministry of Education, Culture and Sport: FPU17/02761 grants.Turn performances are important success factors for short-course races, and more consistent turn times may distinguish between higher and lower-ranked swimmers. Therefore, this study aimed to determine coefficients of variation (CV) and performance progressions ( increment %) of turn performances. The eight finalists and eight fastest swimmers from the heats that did not qualify for the semi-finals, i.e., from 17th to 24th place, of the 100, 200, 400, and 800 (females only)/1500 m (males only) freestyle events at the 2019 European Short Course Championships were included, resulting in a total of 64 male (finalists: age: 22.3 +/- 2.6, FINA points: 914 +/- 31 vs. heats: age: 21.5 +/- 3.1, FINA points: 838 +/- 74.9) and 64 female swimmers (finalists: age: 22.9 +/- 4.8, FINA points: 904 +/- 24.5 vs. heats: age: 20.1 +/- 3.6, FINA points: 800 +/- 48). A linear mixed model was used to compare inter- and intra-individual performance variation. Interactions between CVs, increment %, and mean values were analyzed using a two-way analysis of variance (ANOVA). The results showed impaired turn performances as the races progressed. Finalists showed faster turn section times than the eight fastest non-qualified swimmers from the heats (p < 0.001). Additionally, turn section times were faster for short-, i.e., 100 and 200 m, than middle- and long-distance races, i.e., 400 to 1500 m races (p < 0.001). Regarding variation in turn performance, finalists showed lower CVs and increment % for all turn section times (0.74% and 1.49%) compared to non-qualified swimmers (0.91% and 1.90%, respectively). Similarly, long-distance events, i.e., 800/1500 m, showed lower mean CVs and higher mean increment % (0.69% and 1.93%) than short-distance, i.e., 100 m events (0.93% and 1.39%, respectively). Regarding turn sections, the largest CV and increment % were found 5 m before wall contact (0.70% and 1.45%) with lower CV and more consistent turn section times 5 m after wall contact (0.42% and 0.54%). Non-qualified swimmers should aim to match the superior turn performances and faster times of finalists in all turn sections. Both finalists and non-qualified swimmers should pay particular attention to maintaining high velocities when approaching the wall as the race progresses.Ministry of Science, Innovation and Universities (Spanish Agency of Research)European Commission PGC2018-102116-B-I00Spanish Government FPU17/0276

Strength-velocity relationship of resisted swimming: A regression analysis

This study explored how external loads affect semi-tethered resisted swimming (STRS). Twenty national competitive swimmers (age: 18.31 ± 1.42 years) participated in an incremental STRS test. Pearson product-moment correlation coefficients between the load and the swimming variables were obtained, and simple linear regression analyses were applied to evaluate the associations. The results showed that less velocity and acceleration were delivered at high loads (p < 0.001). It increased the velocity fluctuation, affecting the swimming patterns adversely. A decrease in the impulse relative to the load pulled is obtained, especially after 20-30% of the maximal load (R2 = 0.724, p < 0.000). Coaches should reconsider using STRS, as little benefits may be obtained in performance.This work was supported by the projects DEP 2014-59707-P “SWIM: Specific Water Innovative Measurements” and PGC2018-102116-B-I00 “SWIM II”, granted by the Spanish Research Agency and European Regional Development Fund (ERDF)

How post-activation performance enhancements affect semi-tethered swimming kinetics

Introduction: When an action induces acute fatigue, it may be followed by a period of potentiated force production capability, termed as Post-activation Potentiation (PAP). One of the training philosophy principles PAP is based on is complex training, which consists on providing a resistive conditioning exercise as similar as possible to the real action before performing a sport-specific activity involving similar muscle groups. Nevertheless, a key criticism of inducing PAP in swimming is that the conditioning exercises applied in dry-land conditions may reduce the stimulus intensity or effectiveness. This study aimed to test if muscular performance might be elevated in semi-tethered swimming test by using a specific dry-land resistance warm-up simulating the arm-stroke pull of swimming. Methods: Ten competitive swimmers conducted an incremental semi-tethered swimming test on a Smith Machine adapted through a pulley system. Six minutes of rest were given between every maximal swimming effort (to 15m). Kinetic variables were obtained through a linear encoder connected to the Smith Machine’s bar, which allowed to individually identifying the related results according to the load that maximized maximal power output. On a different day, a trial with the same aforementioned load was performed after the experimental warm-up (3 arm-stroke repetitions at 85% 1RM). Statistical differences between the variables were determined using a repeated measures 1-way ANOVA. Results: The values were better when obtained during incremental testing, rather than obtained after PAP; the Intracyc Acceleration Variation delivered to the load was lower after PAP warm-up (p = 0.012; 6.08 ± 1.32 vs 4.68 ± 1.25 m/s2), mainly because the Force and Impulse applied per stroke were lower (p = 0.013; -20.71%; p = 0.002; -21.72%, respectively). Swimming Velocity (p = 0.001; 1.20 ± 0.14 vs 0.99 ± 0.15 m/s) and Swimming Power (p = 0.002; 51.35 ± 15.43 vs. 42.33 ± 13.03 W) were lower after PAP and kinematic variables were also negatively affected. Conclusion: A dry-land warm-up may not be an efficient approach to stimulate performance skills on swimming. Possibly an attenuation effect is obtained on muscle fibers from a high-resistance isokinetic exercise performed at low speed. Nevertheless, is worthy of review that maximal swimming power output was achieved at 56% of the maximal load. It meant that at least 1 to 3 efforts were performed by every subject prior the execution of the selected trial. As fatigue impairs performance, more fatigue accumulation was expected to occur during that trial in comparison to the only trial performed after PAP; however it did not happen. Possibly, the combination of specific in-water resistance exercise and the time of rest given between trials constituted an effective way to get recovered from fatigue while potentiation still existed. Future studies should consider if swimmers may benefit of semi-tethered low loaded swimming as a way to induce PAP. Acknowledgements: DEP2014-59707-P: SWIM: Specific Water Innovative Measurements, applied to the development of International Swimmers in Short Swimming Events (50and100m).CTS-527: Actividad física y deportiva en el medio acuátic

STRENGTH-VELOCITY RELATIONSHIP OF RESISTED SWIMMING: A REGRESSION ANALYSIS

This study explored how external loads affect semi-tethered resisted swimming (STRS). Twenty national competitive swimmers (age: 18.31 ± 1.42 years) participated in an incremental STRS test. Pearson product-moment correlation coefficients between the load and the swimming variables were obtained, and simple linear regression analyses were applied to evaluate the associations. The results showed that less velocity and acceleration were delivered at high loads (p \u3c 0.001). It increased the velocity fluctuation, affecting the swimming patterns adversely. A decrease in the impulse relative to the load pulled is obtained, especially after 20-30% of the maximal load (R2 = 0.724, p \u3c 0.000). Coaches should reconsider using STRS, as little benefits may be obtained in performance

Post-eccentric flywheel underwater undulatory swimming potentiation in competitive swimmers

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