Lower fatigue and faster recovery of ultra-short race pace swimming training sessions.

Ultra-short race-pace training (USRPT) is a high-intensity training modality used in swimming for the development of specific race-technique. However, there is little information about the fatigue associated to this modality. In a crossover design, acute responses of two volume-equated sessions (1000-m) were compared on 14 national swimmers: i) USRPT: 20×50-m; ii) RPT: 10×100-m. Both protocols followed an equivalent work-recovery ratio (1:1) based on individual 200-m race-pace. The swimming times and the arm-strokes count were monitored on each set and compared by mixed-models. Blood lactate [La-] and countermovement jump-height (CMJ) were compared within and between conditions 2 and 5 min after the protocols. The last bouts in RPT were 1.5-3% slower than the target pace, entailing an arm-strokes increase of ~0.22 for every second increase in swimming time. USRPT produced lower [La-] ([Mean ± standard deviation], 2 min: 8.2±2.4 [p = 0.021]; 5 min: 6.9±2.8 mM/L [p = 0.008]), than RPT (2 min: 10.9±2.3; 5 min: 9.9±2.4 mM/L). CMJ was lowered at min 2 after RPT (-11.09%) and USRPT (-5.89%), but returned to baseline in USRPT at min 5 of recovery (4.07%). In conclusion, lower fatigue and better recovery were achieved during USRPT compared to traditional high-volume set.

Are the 50 m Race Segments Changed From Heats to Finals at the 2021 European Swimming Championships?

This study explored in the 50 m races of the four swimming strokes the performance parameters and/or technical variables that determined the differences between swimmers who reach the finals and those who do not. A total of 322 performances retrieved from the 2021 Budapest European championships were the focus of this study. The results of the performances achieved during the finals compared to the heats showed that the best swimmers did not excel during the heats, as a significant progression of performance was observed in most of the strokes as the competition progressed. Specifically, combining men and women, the swimmers had in freestyle a mean coefficient of variation (CV) of ∼0.6%, with a mean range of performance improvement (∆%) of ∆ = ∼0.7%; in breaststroke a mean CV of ∼0.5% and ∆ = -0.2%; in backstroke a mean CV of ∼0.5% and ∆ = -0.6%, and; in butterfly a mean CV of ∼0.7% and ∆ = -0.9%. For all strokes, it was a reduction of the underwater phase with the aim of increasing its speed. However, this result was not always transferred to the final performance. In any case, most of the swimmers tried to make improvements from the start of the race up to 15 m. Furthermore, the swimmers generated an overall increase in stroke rate as the rounds progressed. However, a decrease in stroke length resulted and, this balance appeared to be of little benefit to performance.

Biophysical Impact of 5-Week Training Cessation on Sprint Swimming Performance.

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 (V˙O2) 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 < .05), despite similar stroke length and stroke index (P > .05). Blood lactate concentrations remained similar (P > .05), but V˙O2 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 < .05). Anaerobic metabolic power deterioration was only observed in males (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 < .05). 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.

Quantification of swimmers' ability to apply force in the water: the potential role of two new variables during tethered swimming.

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 calculated 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.

Swimming with Swimsuit and Wetsuit at Typical vs. Cold-water Temperatures (26 vs. 18 ℃).

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), V̇O2 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 V̇O2peak, [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 ℃.

Understanding the effects of training on underwater undulatory swimming performance and kinematics.

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.

Effects of 2 Types of Activation Protocols Based on Postactivation Potentiation on 50-m Freestyle Performance.

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.

Protocolización de la post-activación potenciación estimulada en natación y su relación con la fuerza relativa / Protocolization of post-activation performance enhancements in swimming and its relationship with the relative strength

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 tres saltos verticales y tres 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

OBJETIVO: Este estudo tentou um protocolo de aprimoramento de desempenho pós-ativação (PAPE) em 16 nadadores treinados. MÉTODO: Primeiro, exercícios de condicionamento máximo para membros superiores e inferiores foram aplicados e testados após 5, 8, 12 e 20 minutos de descanso através do teste de contrações voluntárias máximas (3 repetições de salto vertical e 3 repetições de flexão voadora). Em uma sessão subsequente, exercícios específicos de condicionamento foram aplicados novamente em ambos os membros e seus efeitos foram avaliados em uma corrida de natação de 50 m após proporcionar o mesmo tempo de descanso em que o melhor desempenho foi detectado (8 min). Por fim, o índice de força relativa foi obtido em todos os participantes para estudar a relação com as variáveis de desempenho na natação. RESULTADOS: Todas as variáveis relacionadas à natação iniciaram o desempenho. A velocidade durante o vôo foi maior devido ao aumento das forças produzidas contra o bloco. O tempo de natação para 50-m foi semelhante ao obtido após a condição padrão, embora as velocidades de natação fossem maiores no início da corrida. CONCLUSÕES: Os indivíduos com maior índice de força relativa obtiveram melhores resultados e reagiram melhor ao aprimoramento de desempenho pós-ativação, possivelmente por seus efeitos serem maiores nas fibras do tipo II e serem mais frequentes em indivíduos treinados

Post high intensity pull-over semi-tethered swimming potentiation in national competitive swimmers.

BACKGROUND: 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. METHODS: 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<0.05. RESULTS: DLWU increased RFD (34.52±16.55 vs. 31.29±13.70 N/s; Δ=9.35%) and stroke-rate (64.70±9.84 vs. 61.56±7.07 Hz; Δ=5.10%) compared to SWU, but decreased velocity, force, acceleration, impulse and power. During the incremental-load test velocity and power were higher than obtained after SWU (1.21±0.14 vs. 1.17±0.12 m/s; Δ=3.06%), (51.38±14.93 vs. 49.98±15.40 W; Δ=2.72%), suggesting enhancements prompted by the test itself. Correlations between stroke-length with impulse (r=0.76) and power (r=0.75) associated kinetics with kinematics. CONCLUSIONS: Potentiation responses were present after the dry-land warm-up. However, swimmers may benefit more from submaximal prolonged conditioning activities such as resisted swimming rather than high-resistance dry-land sets to obtain performance enhancements.

Is Swimmers' Performance Influenced by Wetsuit Use?

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 < .001). Maximal HR, maximal blood lactate concentration, rating of perceived exertion, stroke rate, and propelling efficiency were similar when using both swimsuits, but SL and stroke index presented higher values with the wetsuit in both the swimming pool and the swimming flume. Comparing swimming conditions, maximal HR and maximal blood lactate concentration were lower, and SL, stroke index, and propelling efficiency were higher when swimming in the flume than when swimming in the pool with both suits. 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.

Eccentric flywheel post-activation potentiation influences swimming start performance kinetics.

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 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.

Nonlocalized postactivation performance enhancement (PAPE) effects in trained athletes: a pilot study.

Fifteen trained athletes were assessed for postactivation performance enhancement (PAPE) of squat jumps (SJs) and power push-ups (PPUs) following upper body activation, lower body activation, upper and lower body activation, and rest. SJ improved similarly across all 4 conditions. PPU could not be assessed. Since the test protocol of SJ and PPU involved upper and lower body activation and caused PAPE in SJ, future work is required to determine if a nonlocalized PAPE effect exists.

Does Swimming at a Moderate Altitude Favor a Lower Oxidative Stress in an Intensity-Dependent Manner? Role of Nonenzymatic Antioxidants.

Casuso, Rafael A., Jerónimo Aragón-Vela, Gracia López-Contreras, Silvana N. Gomes, Cristina Casals, Yaira Barranco-Ruiz, Jordi J. Mercadé, and Jesus R. Huertas. Does swimming at a moderate altitude favor a lower oxidative stress in an intensity-dependent manner? Role of nonenzymatic antioxidants. High-Alt Med Biol. 18:46-55, 2017.-we aimed to describe oxidative damage and enzymatic and nonenzymatic antioxidant responses to swimming at different intensities in hypoxia. We recruited 12 highly experienced swimmers who have been involved in competitive swimming for at least 9 years. They performed a total of six swimming sessions carried out at low (LOW), moderate (MOD), or high (HIGH) intensity at low altitude (630 m) and at 2320 m above sea level. Blood samples were collected before the session (Pre), after the cool down (Post), and after 15 minutes of recovery (Rec). Blood lactate (BL) and heart rate were recorded throughout the main part of the session. Average velocities did not change between hypoxia and normoxia. We found a higher BL in response to MOD intensity in hypoxia. Plasmatic hydroperoxide level decreased at all intensities when swimming in hypoxia. This effect coincided with a lower glutation peroxidase activity and a marked mobilization of the circulating levels of α-tocopherol and coenzyme Q10 in an intensity-dependent manner. Our results suggest that, regardless of the intensity, no oxidative damage is found in response to hypoxic swimming in well-trained swimmers. Indeed, swimmers show a highly efficient antioxidant system by stimulating the mobilization of nonenzymatic antioxidants.

[Not Available]. / Influencia del programa SWEP (Study Water Exercise Pregnant) en los resultados perinatales: protocolo de estudio

Introduction: Moderate exercise training during the pregnancy benefits both the pregnant woman and the fetus. The research papers consulted have linked physical activity with the reduction of the number of cesareans, instrumental delivery and with a more physiological delivery. It also prevents excessive weight gain in women and decreases the risk of gestational diabetes and high blood pressure. Aim: The aim of this research is to know if an exercise program of moderate character with Water Study Exercise Pregnant (SWEP) method, performed in an aquatic environment, contributes to have more favorable results in the perinatal period, both for women and baby. Material and methods: The design is a randomized clinical trial. The sample will consist of 364 pregnant women, with a total universe of 6,579 births occurred in Granada (Spain) during 2014. The sample was divided into two groups, intervention group and control group. The activity will be carried out in the water sporting facilities of the Faculty of Sports Science of the University of Granada, which have two pools suitable for our purposes: a 25-meter polyvalent pool and a 12.5-meter pool for training. Results: The exercise program designed specifically for the project called SWEP is performed from 20 to 37 weeks of gestation (SG), and it consists of three weekly sessions, with duration of 60 minutes each. Sessions will include three phases: warm-up phase, the main phase in which the exercise is divided into an aerobic phase and strength training and endurance training phase and a final phase of stretching and relaxation. The variables that will be studied are: a) Maternal: weight, BMI, blood pressure, O'Sullivan test, postpartum depression, level of self-rated health, sleep quality and perceived exertion during physical activity; b) fetal: weight, Apgar scores, head circumference and GA (Gestational age); c) peripartum: time dilation, expulsion and delivery, type of delivery, episiotomy, type of feed received by the RN and time of exclusive breastfeeding; and d) descriptive: age, occupation, education level, type of exercise done before and OF (obstetric formula). Conclusion: With aquatic moderate physical activity during pregnancy (method SWEP), we intended to improve the variables above.

Introducción: El entrenamiento mediante ejercicio físico moderado durante el periodo de gestación aporta beneficios tanto a la mujer embarazada como al feto. Los trabajos de investigación consultados vinculan la actividad física con una reducción del número de cesáreas, de partos instrumentados y con un parto más fisiológico. Previene igualmente la ganancia excesiva de peso de la mujer, disminuye el riesgo de diabetes gestacional y de hipertensión arterial. Objetivo: El objetivo de esta investigación es conocer si un programa de ejercicio físico de carácter moderado con el método Study Water Exercise Pregnant (SWEP), realizado en un medio acuático, contribuye a obtener unos resultados más favorables en la etapa perinatal, tanto para la mujer como para el bebé. Material y métodos: El diseño que se llevará a cabo es un ensayo clínico aleatorizado. La muestra estará constituida por 364 gestantes, obtenida de un universo total de 6.579 partos acontecidos en Granada (España) durante el año 2014. Dicha muestra se ha dividido en dos grupos, uno de intervención y otro de control. La actividad se realizará en las instalaciones deportivas acuáticas de la Facultad de Ciencias del Deporte de la Universidad de Granada, que cuentan con dos vasos adecuados a nuestros objetivos, uno polivalente de 25 metros y otro de enseñanza de 12,5 metros. Resultados: El programa de ejercicios diseñado específicamente para el proyecto denominado SWEP, abarca desde la 20 hasta la 37 semana de gestación (SG) y consta de tres sesiones semanales, con una duración de 60 minutos cada una. Las sesiones incluirán tres fases: fase de calentamiento, fase principal en la que el ejercicio se divide en una parte aeróbica y otra de ejercicios de fuerza y resistencia y una final con estiramientos y relajación. Las variables que se van a estudiar son las siguientes: a) maternas: peso, IMC, tensión arterial, test de O´Sullivan, aparición de depresión postparto, nivel de autopercepción de salud, calidad del sueño y esfuerzo percibido durante la actividad física; b) fetales: peso, test de Apgar, perímetro cefálico y SG (semana de gestación al nacimiento); c) periparto: tiempos de dilatación, expulsivo y alumbramiento, tipo de parto, presencia de episiotomía, tipo de alimentación que recibe el RN y tiempo de lactancia materna exclusiva; y d) descriptivas: edad, profesión, nivel de estudios, tipo de ejercicio físico realizado previamente y FO (fórmula obstétrica). Conclusión: Con la actividad física acuática moderada, por parte de la embarazada (método SWEP), se pretenden mejorar las variables arriba indicadas.

Influencia del programa SWEP (Study Water Exercise Pregnant) en los resultados perinatales: protocolo de estudio / Influence of SWEP (Study Pregnant Water Exercise) program in perinatal outcomes: Study protocol

Introducción: el entrenamiento mediante ejercicio físico moderado durante el periodo de gestación aporta beneficios tanto a la mujer embarazada como al feto. Los trabajos de investigación consultados vinculan la actividad física con una reducción del número de cesáreas, de partos instrumentados y con un parto más fisiológico. Previene igualmente la ganancia excesiva de peso de la mujer, disminuye el riesgo de diabetes gestacional y de hipertensión arterial. Objetivo: el objetivo de esta investigación es conocer si un programa de ejercicio físico de carácter moderado con el método Study Water Exercise Pregnant (SWEP), realizado en un medio acuático, contribuye a obtener unos resultados más favorables en la etapa perinatal, tanto para la mujer como para el bebé. Material y métodos: el diseño que se llevará a cabo es un ensayo clínico aleatorizado. La muestra estará constituida por 364 gestantes, obtenida de un universo total de 6.579 partos acontecidos en Granada (España) durante el año 2014. Dicha muestra se ha dividido en dos grupos, uno de intervención y otro de control. La actividad se realizará en las instalaciones deportivas acuáticas de la Facultad de Ciencias del Deporte de la Universidad de Granada, que cuentan con dos vasos adecuados a nuestros objetivos, uno polivalente de 25 metros y otro de enseñanza de 12,5 metros. Resultados: el programa de ejercicios diseñado específicamente para el proyecto denominado SWEP, abarca desde la 20 hasta la 37 semana de gestación (SG) y consta de tres sesiones semanales, con una duración de 60 minutos cada una. Las sesiones incluirán tres fases: fase de calentamiento, fase principal en la que el ejercicio se divide en una parte aeróbica y otra de ejercicios de fuerza y resistencia y una final con estiramientos y relajación. Las variables que se van a estudiar son las siguientes: a) maternas: peso, IMC, tensión arterial, test de O´Sullivan, aparición de depresión postparto, nivel de autopercepción de salud, calidad del sueño y esfuerzo percibido durante la actividad física; b) fetales: peso, test de Apgar, perímetro cefálico y SG (semana de gestación al nacimiento); c) periparto: tiempos de dilatación, expulsivo y alumbramiento, tipo de parto, presencia de episiotomía, tipo de alimentación que recibe el RN y tiempo de lactancia materna exclusiva; y d) descriptivas: edad, profesión, nivel de estudios, tipo de ejercicio físico realizado previamente y FO (fórmula obstétrica). Conclusión: con la actividad física acuática moderada, por parte de la embarazada (método SWEP), se pretenden mejorar las variables arriba indicadas (AU)

Introduction: Moderate exercise training during the pregnancy benefits both the pregnant woman and the fetus. The research papers consulted have linked physical activity with the reduction of the number of cesareans, instrumental delivery and with a more physiological delivery. It also prevents excessive weight gain in women and decreases the risk of gestational diabetes and high blood pressure. Aims: The aim of this research is to know if an exercise program of moderate character with Water Study Exercise Pregnant (SWEP) method, performed in an aquatic environment, contributes to have more favorable results in the perinatal period, both for women and baby. Material and methods: The design is a randomized clinical trial. The sample will consist of 364 pregnant women, with a total universe of 6,579 births occurred in Granada (Spain) during 2014. The sample was divided into two groups, intervention group and control group. The activity will be carried out in the water sporting facilities of the Faculty of Sports Science of the University of Granada, which have two pools suitable for our purposes: a 25-meter polyvalent pool and a 12.5-meter pool for training. Results: The exercise program designed specifically for the project called SWEP is performed from 20 to 37 weeks of gestation (SG), and it consists of three weekly sessions, with duration of 60 minutes each. Sessions will include three phases: warm-up phase, the main phase in which the exercise is divided into an aerobic phase and strength training and endurance training phase and a final phase of stretching and relaxation. The variables that will be studied are: a) Maternal: weight, BMI, blood pressure, O’Sullivan test, postpartum depression, level of self-rated health, sleep quality and perceived exertion during physical activity; b) fetal: weight, Apgar scores, head circumference and GA (Gestational age); c) peripartum: time dilation, expulsion and delivery, type of delivery, episiotomy, type of feed received by the RN and time of exclusive breastfeeding; and d) descriptive: age, occupation, education level, type of exercise done before and OF (obstetric formula). Conclusion: With aquatic moderate physical activity during pregnancy (method SWEP), we intended to improve the variables above (AU)

Biomechanical characteristics of adults walking forward and backward in water at different stride frequencies.

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.

Effect on swimming start performance of two types of activation protocols: lunge and YoYo squat.

The purpose of this study was to compare the effects of 2 protocols of postactivation potentiation (PAP) on swimming start perfomance (SS). Fourteen trained swimmers (10 men and 4 women) volunteered for this study. An intragroup design of randomized 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 1 hour of rest, were randomly added to the SWU: (a) 3 lunges at 85% of 1 repetition maximum (LWU) and (b) 4 repetitions on the flywheel device YoYo squat (YWU). Swimmers were tested in an SS 8 minutes after the PAP warm-ups. Kinematic variables were collected using 3 underwater digital video cameras fixed poolside and operating at 25 Hz, and 1 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 ± 0.122; YWU = 4.89 ± 0.12 m·s). After YWU, it took the subjects less time to cover a distance of 5 m (F2,12 = 24.453, p < 0.001) and 15 m (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 especially beneficial in short events.

Kinematic Adaptations of Forward And Backward Walking on Land and in Water.

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<0.05). At initial contact, knees and hips were more flexed during walking forward in water, whilst, ankles were more dorsiflexed during walking backward in water. At final stance, knees and ankles were more flexed during forward walking, whilst the hip was more flexed during backward walking. These results show how walking in water differs from walking on land, and provide valuable insights into the development and prescription of rehabilitation and training programs.

La exposición aguda a altitud previene el estrés oxidativo por una movilización del alfa-tocoferol plasmático / Acute exposure to moderate altitude prevents oxidative stress by a plasmatic alpha-tocopherol mobilization

Introducción: Existe gran controversia sobre el efecto de la hipoxia en el estatus oxidativo de deportistas; por otra parte, la mayoría de estudios analizan los mecanismos de adaptación tras un periodo de aclimatación y no contemplan el efecto de las exposiciones agudas. Así, nuestro estudio pretende comprobar el efecto del ejercicio y la exposición aguda a una altitud moderada sobre el estrés oxidativo en nadadores. Material y método: Diez nadadores entrenados (5 mujeres, 5 hombres) realizaron dos sesiones idénticas de entrenamiento de 90 minutos, una a 630 m (normoxia) y otra a 2320 m de altitud (hipoxia); ambas se ajustaron para generar valores de lactato ligeramente superiores al umbral anaeróbico. Se extrajeron 5 ml de sangre en reposo y tras el esfuerzo. Las muestras fueron centrifugadas para la obtención de plasma y congeladas a -80ºC. Como marcador de peroxidación lipídica se determinaron concentraciones de hidroperóxidos y sustancias reactivas al ácido tiobarbitúrico (TBARS). Como mecanismo antioxidante no enzimático se cuantificó el alfa-tocoferol. Las comparaciones de medias se realizaron con una ANOVA de un factor. Resultados: La exposición a hipoxia produjo un descenso significativo de TBARS (20,78±8,36 nmol/ml, p<0,03) y, tras el esfuerzo, de hidroperóxidos (20,78±8,36 nmol/ml, p<0,03) en hombres. En nadadores de ambos sexos, el alfa-tocoferol disminuyó significativamente debido a la hipoxia (hombres: 23,06±4,26 nmol/ml, mujeres: 19,51±4,26 nmol/ml, p<0,001). En normoxia, las mujeres presentaron menor concentración de TBARS (20,54±8,36 nmol/ml, p<0,03) e hidroperóxidos (2,16±0,87 nmol/ml, p<0,03) que los hombres. La sesión de entrenamiento no modificó dichas variables. Conclusiones: En estudios previos demostramos una movilización de antioxidantes no enzimáticos desde plasma a tejidos muscular y hepático en situaciones de estrés oxidativo. Concluimos que una exposición aguda a altitud moderada podría prevenir el estrés oxidativo en nadadores debido a una rápida movilización del alfa-tocoferol plasmático (AU)

Introduction: There is a controversy concerning to the modulation of hypoxia-induced oxidative stress; in addition, most studies covered mechanism of adaptation to altitude after an acclimation period, and they did not test the effects of acute exposures to hypoxia. Thus, the aim of the study was to establish oxidative status of trained swimmers analyzing the effects of exercise and acute exposure to moderate altitude. Materials and methods: Ten well-trained swimmers (5 females, 5 males) performed two similar mild-intensity training sessions of 90 minutes, one at an altitude of 630 m (normoxia) and the second of 2320 m (hypoxia). Training sessions were regulated to generate blood lactate values slightly higher than anaerobic threshold. 5 ml of blood samples were collected before and immediately after the exercise. Plasma were obtained by blood-centrifugation, samples were stored at -80ºC until analysis. Lipid peroxidation markers were hydroperoxides and thiobarbituric acid reactive substances (TBARS). Alpha-tocopherol was analyzed as non-enzymatic antioxidant mechanism. Comparisons between means were performed using one-way ANOVA. Results: Acute exposure to hypoxia produced a significant decrease of TBARS (20.78±8.36 nmol/ml, p<0.03) and, after effort, of hydroperoxides (20.78±8.36 nmol/ml, p<0.03) in men. In swimmers of both sexes, plasmatic alpha-tocopherol significantly decreased by hypoxia (men: 23.06±4.26 nmol/ml, women: 19.51±4.26 nmol/ml, p<0.001). In normoxia condition, women presented lower concentrations of TBARS (20.54±8.36 nmol/ml, p<0.03) and hydroperoxides (2.16±0.87 nmol/ml, p<0.03) than men. Mild-intensity training session did not modify oxidative stress in well-trained swimmers. Conclusions: In previous studies we demonstrated a non-enzymatic antioxidant mobilization from plasma to muscular and hepatic tissues as a response to an oxidative stress situation. Therefore, we conclude that acute exposure to moderate altitude could prevent oxidative stress in swimmers by a fast mobilization of plasmatic alpha-tocopherol (AU)