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Antecedentes: Diferentes variables afectan a la obtención del rendimiento en categoría absoluta. Existiendo gran controversia sobre el efecto de la especialización temprana en la obtención de rendimiento en posteriores categorías. Objetivos: El objetivo del presente estudio es analizar el efecto de la especialización temprana en natación. Además, observar la progresión de los nadadores españoles y estadounidenses que han participado en la final en Campeonatos del mundo en categoría junior, comprobando si logran obtener rendimiento en finales de Juegos Olímpicos y Campeonatos del Mundo absoluto entre los años 2006 y 2021, de todos los estilos y distancias. Método: La base de datos final está formada por 268 nadadores. Análisis descriptivos tales como conteo, tablas de contingencia se realizaron para saber el número total de nadadores en función del género y la categoría, también para conocer el número de nadadores en cada estilo en función de la competición y el país perteneciente, y por último para el tiempo medio de cada prueba. Resultados: Los resultados mostraron un mayor número de nadadores finalistas de EE. UU. en todos los estilos de las competiciones, y con un mayor número de participantes en estilo libre. De los nadadores junior 77 (28.41%) únicamente 7 (2.58%) nadadores llegaron a las finales de Campeonatos del Mundo junior, Campeonatos del Mundo absoluto y Juegos Olímpicos. Conclusiones: En conclusión, ser finalista de los Campeonatos del Mundo junior no influye en el éxito en las finales de Campeonatos del Mundo absoluto y Juegos Olímpicos para nadadores españoles y estadounidenses. Palabras clave: especialización temprana, natación, talento, rendimiento

The underwater phase is perhaps the most important phase of the swimming start. To improve performance during the underwater phase, it is necessary to improve our understanding of the key variables affecting this phase. The main aim of this study was to identify key kinematic variables that are associated with the performance of an underwater glide of a swimming start, when performed at streamlined position without underwater undulatory swimming. Sixteen experienced swimmers performed 48 track starts and 20 kinematic variables were analysed. A multiple linear regression analysis was carried out to explore the relationship between glide performance (defined as glide distance) and the variables that may affect glide performance. Four variables in the regression model were identified as good predictors of glide distance: flight distance; average velocity between 5 m and 10 m; and maximum depth of the hip. The results of the present study help improve our understanding of underwater glide optimisation and could potentially facilitate improvement of overall start performance. pre-print 153 KB

Objetivo: Analizar la influencia de diferentes intensidades de nado en los sectores de ciclismo y carrera a pie y en el rendimiento final del triatlón sprint. Métodos: Siete triatletas sub23 y Absolutos (altura de 1,74 ± 0,04 m, peso de 70,82 ± 6,76 kg, edad de 23,42 ± 3,25 años, VO2 max de 63,54 ± 5,23 ml·kg-1·min-1) participaron en este estudio. Realizaron tres triatlones completos a intensidades de nado diferentes (70%, 80% y 90% de un test de 750m previo). Se midió la frecuencia cardíaca y el lactato al finalizar cada sector y el triatlón completo. Resultados: La intensidad de nado del 90% obtuvo el mejor rendimiento final. El lactato y frecuencia cardíaca en el sector de nado para esta condición incrementó significativamente, sin diferencias en los sectores siguientes. Conclusiones: Basándonos en la muestra estudiada, el rendimiento final en un triatlón sprint parece estar condicionado por la intensidad de nado, siendo el 90% la mejor intensidad observada en triatletas moderadamente entrenados.

The purpose of this analysis was to quantify the probability of achieving a top-3 finishing position during 800-m races at a global championship, based on dispersion of the runners during the first and second laps and the difference in split times between laps. Overall race times, intermediate and finishing positions and 400 m split times were obtained for 43 races over 800 m (21 men’s and 22 women’s) comprising 334 individual performances, 128 of which resulted in higher positions (top-3) and 206 the remaining positions. Intermediate and final positions along with times, the dispersion of the runners during the intermediate and final splits (SS1 and SS2), as well as differences between the two split times (Dsplits) were calculated. A logistic regression model was created to determine the influence of these factors in achieving a top-3 position. The final position was most strongly associated with SS2, but also with SS1 and Dsplits. The Global Significance Test showed that the model was significant (p < 0.001) with a predictive ability of 91.08% and an area under the curve coefficient of 0.9598. The values of sensitivity and specificity were 96.8% and 82.5%, respectively. The model demonstrated that SS1, SS2 and Dplits explained the finishing position in the 800-m event in global championships.

The present study examines the association between the success at junior and senior level for British swimmers in World Championships (WCs). It also explores the relationships between swimming performance and the swimmers’ gender, swim stroke, distance, status (finalist, semifinalist and heats) and swimming category. Data were collected for swimmers participating in junior and/or senior World Championships (29,000 entries: 5585 swimmers) from 2006–2017. The final filtered database included only swimmers from the United Kingdom (836 entries: 141 swimmers). A descriptive analysis was made to characterize the swimmers who reached elite status in the senior category. A lineal regression model was run by gender to predict the influence of category, swim stroke, and distance in the results reached in the senior category. The results showed that the ratio of conversion from junior to senior was quite low. Females who participated in both junior and senior WCs were likely to reach top positions in the senior category. Overall, few British swimmers participated in a junior category before the senior level, but female swimmers participating in both junior and senior WCs were likely to reach top positions in the senior category. post-print 335 KB

This study used a power rack device to evaluate the effects of 2 different approaches to resisted swim training loads on swimming strength and performance. Sixteen male, youth national-level swimmers (mean age, 16.22 ± 2.63 years; body height, 169 ± 10.20 cm; body mass, 61.33 ± 9.90 kg) completed a 6-week specific strength-training program, and were then randomly assigned to one of the two groups: a standard training group (GS, n = 8) and a flat pyramid-loading pattern group (GP, n = 8). Strength and power tests along with specific swimming tests (50-m crawl and 50-m competition-style time trials) were conducted at baseline (pre-test), before the third week (mid-test), and after 6 weeks of intervention (post-test). Isokinetic swim bench tests were conducted to obtain measurements of force production and power, and 1RM tests with the power rack system were conducted to measure the maximum drag load (MDL) and specific swimming power. Following 6 weeks of intervention, the mean MDL increased (p < 0.05) by 13.94%. Scores for the 50-m competition style and 50-m crawl time trials improved by 0.32% and 0.78%, respectively, in the GP; however, those changes were not statistically significant. The GS significantly increased their time in the 50-m competition style by 2.59%, and their isokinetic force production decreased by 14.47% (p < 0.05). The 6-week strength-training program performed with the power rack device in a pyramidal organization was more effective than a standard linear load organization in terms of producing improvements in the MDL; however, it did not produce significant improvements in performance. The use of a strength-training program with a pyramidal organization can be recommended for specific strength-training in young swimmers during a preparatory period. However, in our study, that program did not produce significant changes in 50-m crawl and main competition style performance.

Swimming coaches have prescribed dry-land training programs over the years to improve the overall swimming performance (starts, clean swimming, turns and finish). The main aim of the present systematic review was to examine the effects of dry-land strength and conditioning programs on swimming turns. Four online databases were scrutinised, data were extracted using the Preferred PRISMA guidelines and the PEDro scale was applied. A total of 1259 articles were retrieved from database searches. From the 19 studies which were full-text evaluated, six studies were included in the review process. The review indicated that plyometric, strength, ballistic and core training programs were implemented for improving swimming turn performance. Strength, ballistic and plyometric training focusing on neural enhancement seem to be effective for improving swimming turn performance. The data related to training of the core were not conclusive. Coaches should consider incorporating exercises focusing on improving the neuromuscular factor of the leg-extensor muscles into their daily dry-land training programs. More researches are needed to provide a better understanding of the training methods effects and training organisations for improving swimming turn performance. post-print 626 KB

Oxygen cost of running is largely influenced by endurance training strategies, including interval and continuous training. However, which training method better reduces the oxygen cost remains unknown. This study aimed to systematically review the scientific literature and performs a meta-analysis to address the effects of different endurance training modalities on the oxygen cost of running. A literature search on 3 databases (MEDLINE, SPORTDiscus and Web of Science) was conducted on February 28, 2019. After analysing 8028 resultant articles, studies were included if they met the following inclusion criteria: (a) studies were randomised controlled trials, (b) studies included trained runners without previous injuries (c) interventions lasted at least 6 weeks, with participants allocated to Interval (INT) or Continuous (CON) groups, and (d) oxygen cost was assessed pre- and post-training intervention. Six studies (seven trials) met the inclusion criteria and were included in the meta-analysis. This resulted in 295 participants (n = 200 INT; n = 95 CON training method). Standardised mean difference with 95% confidence intervals (CI) between INT and CON conditions and effect sizes were calculated. To assess the potential effects of moderator variables (such as, age, VO2max of participants, number of weeks of intervention) on main outcome (oxygen cost of running), subgroup analyses were performed. Comparing changes from pre- to post-intervention, oxygen cost improved to a greater extent in CON when compared to INT interventions (0.28 [95% CI 0.01, 0.54], Z = 2.05, p = 0.04, I2 = 30%). Oxygen cost improvements were larger in participants with higher VO2max (≥ 52.3 ml kg−1 min−1) (0.39 [95% CI 0.06, 0.72], Z = 2.34, p = 0.02), and in programs greater or equal to 8 weeks (0.35 [95% CI 0.03, 0.67], Z = 2.13, p = 0.03). When the total volume per week of INT was ≥ 23.2 min, there was a significant improvement favorable to CON (0.34 [95% CI 0.01, 0.61], Z = 2.02, p = 0.04). Continuous training seems, overall, a better strategy than interval training to reduce the oxygen cost in recreational endurance runners. However, oxygen cost reductions are influenced by several variables including the duration of the program, runners’ aerobic capacity, the intervals duration and the volume of interval training per week. Practitioners and coaches should construct training programs that include both endurance training methods shown to be effective in reducing the oxygen cost of running.

BACKGROUND:\ud The effect of short-term interventions using high-velocity isokinetic or plyometric exercises has not been thoroughly investigated.\ud \ud OBJECTIVE:\ud The aim of this study was to compare the effect of a lower body 3-week protocol using an isokinetic or a plyometric exercise program on strength and jump performance.\ud \ud METHODS:\ud Thirty-six non-trained men were randomly allocated to the following three groups: (i) Isokinetic only (ISO, n= 12), performed 6 sets of 10 repetitions of concentric leg extension and flexion at 300∘⋅s-1 using an isokinetic dynamometer (Biodex-System-3); (ii) Plyometric only (PLY, n= 12) performed 6 sets of 10 repetitions of vertical jump; and (iii) Control, non-training group (n= 12). A 3-week training program involving two weekly workout sessions was implemented. Pre and post intervention measurements of knee extensor and flexor maximal peak torque, total work and average power at 300∘⋅s-1 and vertical jump performance were determined.\ud \ud RESULTS:\ud Compared to baseline ISO significantly (p< 0.05) increased knee extension peak torque and average power. No other significant differences were observed at post-intervention or between groups. CONCLUSIONS: Compared to performing plyometric exercise alone, a 3-week intervention using only isokinetic training enhanced knee extensors strength. A more effective and specific neural adaptations driven by the isokinetic protocol over a short period of time could explain the observed responses.

The objective of this study was to determine the effects of high-intensity warm-ups (WUs) on performance, physiological, neuromuscular and biomechanical parameters. Three randomized cross-over 105%vVO2max time limit trials (TLimT) were performed by 11 well-trained runners following three different WU protocols. These included two experimental high-intensity variants and one control WU variant: (i) 9x20-sec level strides (105%vVO2max; 1% gradient) with 60 s of recovery (level); (ii) 6x6-sec uphill strides (105%vVO2max; 5% gradient), with the same recovery (uphill) and (iii) 7 min at 60%vVO2max as control condition (control). The uphill and level WUs resulted in a greater performance during TLimT (160.0±6.62 s and 152.64±10.88 s, respectively) compared to control WUs (144.82±6.60 s). All WU conditions reduced the energy cost (EC) of running, respiratory exchange ratio, and step frequency (SF) after the experimental and control phases of WU, while blood lactate (BLC) increased in uphill and level WUs and decreased in control WUs. Changes in kinematic variables were found without differences between WU conditions during TLimT. BLC rose at conclusion of TLimT without differences between WU conditions. Both high-intensity WUs show a longer TLimT. EC is deteriorated after the high-intensity WU exercise due to a change of substrate utilization, increase of BLC and SF. A long transient phase (18 min) is necessary to avoid impairing the performance.

The primary goal was to determine whether the achievement of finalist positions in the Junior Championship was associated with the achievement of success in the International Swimming Federation (FINA) World Championship (WC). Secondary goals included analyzing the effect of various factors (gender, age, country, etc) on swimmers' performances. Data were obtained from FINA information about the finalists from 2007 to 2015 WCs and finalists from 2006 to 2013 Junior-WCs (2400 entries). Final filtered database just included swimmers who participated in both junior and senior WCs (719 entries). A univariate general linear model (GLM) was used to examine the association between time; origin (swimmer who participated in Junior WC or not); maintenance years (number of years achieving finalist positions); country; and age, adjusting for year of competition. An ordinal logistic regression (OLR) model was used to identify predictors of achieving the top positions. The origin variable was not significant in either the GLM or the OLR. The only significant variables in the GLM were maintenance years (F4,706 = 7.689; p < .05) and year of competition (F4,706 = 23.239; p < .05). The OLR revealed a strong association (p < .001) between the position variable and maintenance years, getting better positions as you get more WCs (odds = 1.85). In conclusion, no evidence was obtained to conclude finalist position in Junior WC have influence in achieve success in FINA WC. Maintenance years in WCs have a positive impact to achieve better positions.