Which variables may affect underwater glide performance after a swimming start?

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.

Effects of Dry-Land Training Programs on Swimming Turn Performance: A Systematic Review.

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.

Swimming World Championships: Association between Success at the Junior and Senior Level for British Swimmers.

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.

The Relationship between Tactical Positioning and the Race Outcome in 800-M Running at the 2016 Olympic Games and 2017 IAAF World Championship.

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 Effects of Interval and Continuous Training on the Oxygen Cost of Running in Recreational Runners: A Systematic Review and Meta-analysis.

BACKGROUND: 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. OBJECTIVE: 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. METHODS: 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. RESULTS: 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). CONCLUSION: 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.

Comparing the Pathway to Success in European Countries Competing in the Swimming World Championships.

Purpose: This study aimed to compare the performance progression model of the European countries that participated in the World Championships (WCs) from 2006 to 2017. Data from all championships were compared between the top five (1-5) and the next five (6-10) countries on the medal table. The study also identifies the ages of peak performance in senior swimmers, the annual ratio of progression and the effect of junior performance on senior success by these groups of countries. We hypothesized that: (1) countries with swimmers achieving better performances at the Junior WCs would also be higher in the medal ranking at the Senior WCs and (2) a higher annual performance progression in their swimmers increases the chances of countries being ranked in the top 5 at the Senior World Championships. Methods: Participant's data from all Junior and Senior WCs between 2006 and 2017 were obtained from FINA. The final, filtered database included 629 swimmers after removing those participating only in the Junior WCs and selecting swimmers from the top 10 countries. One-way ANOVA, F test, and decision tree methods were used to examine differences between the top (1-5) and the next best (6-10) countries on the medal table for first participation age, annual progress, and best-time in junior and senior championships. Results: There was no difference (p = 0.492 and p = 0.97) between 1-5 and 6-10 ranked countries for best senior time and annual progression, respectively. Countries ranked in the top 5 at the Senior WCs had swimmers with faster times at the Junior WCs (p > 0.001). Decision tree analysis found that best-time at the Junior WC had the greatest explanatory capacity (94%). Conclusion: European countries with swimmers who perform best at the Junior WCs are also likely to be in the top 5 countries that win medals at the Senior WCs.

Influence of early specialization in world-ranked swimmers and general patterns to success.

OBJECTIVES: The primary goal was to examine the influence of early specialization on the performance of senior elite swimmers. Secondly, to provide information about the influence of swim style, distance, sex, status, country, years of high-level competition (YHLC) and age in swimmer's performance. DESIGN: Data was obtained from International Federation of Swimming (FINA) regarding the participants 2006-2017 of junior and senior World Championships (WCs). The final filtered database included 4076 swimmers after removing those participating only in junior WCs. METHOD: Cramer V coefficient, double and triple-entry tables were used to measure the relationship between the positions occupied in junior and senior phases. A One-Way ANOVA analysis was used to explain the variables time and rank between swimmers who participated in junior and senior WC or just in senior in all the distances and swim styles (SS). A univariate general linear model (GLM) was used to examine the association between time/rank and category (swimmers that participated previously in junior WC or not); YHLC; country; status (highest finishing position: final/semi-final/heats) and age. RESULTS: Significant differences (p < .001) were found in the GLM, with Rank as dependent variable, for all the variables. Showing that swimmers that participated previously in junior categories obtained greater results in all the interactions, except in 1500m freestyle. Significant differences (p < .001) were found between the variables position and YHLC, showing the variable position improvements as swimmers attended more WCs. CONCLUSION: Competing in junior WC has a positive influence in achieve posteriori success in FINA WC. YHLC have a positive impact to achieve better positions.

Analysis of World Championship Swimmers Using a Performance Progression Model.

PURPOSE: The primary aim was to create a performance progression model of elite competitors in the World Swimming Championships from 2006 to 2017 for all strokes and distances. Secondly, to identify the influence of annual ratios of progression, ages of peak performance and junior status on success in senior competitions. METHODS: Data regarding the participants of senior and junior World Championships (WCs) between 2006 and 2017 were obtained from FINA. The final filtered database, after removing those swimmers who just participated in junior WCs, included 4076. Statistical models were used to examine differences between the top senior swimmers (the top 30% best performances; T30) and lower level swimmers (the bottom 70% performances; L70) for minimum age (MA), progress (P) and best junior time (BJ). In order to identify the variables that contribute to reach the T30 group, a logistic regression (LR), stepwise LR and decision tree were applied. To analyze the effect of each variable separately, a simple LR (gross odds ratio) was performed. Ratio probabilities (OR) and 95% confidence intervals were calculated for each variable. RESULTS: Swimmer's BJ and P were higher in the T30 group (p < 0.000). The decision tree showed the greatest explanatory capacity for BJ, followed by P. The MA had a very low explanatory capacity and was not significant in the LR. CONCLUSION: Swimmers with exceptional junior performance times, or have a high rate of progress are more likely to be successful at the senior WCs.

The Effects of Two Different Resisted Swim Training Load Protocols on Swimming Strength and Performance.

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.

Economía de carrera y rendimiento. Esfuerzos de alta y baja intensidad en el entrenamiento y calentamiento. Revisión bibliográfica / Running economy and performance. High and low intensity efforts during training and warm-up. A bibliographic review

La economía de carrera ha crecido en importancia en la literatura científica como factor de rendimiento en corredores de fondo y medio fondo tanto de alto nivel como recreacional. Los atletas entrenados son más económicos que aquellos no entrenados, mostrando que es una variable que se mejora con el entrenamiento. Un factor clave en la selección del entrenamiento de resistencia es la intensidad del esfuerzo a realizar, principalmente caracterizado por dos métodos de entrenamientos como son el interválico y el continuo. En corredores de nivel recreacional, existe cierta controversia en relación a qué intensidades son las óptimas para mejorar la economía de carrera, recomendándose la realización de entrenamiento periodizado y exista una lógica relación entre entrenamiento de alta y baja intensidad. Recomendamos la inclusión de 2-3 sesiones semanales de entrenamiento interválico, compensado con entrenamiento continuo. En cuanto a los corredores entrenados de más nivel, el entrenamiento interválico cobra mayor importancia (intensidades cercanas al VO2 max) dado que la realización de esfuerzos de mayor intensidad provocará que sean más económicos a intensidades de competición. Intensidades de entrenamiento muy altas no conllevarán mejoras en la economía de carrera debido a que no es posible acumular suficiente volumen de entrenamiento. Por otro lado, los esfuerzos de alta intensidad previos a la competición (intensidades superiores al umbral anaeróbico), es decir, durante el calentamiento, aumentan el coste de energía (reducción de la economía de carrera) y, por lo tanto, se recomienda una amplia fase de transición entre tales esfuerzos y la competición (entre 9-20 min), para que el rendimiento no se vea perturbado. Se recomienda un aumento en el aporte científico en relación a los efectos de esfuerzos de alta intensidad durante el calentamiento, con el fin de conocer qué intensidades son más óptimas, el terreno a utilizar (llano o pendiente), o la recuperación necesaria para mejorar el rendimiento

Interest in relation to running economy has increased such as determinant of running performance in scientific literature in trained long and middle distance runners and recreational runners. Trained runners are more efficient than untrained runners, meaning it is a "trainable" parameter. A key factor during endurance training is the intensity of corresponding effort, characterized by two endurance training methods such as interval and continuous training. In recreational runners, there is some controversy about which intensities are optimal in order to improve running economy, thus, periodized endurance training with a logical relationship between high and low-intensity training is recommended. We recommend the inclusion of 2-3 session per week of interval training, compensated with continuous training. Regarding to trained runners, interval training (at intensities close to VO2 max) will be more important because of the need to be more economical at competitive intensities. Very high training intensities would not lead improvements in running economy due to it is not posible to accumulate enough training volumen during the training period. Conversely, the high-intensity efforts prior to competition (intensities above anaerobic threshold), during a warm-up protocol, increase the energy cost (reduce the running economy) and therefore, it is recommended a long transient phase (9-20 min) before to competition so as not to disturb the subsequent performance. An increase of scientific studies regarding the effects of high-intensity efforts during a warm-up protocol is needed in order to know the optimal intensities, flat or uphill ground, or the adequate recovery to improve the subsequent performance

Effects of High-intensity Warm-ups on Running Performance.

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.