rss_2.0Sports and Recreation FeedSciendo RSS Feed for Sports and Recreation and Recreation Feed Team Sport Training With Multi-Objective Evolutionary Computation<abstract> <title style='display:none'>Abstract</title> <p>This research introduces a new novel method for mathematically optimizing team sport training models to enhance two measures of athletic performance using an evolutionary computation based approach. A common training load model, consisting of daily training load prescriptions, was optimized using an evolutionary multi-objective algorithm to produce improvements in the mean match-day running intensity across a competitive season. The optimized training model was then compared to real-world observed training and performance data to assess the potential improvements in performance that could be achieved. The results demonstrated that it is possible to increase and maintain a stable level of match-day running performance across a competitive season whilst adhering to model-based and real-world constraints, using an intelligently optimized training design compared a to standard human design, across multiple performance criteria (BF+0 = 5651, BF+0 = 11803). This work demonstrates the value of evolutionary algorithms to design and optimize team sport training models and provides support staff with an effective decision support system to plan and prescribe optimal strategies to enhance in-season athlete performance.</p> </abstract>ARTICLE2021-09-25T00:00:00.000+00:00Comparing bottom-up and top-down ratings for individual soccer players<abstract> <title style='display:none'>Abstract</title> <p>Correctly assessing the contributions of an individual player in a team sport is challenging. However, an ability to better evaluate each player can translate into improved team performance, through better recruitment or team selection decisions. Two main ideas have emerged for using data to evaluate players: Top-down ratings observe the performance of the team as a whole and then distribute credit for this performance onto the players involved. Bottom-up ratings assign a value to each action performed, and then evaluate a player based on the sum of values for actions performed by that player. This paper compares a variant of plus-minus ratings, which is a top-down rating, and a bottom-up rating based on valuing actions by estimating probabilities. The reliability of ratings is measured by whether similar ratings are produced when using different data sets, while the validity of ratings is evaluated through the quality of match outcome forecasts generated when the ratings are used as predictor variables. The results indicate that the plus-minus ratings perform better than the bottom-up ratings with respect to the reliability and validity measures chosen and that plus-minus ratings have certain advantages that may be difficult to replicate in bottom-up ratings.</p> </abstract>ARTICLE2021-05-08T00:00:00.000+00:00Can Elite Australian Football Player’s Game Performance Be Predicted?<abstract> <title style='display:none'>Abstract</title> <p>In elite Australian football (AF) many studies have investigated individual player performance using a variety of outcomes (e.g. team selection, game running, game rating etc.), however, none have attempted to predict a player’s performance using combinations of pre-game factors. Therefore, our aim was to investigate the ability of commonly reported individual player and team characteristics to predict individual Australian Football League (AFL) player performance, as measured through the official AFL player rating (AFLPR) (Champion Data). A total of 158 variables were derived for players (n = 64) from one AFL team using data collected during the 2014-2019 AFL seasons. Various machine learning models were trained (cross-validation) on the 2014-2018 seasons, with the 2019 season used as an independent test set. Model performance, assessed using root mean square error (RMSE), varied (4.69-5.03 test set RMSE) but was generally poor when compared to a singular variable prediction (AFLPR pre-game rating: 4.72 test set RMSE). Variation in model performance (range RMSE: 0.14 excusing worst model) was low, indicating different approaches produced similar results, however, glmnet models were marginally superior (4.69 RMSE test set). This research highlights the limited utility of currently collected pre-game variables to predict week-to-week game performance more accurately than simple singular variable baseline models.</p> </abstract>ARTICLE2021-08-10T00:00:00.000+00:00Strictness vs. flexibility: Simulation-based recognition of strategies and its success in soccer<abstract> <title style='display:none'>Abstract</title> <p>Introduction: Recognition and optimization of strategies in sport games is difficult in particular in case of team games, where a number of players are acting “independently” of each other. One way to improve the situation is to cluster the teams into a small number of tactical groups and to analyze the interaction of those groups. The aim of the study is the evaluation of the applicability of SOCCER© simulation in professional soccer by analyzing and simulation of the tactical group interaction.</p> <p>Methods: The players’ positions of tactical groups in soccer can be mapped to formation-patterns and then reflect strategic behaviour and interaction. Based on this information, Monte Carlo-Simulation allows for generating strategies, which – at least from the mathematical point of view – are optimal. In practice, behaviour can be orientated in those optimal strategies but normally is changing depending on the opponent team’s activities. Analyzing the game under the aspect of such simulated strategies revealed how strictly resp. flexible a team follows resp. varies strategic patterns.</p> <p>Approach: A Simulation- and Validation-Study on the basis of 40 position data sets of the 2014/15 German Bundesliga has been conducted to analyze and to optimize such strategic team behaviour in professional soccer.</p> <p>Results: The Validation-Study demonstrated the applicability of our tactical model. The results of the Simulation-Study revealed that offensive player groups need less tactical strictness in order to gain successful ball possession whereas defensive player groups need tactical strictness to do so.</p> <p>Conclusion: The strategic behaviour could be recognized and served as basis for optimization analysis: offensive players should play with a more flexible tactical orientation to stay in possession of the ball, whereas defensive players should play with a more planned orientation in order to be successful. The strategic behaviour of tactical groups can be recognized and optimized using Monte Carlo-based analysis, proposing a new and innovative approach to quantify tactical performance in soccer.</p> </abstract>ARTICLE2021-05-08T00:00:00.000+00:00Comparison of the Evaluation of Performance Preconditions in Tennis with the Use of Equal and Expertly Judged Criteria Weights<abstract> <title style='display:none'>Abstract</title> <p>Tennis performance is influenced by various factors, among which physical performance factors play an important role. The aim of the study was an analysis of possibilities of the use of Saaty’s method for assessing the level of performance prerequisites and comparing the results obtained using equal weights and various weights. The research on Czech female players (U12; n = 211) was based on the results of the TENDIAG1 test battery (9 items) and the results were processed by FuzzME software and relevant statistical methods (correlation coefficient r, Student´s t-test, effect size index d). The results of Saaty’s method show that the most important athletic performance criteria for tennis coaches are the leg reaction time and the running speed, while the least important are endurance and strength. The evaluation using various criteria weights offers a finer scale for assessing athletes’ performance prerequisites despite the proven high degree of association between the results obtained with equal and various weights and the insignificant difference of mean values. The results have shown possibilities for the use of a fuzzy approach in sports practice and motivate further research towards broadening the structure or the number of evaluation criteria.</p> </abstract>ARTICLE2021-08-10T00:00:00.000+00:00Sports Information Systems: A systematic review<abstract> <title style='display:none'>Abstract</title> <p>Many professional sport organizations are currently in the process of finding or already using <italic>sports information systems (SIS)</italic> to integrate data from different information and measurement systems. The problem is that requirements are very heterogeneous. That is why no consistent definition of <italic>SIS</italic> and their categories exist, and it is often not clear which fields and functions <italic>SIS</italic> must cover. This work aims to provide a structured comparison of commercial <italic>SIS</italic> available on the market to provide an overview of the relevant features and characterize categories. Following PRISMA guidelines, a systematic search for relevant <italic>SIS</italic> providers was conducted. A catalog of 164 review items was created to define relevant features of <italic>SIS</italic> and to conduct semi-standardized interviews with product representatives. Overall 36 eligible <italic>SIS</italic> from 11 countries were identified and 21 of them were interviewed. The analysis of the interviews has shown that there are features that are present in all <italic>SIS</italic>, whereas others differ or are generally less represented. As a result, different <italic>SIS</italic> categories have been defined. The study suggests a more differentiated categorization of <italic>SIS</italic> is necessary and terms need to be defined more precisely. This review should be considered when companies designing <italic>SIS</italic> or sport organizations select <italic>SIS</italic>.</p> </abstract>ARTICLE2021-05-08T00:00:00.000+00:00Validation of Velocity Measuring Devices in Velocity Based Strength Training<abstract> <title style='display:none'>Abstract</title> <p>To control and monitor strength training with a barbell various systems are on the consumer market. They provide the user with information regarding velocity, acceleration and trajectory of the barbell. Some systems additionally calculate the 1-repetition-maximum (1RM) of exercises and use it to suggest individual intensities for future training. Three systems were tested: GymAware, PUSH Band 2.0 and Vmaxpro. The GymAware system bases on linear position transducers, PUSH Band 2.0 and Vmaxpro base on inertial measurement units. The aim of this paper was to determine the accuracy of the three systems with regard to the determination of the average velocity of each repetition of three barbell strength exercises (squat, barbell rowing, deadlift). The velocity data of the three systems were compared to a Vicon system using linear regression analyses and Bland-Altman-diagrams.</p> <p>In the linear regression analyses the smallest coefficient of determination (R<sup>2</sup>.) in each exercise can be observed for PUSH Band 2.0. In the Bland-Altman diagrams the mean value of the differences in the average velocities is near zero for all systems and all exercises. PUSH Band 2.0 has the largest differences between the Limits of Agreement. For GymAware and Vmaxpro these differences are comparable.</p> </abstract>ARTICLE2021-09-25T00:00:00.000+00:00The Relationship Between Performance and Asymmetries in Different Multidirectional Sprint Tests in Soccer Players<abstract> <title style='display:none'>Abstract</title> <p>Practitioners usually include change of direction (COD) and linear speed measurements in the testing batteries of soccer players; however, despite being a commonly occurring action, curve sprint (CS) ability is rarely assessed in soccer. The aims of this study were to analyze the association between linear sprint, CS, and COD speed performances, and compare the association and direction of asymmetries between these skills. Thirty-three male soccer players performed linear sprint (17 m), CS (17 m), and COD-90<sup>⍛</sup> speed tests (COD [8.5 + 8.5 m]). Our main findings were (a) a large relationship between linear and multidirectional tasks (COD-90<sup>⍛</sup> and CS tests) (r = from 0.6 to 0.64, p &lt; 0.05), (b) a moderate relationship between CS and COD-90<sup>⍛</sup> tests (r = from 0.33 to 0.41, p &lt; 0.05), with a certain opposite tendency (higher relationships between opposing directions [Curve<sub>LEFT</sub> - COD<sub>RIGHT</sub>; r = 0.41] than between equal directions [Curve<sub>LEFT</sub> – COD<sub>LEFT</sub>; r = 0.33]), and (c) no relationship (p &gt; 0.05) between COD and CS asymmetries, with opposing directional dominance in ~70% of players (e.g., curve left and COD right dominance). These results indicate that performance in linear sprints is strongly related to performance in multidirectional trajectories, whereas CS and COD-90<sup>⍛</sup> seem to be more independent actions. Additionally, the direction of asymmetry or dominance is generally opposite between the non-linear tasks measured.</p></abstract>ARTICLE2021-07-28T00:00:00.000+00:00Prediction of Match Outcomes with Multivariate Statistical Methods for the Group Stage in the UEFA Champions League<abstract><title style='display:none'>Abstract</title><p>The aim of this study was to analyse the win, draw, and loss outcomes of soccer matches with situational variables and performance indicators. Data from group stage matches spanning the ten years between the 2010/2011 and 2019/2020 seasons in the European Champions League, were used. One-way analysis of variance (ANOVA) and Tukey HSD (honestly significant difference) tests indicated performance indicators which affected the outcome of matches. K-mean clustering, with statistically significant variables, categorized the quality of the opposition into three clusters: weak, balanced, and strong. Multidimensional scaling (MDS) and decision tree analysis were applied to each of these clusters, highlighting that performance indicators of the teams differed according to the quality of their opponent. Furthermore, according to the decision tree analysis, certain performance indicators, including scoring first and shots on target, increased the chances of winning regardless of the quality of the opposition. Finally, particular performance indicators increased the chance of winning, while others decreased this, in accordance with the quality of the opposition. These findings can help coaches develop different strategies, before or during the match, based on the quality of opponents, situational variables, and performance indicators.</p></abstract>ARTICLE2021-07-28T00:00:00.000+00:00Does the Intron 7 Gene Variant (rs4253778) Influence Performance in Power/Strength‐Oriented Athletes? A Case‐Control Replication Study in three Cohorts of European Gymnasts<abstract> <title style='display:none'>Abstract</title> <p>Athletic ability is influenced by several exogenous and endogenous factors including genetic component. Hundreds of gene variants have been proposed as potential genetic markers associated with fitness-related phenotypes as well as elite-level athletic performance. Among others, variants within the PPARA gene that code for the peroxisome proliferator activated receptor α are of potential interest. The main goal of the present study was to determine PPARA (G/C, rs4253778) genotype distribution among a group of Polish, Lithuanian and Italian international level male gymnasts and to compare our findings with those of previous research on the frequency of the PPARA intron 7 C allele/CC genotype in power/strength-oriented athletes. A total of 464 male subjects (147 gymnasts and 317 controls) from Poland (n = 203), Italy (n = 146) and Lithuania (n = 107) participated in the study. No statistically significant differences were found in any of the analyzed cohorts. However, a significantly higher frequency of the CC genotype of the PPARA rs4253778 polymorphism was observed when all gymnasts were pooled and compared with pooled control using a recessive model of inheritance (OR = 3.33, 95% CI = 1.18-10, p = 0.022). It is important to know that we investigated a relatively small sample of male European gymnasts and our results are limited only to male participants. Thus, it is necessary to validate our results in larger cohorts of athletes of different ethnicities and also in female gymnasts to find out whether there is a gender effect.</p></abstract>ARTICLE2021-07-28T00:00:00.000+00:00Hydration to Maximize Performance And Recovery: Knowledge, Attitudes, and Behaviors Among Collegiate Track and Field Throwers<abstract> <title style='display:none'>Abstract</title> <p>Hydration plays an important role in performance, injury prevention, and recovery for athletes engaged in competitive sports. Therefore, it is important that strength and conditioning coaches understand an athlete’s hydration needs to prevent illness and enhance performance. The purpose of this study was to identify hydration knowledge, attitudes, and behaviors of collegiate track and field throwers, as well as identify barriers to hydration and sources of nutritional information. The Rehydration and Refueling in Collegiate Track and Field Throwers Survey was sent to 271 track and field thrower coaches with a request to forward the email to current track and field throwers. Pearson correlation coefficients were calculated regarding knowledge, attitude, and behavior scores among the participants in this sample. Differences among response patterns were assessed via Chi-square analysis. Alpha level was set at p = .05. Results demonstrated that 97.3% (n = 287) of respondents knew that dehydration would decrease performance, but 50.5% (n = 149) erroneously believed thirst was the best indicator of dehydration. Chi-square analysis demonstrated a significant difference in reported values between participants who intended to eat a performance-enhancing diet and those who consumed less fluid than recomended values (207 – 295 m)l in the 2-3 hours prior to competition (χ2 = 10.87, p &lt; .05). Pearson correlation coefficients demonstrated a large association between knowledge and behavior (r = .70, p &lt; .05), a medium association between knowledge and attitude (r = .41, p &lt; .05), and a small association between attitude and behavior (r = .21, p &lt; .05). This suggests that strength and conditioning coaches and health staff need to educate and monitor hydration behaviors among collegiate track and field throwers to optimize performance.</p></abstract>ARTICLE2021-07-28T00:00:00.000+00:00Average Game Physical Demands and the Most Demanding Scenarios of Basketball Competition in Various Age Groups<abstract><title style='display:none'>Abstract</title><p>The purpose of this study was to compare average physical demands and the most demanding 60-s scenarios of basketball match-play between five different age groups. Sixty-four male basketball players from five different age groups were monitored across eight regular-season home games. Physical demands were examined using a local positioning system and included total distance covered, distance &gt;18 km·h<sup>-1</sup>, the number of accelerations (≥2 m·s<sup>-2</sup>) and decelerations (≤-2 m·s<sup>-2</sup>). All four game performance variables increased significantly (58.4 - 639.2%) when calculated with rolling average techniques in comparison to average physical demand values. Furthermore, the current investigation found that while Under-12 presented the highest result in relative total distance covered (p &lt; .001; effect size = 0.58-2.01), they also showed the lowest values in the most demanding scenarios of match play and small-to-moderate effect sizes compared with their older counterparts. Both average physical demands and the most demanding scenarios presented an increasing tendency with age when distance &gt;18 km·h<sup>-1</sup> in basketball players was assessed. More specifically, the Under-12 age group achieved the lowest values and showed significant differences with the other four teams in both game analysis techniques (p &lt; .001; effect size = 0.53 - 1.32). In conclusion, average game demands are shown to remarkably underestimate the most demanding scenarios of basketball match-play, and there are multiple significant differences between particular age groups.</p></abstract>ARTICLE2021-07-28T00:00:00.000+00:00Long-Term Trend Analysis of Playing Styles in the Chinese Soccer Super League<abstract><title style='display:none'>Abstract</title><p>The aim of this study was to identify playing styles adopted by teams in the Chinese Soccer Super League (CSL) and to investigate their evolution across a 6-season period. Data were collected from 1,429 CSL matches from 2012 to 2017 seasons using the Amisco system. Seventeen technical performance-related indicators and eleven physical performance-related indicators were included in the factor analysis (PCA: principal components analysis) in order to group them into performance factors (styles of play). Seven factors were obtained (eigenvalues greater than 1) and explained 74.44% of the total variance. Multivariate analyses of covariance (MANCOVA) were used to check differences among seven styles of play (team’s ranking was used as a covariate) during the six seasons under study. The main findings showed that Factor 1 (high intensity play) and factor 3 (offensive actions) of CSL soccer increased substantially along the seasons. Coaches and sports scientists should take into consideration these performance trends when preparing training and controlling for matches</p></abstract>ARTICLE2021-07-28T00:00:00.000+00:00Anaerobic Capacity is Associated with Metabolic Contribution and Mechanical Output Measured During the Wingate Test<abstract> <title style='display:none'>Abstract</title> <p>The study aimed to investigate the relationship between anaerobic capacity, mechanical and anaerobic contribution during the 30-s Wingate Anaerobic Test (30sWAnT). After familiarization, fifteen, male recreational mountain biking practitioners underwent the following sequence of tests: 1) a graded exercise test to determine maximal oxygen uptake and associated intensity <inline-formula><alternatives><inline-graphic xmlns:xlink="" xlink:href="graphic/j_hukin-2021-0063_eq_001.png"/><mml:math xmlns:mml=""> <mml:mfenced open="(" close=")"> <mml:mrow> <mml:mi>i</mml:mi> <mml:mrow class="MJX-TeXAtom-ORD"> <mml:mover> <mml:mi>V</mml:mi> <mml:mo>˙<!-- ˙ --></mml:mo> </mml:mover> </mml:mrow> <mml:msub> <mml:mi>O</mml:mi> <mml:mrow class="MJX-TeXAtom-ORD"> <mml:mn>2</mml:mn> <mml:mi>m</mml:mi> <mml:mi>a</mml:mi> <mml:mi>x</mml:mi> </mml:mrow> </mml:msub> </mml:mrow> </mml:mfenced> <mml:mo>;</mml:mo> </mml:math><tex-math> $\left(i \dot{V} O_{2 m a x}\right);$</tex-math></alternatives></inline-formula> 2 and 3) supramaximal exhaustive effort at 115% of iVO<sub>2max</sub> and 30sWAnT, performed randomly. The glycolytic and phosphagen pathways measured during the supramaximal effort were significantly correlated with peak power (r = 0.85; p &lt; 0.01 and r = 0.57; p = 0.02, respectively), mean power (r = 0.78; p &lt; 0.01 and r = 0.69; p &lt; 0.01, respectively), and total work (r = 0.78; p &lt; 0.01 and r = 0.69; p&lt; 0.02, respectively) measured during the 30sWAnT. A significant correlation was also found between anaerobic capacity and peak power (r = 0.88; p &lt; 0.01), mean power (r = 0.89; p &lt; 0.01), and total work (r = 0.89; p &lt; 0.01). Additionally, anaerobic capacity estimated during the supramaximal effort and the anaerobic contribution measured during the 30sWAnT were not different (p = 0.44) and presented significant good reliability and association (ICC = 0.84; p = 0.001) and good agreement, evidenced by the mean of differences and 95% limits of agreement near to zero (mean bias = 0.11). The results suggest that glycolytic and phosphagen capacity were associated with mechanical performance in the 30sWAnT. In addition, anaerobic contribution during the 30sWAnT seems to be valid for estimating anaerobic capacity in recreational mountain bike cyclists, as well as to estimate the glycolytic and phosphagen contributions.</p></abstract>ARTICLE2021-07-28T00:00:00.000+00:00The Fifth Metatarsal Bone Fracture In Athletes ‐ Modalities of Treatment Related to Agility In Soccer Players<abstract> <title style='display:none'>Abstract</title> <p>The 5<sup>th</sup> metatarsal fracture is a common foot fracture which could exclude a player from competition for several months and significantly affect his or her career. This manuscript presents the treatment and rehabilitation of professional soccer players who had acute fractures of the 5th metatarsal bone and a cannulated screw fixation. The main purpose of the analysis was to determine the minimum time necessary for a permanent return to the sport after a 5<sup>th</sup> metatarsal fracture among professional soccer players. We followed the surgical and rehabilitation path of 21 professional soccer players from the Polish League (I<sup>st</sup> and II<sup>nd</sup> divisions) who suffered from the 5<sup>th</sup> metatarsal bone fracture. All players underwent standard percutaneous internal fixation with the use of cannulated screws. The total inability to play lasted for 9.2 (± 1.86) weeks among players treated only surgically (n = 10), 17.5 (± 2.5) weeks in the conservative and later surgery group, excluding players with nonunion (n = 6), and 24.5 (± 10.5) weeks for nonunion and switch treatment (n = 4) players. Prompt fracture stabilization surgery is recommended for athletes, enabling the implementation of an aggressive rehabilitation protocol as soon as possible. Early limb loading after surgery (from week 2) does not delay fracture healing or hinder the bone union, thus rehabilitation plays a crucial role in shortening the time of RTP (return to play) and is obligatory for each athlete who undergoes surgical treatment.</p></abstract>ARTICLE2021-07-28T00:00:00.000+00:00The Influence of Sprint Mechanical Properties on Change of Direction in Female Futsal Players<abstract><title style='display:none'>Abstract</title><p>The aim of the present study was to analyze the association of the sprint force-velocity profile [Hzt FV profile] variables with change of direction [COD] performance in female futsal players. Twelve female futsal players (age: 19.83 ± 4.2 years; body height: 160.75 ± 8.37 cm; body mass: 57.64 ± 8.3 kg) volunteered to be evaluated in the following assessments: Hzt FV profile, 505 test, modified 505 test [M505test] and V-cut test. The Spearman’s correlation coefficient [r<sub>s</sub>] (p &lt; 0.05) was used to determine the relationship of the mechanical variables of the sprint (maximum power output [P<sub>max</sub>], maximum horizontal force production [F<sub>0</sub>] and maximum velocity [V<sub>0</sub>]) with COD performance. V<sub>0</sub> showed a very large significant association with the 505 test (r<sub>s</sub> = -0.767; 90% CI: (-0.92 to -0.43); p &lt; 0.01) and a large association with the V-cut test (r<sub>s</sub> = -0.641; 90% CI: (-0.86 to -0.21); p &lt; 0.05), whereas P<sub>max</sub> was strongly associated with results of the 505 test (r<sub>s</sub> = -0.821; 90% CI: (-0.94 to -0.55); p &lt; 0.01) and largely associated with the V-cut test results (r<sub>s</sub> = -0.596; 90% CI: (-0.84 to -0.14); p &lt; 0.05). In conclusion, maximal power and velocity output during sprinting are determinant factors to successful COD in 180º and 45º cuts, thus, the Hzt FV profile should be assessed in female futsal players to better understand the influence of sprint mechanical properties on COD performance and prescribe individualized training programs</p></abstract>ARTICLE2021-07-28T00:00:00.000+00:00The Coaches’ Efficacy Expectations of Youth Soccer Players with Different Maturity Status and Physical Performance<abstract> <title style='display:none'>Abstract</title> <p>This study aimed to report possible anthropometrical and physical performance differences between youth soccer players with different maturity status and to report the coaches’ expectations, hypothesizing that coaches would expect more from players with advanced maturity. One hundred twenty-two (122) players completed a physical performance battery. Their maturity status was estimated and the coaches’ efficacy expectations (CEEs) were assessed. Players with advanced maturation had better physical performance (F = 26.5-73.4; p &lt; 0.01) and their CEEs for strength-related tasks were different according to the maturity status (F = 8.3-10.9; p &lt; 0.01), but not for speed-related tests, nor for their general ability to play soccer. Normalized data showed significant differences between physical performance tests and their respective CEEs within each maturity group, especially in the Post-PHV group. This study confirms the physical advantages of players with advanced maturity while it shows controversial results of how maturation affects the coaches’ perceptions and, indirectly, the coaches’ identification and selection of talented players.</p> </abstract>ARTICLE2021-07-28T00:00:00.000+00:00Post-Eccentric Flywheel Underwater Undulatory Swimming Potentiation in Competitive Swimmers<abstract> <title style='display:none'>Abstract</title> <p>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<sup>®</sup>. 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 &lt; 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 &lt; 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.</p></abstract>ARTICLE2021-07-28T00:00:00.000+00:00Peak Running Intensities in Field Hockey - a Positional Analysis<abstract> <title style='display:none'>Abstract</title> <p>The aim of this study was to investigate the positional mean peak running periods during a field hockey match using a moving average method. The secondary aim was to investigate how the peak periods changed between quarters and playing positions. The moving average method was used to analyse the data because of the nature of field hockey, which has natural fluctuations of high and low intensity periods of play. The time periods included periods from 1 to 10 minutes. The level of significance for results was set at p ≤ 0.05. The study found that forwards had a peak running intensity of 194 ± 24.2 m·min<sup>-1</sup>, midfielders 189 ± 11.9 m·min<sup>-1</sup>, and defenders 182.6 ± 17.9 m·min<sup>-1</sup>. These results showed that forwards had the highest maximum running speed, with defenders having the lowest one (p = 0.0025). Additionally, running output started to plateau after 7/8-min periods for each of the three positions. Forwards did not show any statistically significant changes across the four quarters. Midfielders showed effect sizes ranging from &gt;0.6 to &gt;2.0 (moderate, large and very large) significance when comparing the first three quarters to the fourth one. Defenders showed &gt;0.6 to &lt;2.0 (moderate to large) effect sizes to occur when comparing the first and second quarter to the fourth. There are three main practical implications from the results of this study: 1) the creation of conditioning drills, 2) substitution patterns, and 3) knowledge to be able to plan and train at or above peak match demands.</p></abstract>ARTICLE2021-07-28T00:00:00.000+00:00Effects of a Neuromuscular Warm-Up Program in Youth Female Soccer Players<abstract> <title style='display:none'>Abstract</title> <p>The protective effects of different warm-up injury prevention routines in youth female soccer players have been demonstrated in the literature, however, there is a paucity of information regarding the effects that these kinds of programs have on soccer-specific physical performance variables. The purpose of this study was to assess the effectiveness of a 12-week neuromuscular warm-up program on physical performance in youth female soccer players. Players (age: 13.94 ± 0.82 years) were divided into two groups. One group performed a neuromuscular activation program (n = 21) twice per week whereas the other group (control, n = 17) continued with their habitual warm-up routine for the same duration. Both groups of players performed strength, jumping and balance tests before and after the intervention period. Substantially greater improvements were detected in the mean velocity for the squat (p &lt; 0.001; Effect Size = 0.95) and the hip thrust (p &lt; 0.001; Effect Size = 0.51) in the experimental group in comparison to the control group. In addition, after the intervention period players in the experimental group showed an increase in the jumping height in the unloaded double-leg and single-leg counter-movement jumps (p = 0.003-0.012; Effect Size = 0.42-0.46). The results of this study provide evidence that a 12-week neuromuscular warm-up program can be effective to improve different physical performance variables in youth female soccer players.</p> </abstract>ARTICLE2021-07-28T00:00:00.000+00:00en-us-1