Search

Abstract The aim of this study is to analyse the relationship between sport modalities practiced, physical fitness, body composition, and healthy habits in an active young population, using a statistical model for prediction. A total of 2255 (1528 boys and 727 girls) children and adolescents aged 6–17 years old who were involved in extracurricular sports from rural areas of Spain participated. Physical fitness was assessed through validated field test and, body composition was determinated using bioelectrical impedance analysis. Adherence to the Mediterranean diet was assessed by KIDMED questionnaire. The general sport variable was significant in VO2max when comparing the invasion and combat modalities to the reference level (court/net). The sex and age variables revealed significant differences in all physical fitness and body composition parameters. Health parameters, such as hours of additional practice, adherence to the Mediterranean diet, and previous experience, showed significant differences. The study concludes that the sport modality variables of training, sex, age, and maturational period have an impact on body composition and fitness parameters in this population. Therefore, by focusing on factors associated with lower values in health indicators, we can prevent health problems during adulthood, such as cardiorespiratory deficits.

The aim was to analyse the consequences of a congested schedule (due to the COVID-19 lockdown) on creatine kinase (CK) in elite football players using GPS tracking technology. A total of 17 elite football players were monitored in training and competition with a global positioning system. Variables including total distance, high-intensity distance, and distance acceleration and deceleration were analysed. Different measurements of serum creatine kinase (CK) concentration were performed on match day (MD) and at 24 h (MD+1), 48 h (MD+2), and 72 h (MD+3) after each match to study the muscle damage of each individual player caused during the match. The results showed a significant increase in physical demands in training (in relative terms regarding the match) at MD+3 compared to MD+1 and MD+2. Furthermore, at +72 h, CK decreases to a value almost the same as that before MD. On the other hand, the players with lower demands for high-intensity actions in the match showed a higher reduction in the concentration of CK at MD+3 compared to MD+1 and MD+2 (p < 0.05). It became evident that players with high-intensity demand and a high number of accelerations and decelerations need more time to assimilate the match load and can remain in a state of muscle fatigue for up to 3 days. In addition, a congested schedule can lead to a state of chronic fatigue in elite football players, limiting physical performance and possibly increasing the potential risk of injury for football players.

Abstract The demanding nature of elite football requires players to be closely monitored to ensure optimal performance and minimize injury risk. This study aimed to evaluate the relationship between physical demands, skin temperature, and well-being status in 30 elite football players over a 12-week competitive period. Thermography assessments, weekly Well-being questionnaires, and daily training and match load recordings were used to gather data. Results indicated that along the microcycles there was a decrease in high-intensity accelerations and decelerations distance completed, while maintaining other high-intensity actions. Furthermore, it was found that high-intensity movements contribute to the generation of thermal asymmetries in the thighs; the adductor thermal asymmetry showed a positive relationship with stress and muscle soreness, the knee thermal asymmetry had a positive relationship with fatigue and a negative relationship with rest and quality of rest, and finally the hamstrings muscles exhibited significant differences between the thermal asymmetry groups, with the high asymmetry completing less high intensity actions than the low asymmetry group. In conclusion, this study highlights the interconnections between physical demands, skin temperature, and well-being in elite football players and provides valuable insights for coaches and trainers in their efforts to optimize performance and health.

Abstract Background Although the scientific literature has previously described the impact of worksite programs based on physical activity (WPPAs) on employees’ productivity and health in different contexts, the effect of these programs has not been analyzed based on the characteristics or modalities of physical activity (PA) performed (e.g., aerobic exercise, strength training, flexibility). In addition, studies on WPPAs usually report health and productivity outcomes separately, not integrated into a single study. Knowing the health and economic-related impacts of a WPPAs could provide useful information for stakeholders and policy development. Objective The purpose of this review was as follows: (1) to analyze the effect of different modalities of WPPAs on employees’ productivity and health and (2) to investigate the economic impact of WPPAs. Methods This systematic review is registered in PROSPERO (CRD42021230626) and complies with PRISMA guidelines. Only randomized controlled trials from 1997 to March 2021 were included. Two reviewers independently screened abstracts and full texts for study eligibility, extracted the data, and performed a quality assessment using the Cochrane Collaboration Risk-of-Bias Tool for randomized trials. Population, instruments, comparison, and outcome (PICO) elements were used to define eligibility criteria. Eight-hundred sixty relevant studies were found through electronic searches in PubMed, Web of Science, Medline, Scopus, and SPORTDiscus databases. Once the eligibility criteria were applied, a total of 16 papers were included. Results Workability was the productivity variable most positively impacted by WPPAs. Cardiorespiratory fitness, muscle strength, and musculoskeletal symptoms health variables improved in all the studies included. It was not possible to fully examine the effectiveness of each exercise modality because of the heterogeneity in methodology, duration, and working population. Finally, cost-effectiveness could not be analyzed because this information was not reported in most studies. Conclusion All types of WPPAs analyzed improved workers’ productivity and health. However, the heterogeneity of WPPAs does not allow to identify which modality is more effective.

Abstract The aim of this study was to analyse the differences in the A–S profile of elite football players induced by playing position and the microcycle day. Players belonged to a second division club in the Spanish La Liga competition. They were classified into five playing positions: central defenders (CD), full backs (FB), midfielders (MF), wide midfielders (WMF) and forwards (FW). Microcycle days were categorised according to the days until matchday (MD, MD-1, MD-2, MD-3, MD-4 and MD-5). Data was collected along six microcycles, including one match per microcycle. The variables analysed were: maximal theoretical acceleration (A0), maximal theoretical speed (S0), maximal acceleration (ACCmax), maximal speed (Smax) and A–S slope (ASslope). Significant differences were found within positions and microcycle day for all variables (p

The aim of this study is to analyze the worst-case scenarios of professional futsal referees during the first and second half of official matches in the Spanish Futsal Cup using a Local Positioning System (LPS) for monitoring their movement patterns. Eight professional futsal referees (40 ± 3.43 years; 1.80 ± 0.03 m; 72.84 ± 4.01 kg) participated in the study. The external load (total distance, high-speed running distance and efforts, sprint distance and efforts, and accelerations and decelerations distances) of the referees was monitored and collected using an LPS. The results revealed significant differences in the worst-case scenarios of the futsal referees during the match according to the time window analyzed (p < 0.05). The longest time windows (120 s, 180 s, and 300 s) showed lower relative total distances in the worst-case scenarios (p < 0.05). The high-speed running distances were significatively higher in the first half for the 120 s (+2.65 m·min−1; ES: 1.25), 180 s (+1.55 m·min−1; ES: 1.28), and 300 s (+0.95 m·min−1; ES: 1.14) time windows (p < 0.05). No differences were found between the first and second half for the high-intensity deceleration distance (p > 0.05). These results will serve to prepare the referees in the best conditions for the competition and adapt the training plans to the worst-case scenarios.

To investigate the effect of COVID-19 lockdown on match-play metrics in professional football referees during official matches of the Spanish professional leagues. Forty-two professional football referees from the First (n = 20) and Second Division (n = 22) were monitored during 564 official games using Global Positioning System (GPS) technology. Data of matches before lockdown were compared to matches after resumption of the competition. Compared to pre-lockdown, in the referees of the First Division there was a decrease in the total running distance and the distance covered at all speed thresholds > 6 km ·h-1 after lockdown (P

Abstract This study aimed to analyse the influence of the FIFA Quality PRO certification of artificial turf pitches on the physical, physiological performance and muscle damage in soccer players. Fifteen healthy male players (21.2 ± 1.4 years; 178.2 ± 4.3 cm; 79.1 ± 8.3 kg) from a university football team were selected to participate in the research. Mechanical properties related to surface–player interaction were assessed on the two surfaces selected for this study. A randomized design was used and the players performed the Ball-sport Endurance and Sprint Test (BEAST90) on the different artificial turf fields. Average time of the 20 m sprints was longer on the FIFA Quality Pro surface than on the non-certified pitch (+ 0.13 s; p 0.05; CI 95% 66.54 to 326.61; ES: 1.645) were evidenced in the non-certified pitch surface. In response to a simulated match protocol, markers of post-exercise muscle damage may be reduced on accredited artificial turf fields. These insights can provide the opportunity to maximize the efficiency of training sessions and reduce the risk of injury during the season.

The aim of this study was to describe and analyse the effects of a 12-week football programme on body composition (fat mass, muscle mass, and bone mass) in children compared to a sedentary lifestyle, as well as the physical demands and loads required in training and matches in young football players (U10–U12). Forty children were included, divided into two groups: a football group (FG; n = 20) and a control group (CG; n = 20). Body composition was analysed using DXA and physical demands were analysed using GPS, with a total of 504 observations. Total bone mineral content (BMC) was significantly increased in FG-U12 (p = 0.025) after training. Total bone mineral density (BMD) was increased after the 12 weeks in FG-U10 (p = 0.001) and FG-U12 (p = 0.002). Leg BMC in FG-U10 (p < 0.05; 2.2 to 7.1 g) and FG-U12 (p < 0.05; 2.0 to 17.0 g) was increased after 12 weeks. VO2 max after training was significantly improved in FG-U10 (p < 0.05; ES: 1.7 to 5.2 mL/kg/min) and FG-U12 (p < 0.05; 0.3 to 3.8 mL/kg/min). Among U10s, midfielders covered greater distances and had higher intensity accelerations (p < 0.05; ES: 1.05 to 2.00) than forwards and defenders. Among U12s, midfielders in matches covered greater distances and at higher intensity than in training (p < 0.05; ES: 1.05 to 2.39). Football practice produces benefits in total and lower limb BMC, BMD, and VO2 max. The training and position of midfielders require higher physical demands.

Football is a very demanding sport which requires players to exert maximum effort, producing fatigue and eventually injuries. Thermography can be used to detect fatigue and prevent its consequences through thermal asymmetries in the bilateral body areas; however, its adequacy for elite footballers has not been widely studied. Therefore, the objective of the present investigation was to determine the suitability of thermography to detect fatigue in male football players. For this reason, twenty participants were gathered into a pair of subgroups (low [p > 0.05) were found in any of the RSA test variables between low and high thermal asymmetry groups for thighs and calves. On the other hand, the low thermal asymmetry hamstring group reported a smaller percentage difference in sprints for the first sprint (%Diff) and a larger percentage difference in sprints two and three with respect to the best sprint (%Best). For CMJs, the low thermal asymmetry hamstring group reported significantly higher values post-RSA test, indicating better performance. Accordingly, thermography can provide information about performance in CMJ and RSA tests through hamstring asymmetries over 0.2 °C. Meanwhile, larger asymmetries than 0.2 °C in calves and thighs do not seem to be related to performance in these tests; therefore, coaches should consider if it is optimal to align players with high hamstring asymmetries.

In futsal there are two referees on the playing court and their capacity to respond to physical and physiological demands imposed during the game is essential for the success. The futsal characteristics such as size pitch, referees position and rules of games or type of league could impose specific physical efforts probably. The aim of this study were to analyze the physical demands of eight elite referees (age 40 ± 3.43 years; height 1.80 ± 0.03 m; weight 72.84 ± 4.01 kg) from seven matches of Spanish Futsal Cup 2020. The physical activity of each referee during the match was monitored with a Local Positioning System, which was installed on futsal pitch where the matches were played. The data differences were evaluated as Paired-Samples T-Test procedure. The results revealed a similar total distance between halves (2888.39 vs. 2831.51 m). The zone 3 distance (15.1–18 km⋅h–1) showed a significative decrease (p < 0.05) during the match in comparison to the first and second halves (−24.48 m; CI95%: −9.54 to −39.42; ES: 0.56). The number of high-intensity acceleration (−10.29; CI95%; 3.71–16.86; ES: 0.92) and deceleration (−24.86; CI95%; 11.59–38.12; ES: 0.99) decreased in the second half of the match (p < 0.05). Therefore, the use of the tracking device to monitoring physical performance provides knowledge of the specific activity profile from futsal referees. This information to can be useful to design more accurate the training programs.

This study aimed to describe professional soccer players' training responses during a competitive season and to investigate the relationship between these responses with wellbeing and recovery indices. Thirteen professional soccer players from the same Spanish Second Division team were monitored during a sixteen-week in-season period. Players' external loads were analyzed using global positioning measurement units (GPS). Additionally, subjective reporting of sleep quality, sleep duration, fatigue, muscle soreness, and stress were assessed with a customized wellness questionnaire at the beginning of each training session. A two-step cluster analysis identified profiles of different training responses generally described as lower-demand sessions, intermediate-demand sessions, running-based sessions, and sprint-based sessions; which were discriminated by different total distance covered and high-intensity actions. Interestingly, no probabilistic interactions were found between these training responses with wellbeing and recovery markers (i.e., Bayes factor < 1 suggesting no evidence, for all the variables). These findings may raise concerns about using self-reporting tools, as they show that players' wellness data is probably not accounted for when coaching staff plan and optimize the training process. However, results should be interpreted with caution, due to representing a single team and coaching staff.

The aims of this study were to analyze the differences of physical demands of non-starter players regarding the playing time during the competition and to evaluate the physical demands of the compensatory training (MD + 1C) for substitute players in elite football. The match statistics and MD + 1C of substitute players from a professional Spanish LaLiga football club were analyzed using a 10-Hz global positioning system (GPS) Apex GPS system device, which has been validated as a reliable and valid method to analyze performance in team sports, during all games of the 2016/2017, 2017/2018 and 2018/2019 seasons. The starting players showed both lower total distances covered and high-intensity actions compared to the substitutes. Regarding the minutes played by the substitutes, greater physical performance was found for the players with fewer minutes (5–15 min). Furthermore, no differences were found between first and second divisions regarding physical performance of substitutes (p > 0.05). This study highlights the importance of individualizing the workload of training sessions for substitutes and starters. Furthermore, the complementary session should be individualized according to the minutes played by the substitutes. These players are potentially under-loaded compared to starters, especially in terms of high-intensity actions, therefore additional session-specific training for each substitute would be useful to reach the optimal training load according to the minutes played during the game.

Technology has become established in elite sport in recent years and is used on a regular basis, especially in team sports [...]

The aim of this study was to examine the key performance indicators of female professional soccer players during the 2011 and 2015 FIFA Women's World Cup, played on different surfaces (natural and artificial turf respectively). A total of 438 women from 24 national teams who participated at Canada 2015 (artificial turf) and 283 players from 16 national teams who played in Germany 2011 (natural grass) were selected for this study. The collected data were provided by OPTA Sports. Twenty-nine key performance indicators were included for analysis. The variables were calculated for the total sample and independently by positions (defense, midfielders and forwards) for matches on natural grass (2011) and artificial turf (2015). A Mann-Whitney U test was used out to identify differences between the sport surfaces. Moreover, a discriminant analysis was performed with the forced entry method to find the variables that better differentiated between the FIFA Women's World Cup 2011 (natural grass) and FIFA Women's World Cup 2015 (artificial turf). Key performance aspects were very similar between the two tournaments, but on natural grass, we observed a significantly higher number of total passes, successful dribbles, total tackles, successful tackles and interceptions. However, on artificial turf there were significantly higher percentages of success in total passes, and a higher number of fouls. This is an important factor for the choice of an elite competition surface because technical actions are crucial to the quality of the game and can influence the future behavior of spectators and fans.

The aim of this study was to evaluate the validity and reliability of a commercially available local position measurement (LPM) tracking system when assessing distance and running time at different speeds. Fifteen male healthy athletes performed 15 m displacements at walking, running and sprinting speed. Data recorded by the LPM system were compared to those from the reference equipment, consisting of measuring tape and electronic timing gates placed at 0, 5, 10, and 15 m. Mean error, mean absolute error (MAE), standard deviation (SD) of the measurement error, maximum measurement error and root mean square error (RMSE) were calculated to determine the validity for distance and the running time variables. Product-moment correlation and intraclass correlation coefficient (ICC) were also used for the running time. Finally, the reliability of the distance was carried out comparing data from the three repetitions with the standard tape measure using a linear mixed model and the typical error as mean coefficient of variation (CV) (%). MAE shows errors under 0.18 m for the distance variable at all speeds and under 0.08 s for the running time variable at all speeds, except from 15 m at walking. Product-moment correlations were high to nearly perfect for running time (range: 0.60–0.99), ICC varied between high (0.75–0.90) and extremely high (>0.99) for most measures, and coefficients of variation remained almost invariable as speed increased (walking: 2.16; running: 2.52; sprinting: 2.20). The tested LPM system represents a valid and reliable method for monitoring distance during different constant speeds over a straight line, as long as there is no signal loss. However, the running time errors could be too large for performance tests that require acute precision.

The aim of this study was to characterise all the goal scoring patterns during open play (elaborate attacks versus counterattacks) related to zone pitch division and the number of players involved in the 2018 FIFA World Cup in Russia. An Iterative Dichotomiser 3 (ID3) decision tree algorithm was used to classify all the goal scoring patterns (94 goals in 64 matches). The results did not show statistical differences between the type of scoring goal during the 2018 FIFA World Cup (p > 0.05; ES = Moderate). According to the result of the patterns of how the goals were achieved, an ID3 algorithm decision tree with seven classification decision nodes was calculated. Consequently, this study may aid national team coaches for the next World Cup to establish notational analyses and spatial-temporal relations to understand how scoring patterns during open play are related to zone pitch division and the number of players involved.

The aim of this study was to analyse the physical demands of U10 players in a 7-a-side-soccer tournament based on the playing positions in 6 consecutive matches by global positioning systems (GPS). Variables of total distance, relative distance in different speed zones, maximum speed, time interval between accelerations, maximum speed acceleration, maximum acceleration, acceleration distance and the number of high-intensity accelerations were analysed. Differences between playing positions were found in the total distance covered by the midfielders. They covered higher total distances than the defenders (+1167 m; 95% CI: 411 to 1922 m; effect size (ES) = 1.41; p < 0.05) and forwards (+1388 m; CI 95%: 712 a 2063 m; TE = 0.85; p < 0.05). The total covered distance increased in the final rounds with respect to the group stage (p < 0.05; ES: 0.44 to 1.62), and high-intensity actions, such as the number of accelerations, were greater in the final rounds compared to the group stage (p < 0.05; ES: 0.44 to 1.62). The physical performance of young football players in a tournament with consecutive matches on a 40 × 62 m football field on the same day is influenced by the playing position and dependent on the level difference between opponents.

The aim of this study was to analyze the influence of the match half and the playing position on physical requirements in the Spanish Professional Futsal League players during official games. The external load from distance, speed, acceleration and deceleration variables were obtained from fourteen elite futsal players during 10 official matches of the 2019–2020 season using a Local Positioning System with ultra-wideband technology installed on the futsal pitch. The results revealed similar results from physical requirements between first and second half (p > 0.05). Wingers demonstrated greater high-speed running distance (+4.04 m·min−1; CI95%: 0.35 to 7.72; ES: 0.87) than pivots (p > 0.05). There were a high number of accelerations (7.42–9.41 n·min−1) and decelerations (7.37–9.12 n·min−1) per minute in all player positions. The principal finding of the current manuscript did not evidence differences in the physical performance of players between the first and second half. The physical requirements varied among pivots and wingers regarding high-intensity actions. These outcomes add new contributions to the understanding of futsal physical demands.

The mechanical properties of the surfaces used for exercising can affect sports performance and injury risk. However, the mechanical properties of treadmill surfaces remain largely unknown. The aim of this study was, therefore, to assess the shock absorption (SA), vertical deformation (VD) and energy restitution (ER) of different treadmill models and to compare them with those of other sport surfaces. A total of 77 treadmills, 30 artificial turf pitches and 30 athletics tracks were assessed using an advanced artificial athlete device. Differences in the mechanical properties between the surfaces and treadmill models were evaluated using a repeated-measures ANOVA. The treadmills were found to exhibit the highest SA of all the surfaces (64.2 ± 2; p < 0.01; effect size (ES) = 0.96), while their VD (7.6 ± 1.3; p < 0.01; ES = 0.87) and ER (45 ± 11; p < 0.01; ES = 0.51) were between the VDs of the artificial turf and track. The SA (p < 0.01; ES = 0.69), VD (p < 0.01; ES = 0.90) and ER (p < 0.01; ES = 0.89) were also shown to differ between treadmill models. The differences between the treadmills commonly used in fitness centers were much lower than differences between the treadmills and track surfaces, but they were sometimes larger than the differences with artificial turf. The treadmills used in clinical practice and research were shown to exhibit widely varying mechanical properties. The results of this study demonstrate that the mechanical properties (SA, VD and ER) of treadmill surfaces differ significantly from those of overground sport surfaces such as artificial turf and athletics track surfaces but also asphalt or concrete. These different mechanical properties of treadmills may affect treadmill running performance, injury risk and the generalizability of research performed on treadmills to overground locomotion.

The aim of this study was to analyse different success models and split time on cut-off point values on physical demands to keep category in semi-professional football players. An ad hoc observational controlled study was carried out with a total of ten (840 match data) outfield main players (25.2 ± 6.3 years, 1.79 ± 0.75 m, 74.9 ± 5.8 kg and 16.5 ± 6 years of football experience) and monitored using 15 Hz GPS devices. During 14 official matches from the Spanish division B in the 2016/2017 season, match data were coded considering the situational variable (score) and classified by match results (winning, losing or drawing). The results show significant differences between high-intensity attributes criteria that considered split time in velocity zones of 0–15 min (p = 0.043, ηp2 = 0.065, medium), 30–45 min (p = 0.010, ηp2 = 0.094, medium) and 60–75 min (p = 0.015, ηp2 = 0.086, medium), as well as sprint 60–75 min (p = 0.042, ηp2 = 0.066, medium) and 75–90 min (p = 0.002, ηp2 = 0.129, medium). Decision tree induction was applied to reduce the disparity range of data according to six 15-min intervals and to determine the cut-off point values for every parameter combination. It was possible to establish multivariate models for the main high-intensity actions criteria, allowing the establishment of all rules with their attributes and enabling the detection and visualisation of relationships and the pattern sets of variables for determining success.

The aim of this study was to define a reliable and sensitive test method for assessing Shock Absorption (SA), Vertical Deformation (VD), and Energy Restitution (ER) in treadmill surfaces. A total of 42 treadmills belonging to four different models were included in the study: (a) Technogym Jog700 Excite (n = 10), (b) Technogym Artis Run (n = 12), (c) LifeFitness Integrity Series 97T (n = 11), and (d) LifeFitness Integrity Series DX (n = 9). An advanced artificial athlete (AAA) device was used to assess SA, VD, and ER at three different locations along the longitudinal axis of each treadmill and in the support area of the athletes’ feet. For each location, our results show that the error assumed when performing one impact with the AAA instead of three (SA ≤ |0.1|%, VD ≤ |0.0| mm, and ER ≤ |0.2|%) is lower than the smallest changes that can be detected by the measuring device (SA = 0.4%, VD = 0.2 mm, and ER = 0.9%). Also, our results show the ability of the test method to detect meaningful differences between locations once the one-impact criterium is adopted, since absolute minimum differences between zones (SA: |0.6|%, VD: |0.3| mm, and ER: |1.2|%) were above the uncertainty of the measuring device. Therefore, performing a single impact with the AAA in each of the three locations described in this study can be considered a representative and reliable method for assessing SA, VD, and ER in treadmill surfaces.

Assessing and keeping control of the mechanical properties of sport surfaces is a relevant task in sports since it enables athletes to train and compete safely and under equal conditions. Currently, different tests are used for assessing athlete- and ball-surface interactions in artificial turf pitches. In order to make these evaluations more agile and accessible for every facility, it is important to develop new apparatus that enable to perform the tests in an easier and quicker way. The existing equipment for determining the vertical ball behavior requires a complex and non-easily transportable device in which the ball must be fixed to the upper part of the frame in a very precise position by means of a magnet. The rebound height is determined by capturing the acoustic signal produced when the ball bounces on the turf. When extended tests are conducted, the time required to evaluate a single field is too high due to the non-valid trials. This work proposes a novel methodology which allows to notoriously decrease the time of testing fields maintaining the repeatability and accuracy of the test method together with a compact device for improving its mobility and transport. Simulations and experiments demonstrates the repeatability and accuracy of the results obtained by the proposed device, which decreases the non-valid trials and notoriously reduces the time for field evaluation.

The aim of the present study was to assess the accuracy of a multi-camera tracking system (Mediacoach®) to track elite football players’ movements in real time. A total of 207 observations of 38 official matches from Liga 1, 2, 3™ (2nd Spanish Division, season 2017/18) were included in the study (88 defenders, 84 midfielders, and 35 attackers of the same team). Total distance (TD, m) distance in zone 4 (DZ4) at a speed of 14–21 km/h, distance in zone 5 (DZ5) at a speed of 21–24 km/h (DZ5), distance in zone 6 (DZ6) at a speed of ≥24 km/h, maximum speed (km/h), and number of sprints (actions above 24 km/h) were registered with the Apex® GPS system (STATSports™, Newry, N. Ireland) and Mediacoach® semi-automatic tracking system (LaLiga™, Madrid, Spain). The level of agreement between variables estimated by the two systems was analyzed. Bias was also calculated by deducting the GPS estimated value from the video estimated value, and then dividing the difference score by the GPS estimated value. All variables showed high ICC values (>0.75) and very large correlations (r > 0.70). However the video-based performance analysis system overestimated the results obtained in the different speed zones (DZ5: +16.59 ± 62.29 m; LOA95%: −105.49 to 138.68; DZ6: +93.26 ± 67.76 m; LOA95%: −39.55 to 226.07), the number of sprints (+2.27 ± 2.94; LOA95%: −3.49 to 8.02), and the maximum speed (+0.32 ± 1.25 km/h; LOA95%: −2.13 to 2.77). The maximum bias was found in DZ6 (47%). This demonstrates that Mediacoach® is as accurate as a GPS system to obtain objective data in real time, adapted to physical and movement demands of elite football, especially for total distance and distances traveled at medium speeds.

La legislación española ha incluido un nuevo indicador, llamado coste efectivo, para analizar el desarrollo de los servicios municipales (incluidos los deportivos) de forma homogénea entre tipos de gestión, lo que podría sustituir al clásico indicador de gasto por habitante. Así, el objetivo de este artículo es analizar a las implicaciones del coste efectivo como medida de dimensionamiento del deporte a nivel municipal, tomando como referencia el tipo de gestión. Todos los municipios españoles de más de más de 20,000 habitantes formaron parte de este estudio, utilizando los datos procedentes de 2014 y 2015 (297 casos en 2014 y 273 en 2015). Se calcularon dos variables dependientes, gasto por habitante y coste por habitante en deporte, y se estimó un modelo de regresión por cada variable dependiente y año, utilizando el tipo de gestión como variable independiente (gestión directa centralizada, directa descentralizada o indirecta), así como diversos factores del entorno. Los modelos de gasto por habitante muestran más gasto (p0,05). Los coeficientes de las variables de control se mantienen estables en todos los modelos. Por tanto, el uso del coste efectivo por habitante sugiere que el nivel de servicios es similar independientemente el tipo de gestión.

The aim of this study was to evaluate the neuromuscular response to an agility and repeated sprint ability (RSA) test according to the level of competition in futsal players. A total of 33 players from two elite teams and one amateur team participated in the study. The participants completed an agility t-test, a 30 m-speed test, and a RSA test. A countermovement jump (CMJ) test and a tensiomyography test of the rectus femoris (RF) and biceps femoris (BF) of both legs were carried out before and after the tests. RSA test revealed better sprint times in elite players compared to amateurs in the seven bouts, as well as in the 30 m sprint and in the agility test (p < 0.05). Before the tests, elite players showed higher sustain time (Ts) in RF (+31.03 ms; ES: 0.76) and BF (+28.73 ms; ES: 0.73), higher half-relaxation time (Tr) in BF (+20.79 ms; ES: 0.94), and lower delay time (Td) in BF (−2 ms; ES: 1.19) compared to amateur players. However, post-test values did not present any significant differences (p > 0.05). In conclusion, elite players showed greater performance in the RSA test, in the 30 m tests and in the agility test compared to amateur players. The contractile properties were not a key factor in the RSA performance of the futsal players.

The aim of this study was to analyse the effects of the type of extracurricular sport on the body composition, respiratory parameters, and physical condition in prepubertal and pubertal girls. Four hundred and eighty-five female athletes (aged 8–14) from different sports participated in this study. They were gathered into four groups according to the sport typology and maturity level: ‘prepubertal girls who practise collective sports’ (PRE-CS), ‘prepubertal girls who practise individual sports’ (PRE-IS), ‘pubertal girls who practise collective sports’ (PUB-CS), and ‘pubertal girls who practise individual sports’ (PUB-IS). The cardiorespiratory fitness (the 20 m shuttle run test, 20 mSRT), anthropometry, respiratory capacity (forced spirometry), handgrip, CMJ test, and stabilometry were collected. Prepubertal girls showed a lower muscle mass (kg) and fat mass (kg) than pubertal girls regardless of the extracurricular sports typology. PRE-CS and PRE-IS also showed a lower respiratory fitness and physical fitness than pubertal girls (p < 0.05). Pubertal girls did not show significant differences (p > 0.05) in any of the body composition, respiratory fitness, and physical fitness variables when comparing between collective sports and individual sports. The results show that extracurricular participation in these types sports by prepubertal girls can influence their body composition, respiratory fitness, and physical condition.

Abstract. Purpose: One of the main problems detected in the sport centre field is abandonment of physical activity by members. The aim of this estudy is to evaluate the reproducibility of predictive models of abandonment in sports centres, based on information collected through access control and the Customer Relationship Management system. Method: Monthly data corresponding to the actual behaviour of of two sport centres in Spain were recorded over the course of one year (12,545 members). Based on these variables, two predictive models were designed using the absence or permanence in the centre as an independent variable. Subsequently, the regression formula obtained was applied on all members of the same sports centres a year later (12,986 members), checking the effectiveness and reproducibility of the model. Results:. Logistic regression models based on customer historical behaviour were useful to predict abandonment. The effectiveness of the models was around 70% a year after. Conclusions: The segmentation of users based on the likelihood of drop out and the identification of behaviour variables that predict such drop out and the confirmation of the effectiveness of the predictive model, can help to optimize the design of loyalty strategies to prevent the abandonment in sport centres. Resumen. Objetivo: El abandono de la práctica deportiva por parte de clientes en centros deportivos es uno de los principals problemas en el sector. El objetivo de este estudio es evaluar la reproducibilidad de modelos predictivo de abandono en centros deportivos, basados en información recogida a través del control de accesos y el sistema Customer Relationship Management. Método: Se recopiló comportamientos mensuales de los clientes de dos centros deportivos en España durante un año (12,545 members). En base a dichas variables se diseñaron dos modelos predictivos utilizando la baja o permanencia en el centro como variable independiente. Posteriormente, se aplicó la formula de regression obtenida sobre todos los miembros de los mismos centros deportivos un año después (12,986 members), comprobando la efectividad y reproducibilidad del modelo. Resultados: Las estimaciones de regression logística fueron útiles para predecir el abandon en los centros deportivos. Además, reproduciendo el mismo modelos en una muestra diferente se consiguió aproximadamente un 70% de efectividad. Conclusiones: La segmentación de usuarios en base a la probabilidad de baja y la identificación de variables predictivas de dicha baja pueden optimizar el diseño de estrategias de prevención de abanadono en centros deportivos.

El objetivo del presente estudio fue analizar la estructura temporal y las acciones características del pádel de élite. Se analizaron 9 torneos del Padel Pro Tour® 2012 con un total de 28 partidos y 59 sets (32 categoría masculina vs. 27 femenina). Los partidos fueron analizados mediante el software LongMatch V.0.20.1®, comparando ítems sobre aspectos temporales y acciones de juego entre hombres y mujeres. Los resultados ponen de manifiesto diferencias significativas en la mayoría de las variables temporales analizadas. Además, se encontró que el índice de esfuerzo fue significativamente superior en mujeres que en hombres. Por otro lado, las acciones de juego como el número de globos/punto o el número de golpes/punto también fueron significativamente superiores en mujeres con respecto a los hombres. Se podría afirmar que el pádel de élite es un deporte caracterizado por puntos de corta duración alternados con breves periodos de pausa, lo que implica una alta densidad de trabajo, donde el género influye significativamente en las variables temporales y acciones de juego.

The purpose of this study was to adapt the questionnaire of Preuss, Seguin and O’Reilly (2007) to Portuguese reality to analyse the phenomenon of consumption patterns of non-residents spectators at sporting events. For this, an exploratory study was conducted to check its psychometric properties when applied to Portuguese reality. For the sample, 58 non-resident spectators were randomly selected in the match between Futebol Clube Paços de Ferreira and Sporting Clube de Portugal of 19th round of Liga NOS in the city of Paços de Ferreira. Data analysis was based on descriptive statistics and Cronbach’s alpha reliability test. The results suggest acceptable values for internal consistency and reliability. As main conclusions, the adapted version can be used to analyse the profile and consumption patterns of non-residents spectators, which will help to define marketing strategies more effective and efficient for clubs and host cities, thus contributing to improving offer and more quality in the services provided for spectators of such events.

This case study explored how spatiotemporal data can develop key metrics to evaluate and understand elite soccer referees' performance during one elite soccer match. The dynamic position of players from both teams, the ball and three elite referees allowed to capture the following performance metrics: (i) assistant referees: alignment with the second last defender; (ii) referee: referee diagonal movement—a position density was computed and a principal component analysis was carried to identify the directions of greatest variability; and (iii) referee: assessing the distance from the referee to the ball. All computations were processed when the ball was in-play and separated by 1st and 2nd halves. The first metric showed an alignment lower than 1 m between the assistant referee and the second last defender. The second metric showed that in the 1st half, the referee position ellipsis area was 548 m2, which increased during the 2nd half (671 m2). The third metric showed an increase in the distance from the referee to the ball and >80% of the distance between 5–30 m during the 2nd half. The findings may be used as a starting point to elaborate normative behavior models from the referee's movement performance in soccer. [ABSTRACT FROM AUTHOR]

Previous studies have analysed the influence of contextual variables on performance and physical demands in soccer. However, the points needed to remain in the category have been an element that has not been analysed previously. The aim of the present study was to investigate the influence of match location, match period, strength of the opponent and the points required to keep category on physical performance in professional soccer players. Fourteen Spanish second B Division League matches played by a professional football team were analysed during the 2016/17 season using GPS devices. The 10 main players of each match used the GPS throughout the match. The variables of Total Distance (m), High Intensity Distance (m), High intensity Accelerations (n), Sprint Time (s) and Sprint Distance (m) were analysed. The most notable differences are found in Total Distance covered. Away games accumulated significantly more distance than those played at home, but only in the second half (+230.65 m, IC95%: 21.94 to 438.19, ES: 0.46, p = 0.031). There are no differences depending on the strength of the opponent. However, players covered greater distances during the first half in those matches that were played furthest from salvation (+235.86 m, 95% CI: 49.03 to 422.70, ES: 0.51, p = 0.014). Total Distance is the main parameter affected by situational variables. In addition, the pressure of being further away from saving the category increases the distance covered by players in a game.

The aim of this study is to learn more about the physical activity habits of participants in a popular sporting event such as European Sports Day, which is held simultaneously in five European countries (Spain, Italy, Cyprus, Ireland, and Hungary), and to measure the influence of socio-demographic variables on these habits. This is a cross-sectional study conducted with a sample of 856 participants, stratified by gender, age, and nationality. We statistically analyzed five variables related to physical activity habits: frequency of physical activity practice, places of practice, motives of practice, perceived fitness level, and popular event attendance. Of the participants, 76.8% said they perform physical activity weekly. Fitness/health improvement (34.63%) and entertainment/leisure (26.52%) are the main reasons for the practice of physical activity. Age and nationality are differentiating factors on physical activity habits.

En los últimos años, la demanda de práctica deportiva en campos de fútbol de césped artificial y natural ha crecido exponencialmente. Así surge la necesidad de conocer cuál es el grado de satisfacción tanto de entrenadores como de deportistas sobre estos dos tipos de pavimentos deportivos. Esta investigación se basa en un estudio cuantitativo, a través de dos cuestionarios de satisfacción sobre estos pavimentos. La muestra del estudio la conforman 75 entrenadores y 368 deportistas, que realizan su actividad deportiva en campos de césped natural y artificial, de la Región de Murcia. Los resultados obtenidos muestran una preferencia de los agentes analizados por el césped artificial en gran parte de las variables, aunque la valoración general obtenida no presenta diferencias significativas. Aunque a medida que aumenta la categoría en la que participan los sujetos también aumenta su preferencia por la superficie natural.

The aim of this investigation is to evaluate the quality of the sports facilities and equipment of High Schools, according with current regulations. This is a quantitative research methodology, with descriptive character, using several check lists designed explicitly for this investigation. The sample consists of 21 High Schools. The results obtained, show us that 90.48% of High Schools have «open spaces» for the practice of physical activity, but only 61.90% of them have open spaces according with the regulations N.I.D.E. (Legislation about Sport Facilities and Recreation). In terms of «covered spaces», there is a 85,71% of High Schools that include these spaces to carry out the Physical Education classes, although the existing covered area does not comply the regulations currently in force in the 76.19% of the cases. This study shows that high school sports facilities, have serious shortcomings, especially m2 available in sporting and complementary, so it would be very positive that the current regulations (N.I.D.E.) are granted a prescriptive character, so that would be mandatory for High Schools, and able to sue a better endowment to the corresponding educational Administration.

The aim of this research was to evaluate the influence of the mechanical properties of artificial turf systems on soccer players' performance. A battery of perceptive physiological and physical tests were developed on four different structural systems of artificial turf (System 1: Compacted gravel sub-base without elastic layer; System 2: Compacted gravel sub-base with elastic layer; System 3: Asphalt sub-base without elastic layer; System 4: Asphalt sub-base with elastic layer). The sample was composed of 18 soccer players (22.44±1.72 years) who typically train and compete on artificial turf. The artificial turf system with less rotational traction (S3) showed higher total time in the Repeated Sprint Ability test in comparison to the systems with intermediate values (49.46±1.75 s vs 47.55±1.82 s (S1) and 47.85±1.59 s (S2); p0.05). The physiological load was similar in all four artificial turf systems. However, players felt more comfortable on the harder and more rigid system (S4; visual analogue scale = 70.83±14.28) than on the softer artificial turf system (S2; visual analogue scale = 54.24±19.63). The lineal regression analysis revealed a significant influence of the mechanical properties of the surface of 16.5%, 15.8% and 7.1% on the mean time of the sprint, the best sprint time and the maximum mean speed in the RSA test respectively. Results suggest a mechanical heterogeneity between the systems of artificial turf which generate differences in the physical performance and in the soccer players' perceptions.

En las últimas décadas, el césped artificial está sufriendo una constante evolución, no solo en la cantidad, sino también en la calidad de sus componentes estructurales. Este crecimiento ha originado la necesidad de conocer el estado de los pavimentos artificiales en relación a unos estándares de calidad previamente determinados, surgiendo diferentes normativas en base a la finalidad y categoría de la superficie. Actualmente, existen tres sistemas de homologación diferentes para este tipo de superficies. Por un lado, la norma UNE-EN 15330-1:2007, específica para superficies deportivas de hierba artificial de uso exterior, más orientada para deportes comunitarios, educativos y de ocio, y por otro, las que guardan una mayor relación con el alto rendimiento deportivo, como la certificación FIFA (1 y 2 estrellas), de carácter internacional, y la Marca de Calidad de la RFEF (nivel 1 y 2), de ámbito nacional. La implantación de estas acreditaciones garantiza la calidad del pavimento, mejorando sus prestaciones y situándolo a la altura de la hierba natural.

BACKGROUND: Swimming in indoor pools treated with combined chemical treatments (e.g. ozone) may reduce direct exposure to disinfection byproducts and thus have less negative effects on respiratory function compared to chlorinated pools. The aim of this study is to analyze the effects of a short-term training intervention on respiratory function and lung epithelial damage in adults exercising in indoor swimming pool waters treated with different disinfection methods (chlorine vs. ozone with bromine). METHODS: Lung permeability biomakers [surfactant protein D (SP-D) and Clara cell secretory protein (CC16) in plasma] and forced expiratory volumes and flow (FEV1, FVC and FEF25-75) were measured in 39 healthy adults. Thirteen participants swam during 20 sessions in a chlorinated pool (CP), 13 performed and equivolumic intervention in an ozone pool (OP) and 13 were included in a control group (CG) without exposition. RESULTS: Median plasma CC16 levels increased in CP swimmers (4.27 ± 3.29 and 6.62 ± 5.51 µg/L, p=0.01, pre and post intervention respectively) while no significant changes in OP and CG participants were found. No significant changes in median plasma SP-D levels were found in any of the groups after the training period. FVC increased in OP (4.26 ± 0.86 and 4.43 ± 0.92 L, p

Como objetivo de esta investigación nos planteamos evaluar la calidad de las instalaciones deportivas y el equipamiento de los Institutos de Educación Secundaria, comprobando si cumplen la normativa vigente. Se trata de una investigación de metodología cuantitativa, con carácter descriptivo, a través del uso de varias listas de control, diseñadas expresamente para esta investigación. La muestra está formada por 21 centros educativos de Ciudad Real. Los resultados obtenidos nos muestran que el 90,48% de los centros escolares cuentan con espacios abiertos para la práctica de la actividad física, pero sólo el 61,90% cuentan con espacios abiertos que cumplen la Normativa sobre Instalaciones Deportivas y de Esparcimiento (N.I.D.E.). En referencia a los espacios cubiertos, el porcentaje de centros educativos que cuentan con estos espacios para realizar las clases de Educación Física es de un 85,71%, aunque el espacio cubierto existente no cumple la normativa vigente en el 76,19% de los casos. Este estudio muestra que las instalaciones deportivas escolares, presentan grandes carencias, sobre todo de m2 disponibles, en espacios deportivos y complementarios, por lo que sería muy positivo que a la normativa N.I.D.E. se le otorgase un carácter prescriptivo para los centros educativos, pudiéndose así, demandar una mejor dotación a la Administración educativa correspondiente. Palabra clave: Instalaciones deportivas escolares, equipamiento deportivo, espacios descubiertos y espacios cubiertos. Abstract: The aim of this investigation is to evaluate the quality of the sports facilities and equipment of High Schools, according with current regulations. This is a quantitative research methodology, with descriptive character, using several check lists designed explicitly for this investigation. The sample consists of 21 High Schools. The results obtained, show us that 90.48% of High Schools have «open spaces» for the practice of physical activity, but only 61.90% of them have open spaces according with the regulations N.I.D.E. (Legislation about Sport Facilities and Recreation). In terms of «covered spaces», there is a 85,71% of High Schools that include these spaces to carry out the Physical Education classes, although the existing covered area does not comply the regulations currently in force in the 76.19% of the cases. This study shows that high school sports facilities, have serious shortcomings, especially m2 available in sporting and complementary, so it would be very positive that the current regulations (N.I.D.E.) are granted a prescriptive character, so that would be mandatory for High Schools, and able to sue a better endowment to the corresponding educational Administration. Key words: Sports facilities, sports equipment, open spaces and covered spaces.