El objetivo de este estudio fue elaborar una herramienta especifica para evaluar el nivel de impl... more El objetivo de este estudio fue elaborar una herramienta especifica para evaluar el nivel de implantacion de buenas practicas en la organizacion de programas deportivos orientados al fomento y mejora de la salud. Para ello, se diseno un instrumento ad hoc partiendo de una revision bibliografica previa al que se llamo “Piloto de Trabajo”. Este documento fue sometido a la revision de un grupo de discusion hasta obtener un nivel de consenso adecuado. Seguidamente, se realizo una prueba piloto por dos investigadores de manera independiente, seleccionando 5 programas de buenas practicas deportivas saludables en Espana. La version final de la herramienta quedo compuesta por un total de 21 items, divididos en dos bloques: comun (4 items) y especifico (17 items). El instrumento de medida, denominado EVESBEPRAH, mostro buenos indices de validez (V de Aiken ≥ .96) y fiabilidad (К = .8122). Esta herramienta pretende orientar a los planificadores de programas deportivos hacia las buenas practic...
This study examined physical and technical demands and the influence of the team's level on elite... more This study examined physical and technical demands and the influence of the team's level on elite goalkeepers' performance during six consecutive seasons in Spanish Professional Soccer League. The goalkeepers' performance data were obtained by analyzing a total of 3,874 matches using a multiple-camera computerized tracking system. The physical and technical match variables registered were: distance traveled; distance Sprinted and the number of sprints; total number of passes; successful passes; pass percentage; recovered balls; lost balls; ratio lost balls: recovered balls, and number of saves. The results showed that the number of saves made has shown a significant reduction (p < 0.001). When comparing between the teams' level, the goalkeepers of the worst classified teams showed a greater distance traveled by sprint (+3.72 m, IC95%: 1.00-6.44, ES: 0.41, p = 0.008). In conclusion, the results the influence of the team's level on the technical and physical parameters of the goalkeepers during the last six seasons.
The aim of this study was to evaluate the effect of a repeated sprint ability (RSA) test on the c... more The aim of this study was to evaluate the effect of a repeated sprint ability (RSA) test on the contractile properties of the muscles in elite futsal players. A total of 20 elite players completed the RSA test (7 × 30 m), and the contractile response from the rectus femoris (RF) and biceps femoris (BF) of both legs were analysed pre and post through tensiomyography. There was a significant increment in 30-m times from the third sprint onwards (p < 0.05). The percent decrement in sprint ability (RSADEC) with respect to the first sprint was significantly higher in the last sprint. The players did not show evidence of lateral asymmetry in any of the muscle groups analysed after the RSA test (p > 0.05). Following the RSA test there was a significant reduction in the delay time (Td) in RF, a significant decrement in half-relaxation time (Tr) in the RF, and a significant reduction in sustain time (Ts) in the RF and BF of both legs. The maximum radial displacement of the muscle belly...
Lean mass is a strong determinant of bone mass, however, there is controversial surrounding the r... more Lean mass is a strong determinant of bone mass, however, there is controversial surrounding the role of fat mass. The aim of this study was to examine the association between lean mass and fat mass with bone mass in middle-aged sedentary women, including relevant covariates. A cross-sectional study was performed on a total of 55 healthy and sedentary women. Dual energy x-ray absorptiometry was used to measure bone mineral content and areal bone mineral density at the whole body, lumbar spine and hip. The relationships between lean and fat mass with bone outcomes were analysed using three regression models: model 0 using unadjusted data, model 1 was adjusted by age and stature and model 2 added lean mass or fat mass (depending on the predictor). Lean mass was positively associated with most bone mineral content and areal bone mineral density outcomes in models 0 and 1, and the majority of these associations remained significant in model 2 (after adjusted by fat mass). Fat mass was positively associated with some of the bone mineral content and areal bone mineral density outcomes in models 0 and 1, and interestingly all associations disappeared in model 2 (after adjusted by lean mass). The main finding of this study was that lean mass was positively related to bone outcomes, independent of age, stature and fat mass in middle-aged sedentary women. In addition, the association between fat mass and bone outcomes seems to be explained by lean mass.
Journal of strength and conditioning research, Jan 22, 2017
The aim of this research was to evaluate the influence of game surface and pitch size on the move... more The aim of this research was to evaluate the influence of game surface and pitch size on the movement profile in female soccer players during Small-Sided-Games (SSGs) of 4 v 4. 16 women played three different 4-a-side (400 m, 600 m and 800 m) on three surfaces (ground [GR], artificial turf [AT] and natural grass [NG]). Time-motion variables were assessed through GPS devices (Spi Pro X, GPSports, Australia). GR had the worst outputs on most variables. NG achieved higher results than AT in terms of total distance [SSG 400 (+37.000 m; p=0.006); SSG 600 (+59.989 m; p<0.001); SSG 800 (+42.284 m; p=0.001)]. On the other hand, the smaller SSG (400) had the lowest values on most variables. However, while the middle SSG (600) presented higher output than the bigger one (800) for Body Load [NG (+7.745 a.u.; p<0.001); AT (+8.207 a.u.; p<0.001); GR (+5.879 a.u.; p<0.001)], it had lower results for High Intensity Distance [NG (-13.15 m; p=0.025); AT (-13.59 m; p=0.026)]. Despite wome...
This study investigated the associations between fitness indices and bone outcomes in young males... more This study investigated the associations between fitness indices and bone outcomes in young males. Data were collected between autumn and winter 2014-2015 on 121 males with a mean age of 13.1 ± 0.1 years: 41 swimmers, 37 footballers, 29 cyclists and 14 nonathletes. Participants were recruited from athletic clubs and schools across South West England. Lean mass, areal bone mineral density and hip structural estimates were measured using dual-energy X-ray absorptiometry. The relationships between bone outcomes and the vertical jump, standing long jump and the 20-m shuttle run test were analysed using three regression models: model 1 was adjusted by age and stature, model 2 added vigorous physical activity and model 3 then added lean mass. The boys' performance in the vertical jump and standing long jump was positively associated with the majority of bone outcomes in models 1 and 2, but most of these disappeared in model 3. The 20-m shuttle run test was positively associated with m...
Small-sided-games (SSGs) seem to be a useful tool for replicating most types of scenarios found i... more Small-sided-games (SSGs) seem to be a useful tool for replicating most types of scenarios found in sport competitions, but it is not that clear in female soccer. Game surface and pitch size seem to affect the intensity of SSGs, but no one has yet analysed the influence of these two variables together. The objective of this research was to analyse the metabolic power demands of various SSGs on possession play without goalkeepers , played on three different surfaces. Sixteen sub-elite female players performed three different four-aside games (400 m 2 , 600 m 2 , and 800 m 2) on three different surfaces (ground [GR]; natural grass [NG]; and artificial turf [AT]), recording a total of 96 events. Metabolic variables were recorded through a global positioning system (GPS). The GR condition obtained the lowest outputs for all variables in all of the SSGs. Furthermore, NG resulted in higher outcomes than AT for Average Metabolic Power (SSG 400 [+0.65; p = 0.019]; SSG 600 [+0.70; p = 0.04]); and equivalent distance (SSG 400 [+33.0; p = 0.02]; SSG 600 [+36.53; p = 0.04]). Moreover, SSG 400 obtained lower results than SSG 600 and SSG 800 for both AT and NG. In conclusion, playing on GR reduces the metabolic power of SSGs, While NG seems to be the most suitable surface for attaining highest metabolic responses for sub-elite female players. On the other hand, too big a pitch size may not increase the metabolic demands of the game.
The third generation of artificial turf systems (ATS) has matched the mechanical behaviour of nat... more The third generation of artificial turf systems (ATS) has matched the mechanical behaviour of natural grass, but today a high heterogeneity at structural level and mechanical behaviour in the new ATS also exists. The objective was to analyse the effect of the structural components of ATS football pitches and running speed on the capacity of impact attenuation. A total of 12 athletes were evaluated at three speed conditions (3.33 m/s, 4 m/s and maximum speed) on four different ATS, classifying them by their components (length of fibre, type of in-fill and sub-base). Impact attenuation was significantly higher in ATS3, characterised by longer fibre compared to other ATS with less fibre length. The ATS4 with a higher length fibre and built on compacted granular material proportioned significantly lower values in the maximum peaks of tibia acceleration. Finally, as speed increases, the peak tibia impacts were significantly higher. Longer fibre length and the capacity to accommodate a higher quantity of infill facilitate higher impact attenuation. Equally, a compacted granular sub-base is related to lower magnitude of maximum tibia peaks. Finally, the magnitude of the tibia acceleration peaks is dependent of running speed for all ATS analysed, being higher as speed increases.
Journal of strength and conditioning research / National Strength & Conditioning Association, Jan 12, 2016
The aim of this study is to evaluate the physical and physiological load imposed on amateur footb... more The aim of this study is to evaluate the physical and physiological load imposed on amateur football players in a simulated game situation on different artificial turf systems. For that purpose, 20 football players (21.65±3.10 years old) were monitored with Global Positioning Systems and heart rate bands during 45 minute games on four selected artificial turf systems. The results show more covered distance in highintensity ranges on the system with lower levels of damping and higher rates of rotational traction (p<0.05). Likewise, this system of artificial turf demonstrated a high number of sprints (12.65±5.67), as well as more elevated maximum speed peaks during the last part of the game (28.16±2.90 km/h) in contrast to the systems with better damping capacity (p<0.05). On the other hand, the physiological load was similar across the four artificial turf systems (p>0.05). Finally, the regression analysis demonstrated a significant influence of the mechanical properties of ...
The accumulation of bone mass during puberty is related with bone health in adulthood. This accum... more The accumulation of bone mass during puberty is related with bone health in adulthood. This accumulation is influenced by diverse factors such as body mass index (BMI), maximal oxygen uptake (VO 2 max), hours of training and years of sport practice. For this reason, the objective of this study is to analyse the influence of these variables on bone mass in young female athletes. The sample is formed of 120 healthy girls with ages between 9 and 13 (11.32 ± 1.6 years old), divided into two groups depending on their BMI, VO 2 max, hours of training and years of sport practice. The participants completed a series of tests to evaluate level of sexual development, body composition (fat mass, lean mass and bone mass) and physical condition. The results show higher values of total lean mass, total fat mass and percentage of body fat in the groups with higher BMI in prepubertal girls and pubertal girls (p < .05). In relation to VO 2 max, in the prepubertal group, girls with lower VO 2 max had higher values of total fat mass (p < .05) and percentage of body fat (p < .05). In the pubertal group, girls with lower VO 2 max also showed a higher total fat mass (p < .05). The studied variables account for a 85% and 75.4% of the variance of total bone mineral content and bone mineral density (BMD), respectively. In conclusion, the content and BMD are closely related with muscle mass and sports practice in young females. The amount of fat mass showed no association with bone mass and physical condition has an indirect relationship with bone development.
South African Journal for Research in Sport, Physical Education and Recreation
This study identified the most important parameters for the design and safety of artificial turf ... more This study identified the most important parameters for the design and safety of artificial turf football fields according to professional footballers and coaches. Two semi-structured interviews were conducted. The sample consisted of 32 professional players and 25 professional coaches. The players and coaches emphasised that the main problem with artificial turf was the increased risk of injury. The consensus of the interviewees was that it is essential for artificial turf to be installed gradually in elite competitions, starting with youth football. It would allow players to be slowly acclimatised to the surface through their developmental stages. When they reach elite competitions, they would be able to play comfortably either on natural or artificial turf with fewer problems.
The aim of this study is to learn more about the physical activity habits of participants in a po... more 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.
Proceedings of the Institution of Mechanical Engineers, Part P: Journal of Sports Engineering and Technology, 2014
Football fields of artificial turf are in constant evolution. The resulting improvements have giv... more Football fields of artificial turf are in constant evolution. The resulting improvements have given rise to a large diversity of structural components. There are various types of infill and fibre for artificial turf and different designs and materials for the support structure (sub-base and elastic layer). The design of the sub-base and the presence or absence of the elastic layer can influence turf performance and the surface’s useful lifetime. The aim of this study was to assess in situ the effect of the various support structures on the mechanical properties of artificial turf after deterioration caused by wear for a year. The assessed properties were force reduction (%), standard vertical deformation (mm), rotational traction (N·m), vertical ball rebound (%), and ball roll (m), according to the requirements in norm EN 15330-1:2007. The results demonstrate the effect of the structural base on the mechanical and functional performance of football fields of artificial turf, as well...
The aim of the study was to compare the effects of an in-season five weeks of high-intensity trai... more The aim of the study was to compare the effects of an in-season five weeks of high-intensity training (HIT) with a concurrent HIT eccentric overload training (CT) program on male amateur team-sports players’ fitness performance. Twenty-two athletes were randomly assigned to HIT (n=10) or CT (n=12). Both groups completed a HIT program. The CT group also completed two-three sets of six repetitions of eccentric overload training. Before and after training, performance was assessed for change of direction ability (COD), repeated sprint ability for best time (RSAb), mean time (RSAm) and slowest time (RSAs), jumping, and shuttle-run performance. Within-group analyses in both groups showed substantial better scores on COD, RSAb and RSAm and shuttle-run performance. Between-group analyses showed greater improvements in COD, RSAb, RSAm, RSAs, and jumping after additional CT compared to solely HIT. In conclusion, compared to HIT alone, concurrent eccentric overload and HIT training within the...
The aim of this research was to evaluate the influence of the mechanical properties of artificial... more 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 (22.4461.72 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 (49.4661.75 s vs 47.5561.82 s (S1) and 47.8561.59 s (S2); p,0.001). The performance in jumping tests (countermovement jump and squat jump) and ball kicking to goal decreased after the RSA test in all surfaces assessed (p,0.05), since the artificial turf system did not affect performance deterioration (p.0.05). 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 = 70.83614.28) than on the softer artificial turf system (S2; visual analogue scale = 54.24619.63). 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.
El objetivo de este estudio fue elaborar una herramienta especifica para evaluar el nivel de impl... more El objetivo de este estudio fue elaborar una herramienta especifica para evaluar el nivel de implantacion de buenas practicas en la organizacion de programas deportivos orientados al fomento y mejora de la salud. Para ello, se diseno un instrumento ad hoc partiendo de una revision bibliografica previa al que se llamo “Piloto de Trabajo”. Este documento fue sometido a la revision de un grupo de discusion hasta obtener un nivel de consenso adecuado. Seguidamente, se realizo una prueba piloto por dos investigadores de manera independiente, seleccionando 5 programas de buenas practicas deportivas saludables en Espana. La version final de la herramienta quedo compuesta por un total de 21 items, divididos en dos bloques: comun (4 items) y especifico (17 items). El instrumento de medida, denominado EVESBEPRAH, mostro buenos indices de validez (V de Aiken ≥ .96) y fiabilidad (К = .8122). Esta herramienta pretende orientar a los planificadores de programas deportivos hacia las buenas practic...
This study examined physical and technical demands and the influence of the team's level on elite... more This study examined physical and technical demands and the influence of the team's level on elite goalkeepers' performance during six consecutive seasons in Spanish Professional Soccer League. The goalkeepers' performance data were obtained by analyzing a total of 3,874 matches using a multiple-camera computerized tracking system. The physical and technical match variables registered were: distance traveled; distance Sprinted and the number of sprints; total number of passes; successful passes; pass percentage; recovered balls; lost balls; ratio lost balls: recovered balls, and number of saves. The results showed that the number of saves made has shown a significant reduction (p < 0.001). When comparing between the teams' level, the goalkeepers of the worst classified teams showed a greater distance traveled by sprint (+3.72 m, IC95%: 1.00-6.44, ES: 0.41, p = 0.008). In conclusion, the results the influence of the team's level on the technical and physical parameters of the goalkeepers during the last six seasons.
The aim of this study was to evaluate the effect of a repeated sprint ability (RSA) test on the c... more The aim of this study was to evaluate the effect of a repeated sprint ability (RSA) test on the contractile properties of the muscles in elite futsal players. A total of 20 elite players completed the RSA test (7 × 30 m), and the contractile response from the rectus femoris (RF) and biceps femoris (BF) of both legs were analysed pre and post through tensiomyography. There was a significant increment in 30-m times from the third sprint onwards (p < 0.05). The percent decrement in sprint ability (RSADEC) with respect to the first sprint was significantly higher in the last sprint. The players did not show evidence of lateral asymmetry in any of the muscle groups analysed after the RSA test (p > 0.05). Following the RSA test there was a significant reduction in the delay time (Td) in RF, a significant decrement in half-relaxation time (Tr) in the RF, and a significant reduction in sustain time (Ts) in the RF and BF of both legs. The maximum radial displacement of the muscle belly...
Lean mass is a strong determinant of bone mass, however, there is controversial surrounding the r... more Lean mass is a strong determinant of bone mass, however, there is controversial surrounding the role of fat mass. The aim of this study was to examine the association between lean mass and fat mass with bone mass in middle-aged sedentary women, including relevant covariates. A cross-sectional study was performed on a total of 55 healthy and sedentary women. Dual energy x-ray absorptiometry was used to measure bone mineral content and areal bone mineral density at the whole body, lumbar spine and hip. The relationships between lean and fat mass with bone outcomes were analysed using three regression models: model 0 using unadjusted data, model 1 was adjusted by age and stature and model 2 added lean mass or fat mass (depending on the predictor). Lean mass was positively associated with most bone mineral content and areal bone mineral density outcomes in models 0 and 1, and the majority of these associations remained significant in model 2 (after adjusted by fat mass). Fat mass was positively associated with some of the bone mineral content and areal bone mineral density outcomes in models 0 and 1, and interestingly all associations disappeared in model 2 (after adjusted by lean mass). The main finding of this study was that lean mass was positively related to bone outcomes, independent of age, stature and fat mass in middle-aged sedentary women. In addition, the association between fat mass and bone outcomes seems to be explained by lean mass.
Journal of strength and conditioning research, Jan 22, 2017
The aim of this research was to evaluate the influence of game surface and pitch size on the move... more The aim of this research was to evaluate the influence of game surface and pitch size on the movement profile in female soccer players during Small-Sided-Games (SSGs) of 4 v 4. 16 women played three different 4-a-side (400 m, 600 m and 800 m) on three surfaces (ground [GR], artificial turf [AT] and natural grass [NG]). Time-motion variables were assessed through GPS devices (Spi Pro X, GPSports, Australia). GR had the worst outputs on most variables. NG achieved higher results than AT in terms of total distance [SSG 400 (+37.000 m; p=0.006); SSG 600 (+59.989 m; p<0.001); SSG 800 (+42.284 m; p=0.001)]. On the other hand, the smaller SSG (400) had the lowest values on most variables. However, while the middle SSG (600) presented higher output than the bigger one (800) for Body Load [NG (+7.745 a.u.; p<0.001); AT (+8.207 a.u.; p<0.001); GR (+5.879 a.u.; p<0.001)], it had lower results for High Intensity Distance [NG (-13.15 m; p=0.025); AT (-13.59 m; p=0.026)]. Despite wome...
This study investigated the associations between fitness indices and bone outcomes in young males... more This study investigated the associations between fitness indices and bone outcomes in young males. Data were collected between autumn and winter 2014-2015 on 121 males with a mean age of 13.1 ± 0.1 years: 41 swimmers, 37 footballers, 29 cyclists and 14 nonathletes. Participants were recruited from athletic clubs and schools across South West England. Lean mass, areal bone mineral density and hip structural estimates were measured using dual-energy X-ray absorptiometry. The relationships between bone outcomes and the vertical jump, standing long jump and the 20-m shuttle run test were analysed using three regression models: model 1 was adjusted by age and stature, model 2 added vigorous physical activity and model 3 then added lean mass. The boys' performance in the vertical jump and standing long jump was positively associated with the majority of bone outcomes in models 1 and 2, but most of these disappeared in model 3. The 20-m shuttle run test was positively associated with m...
Small-sided-games (SSGs) seem to be a useful tool for replicating most types of scenarios found i... more Small-sided-games (SSGs) seem to be a useful tool for replicating most types of scenarios found in sport competitions, but it is not that clear in female soccer. Game surface and pitch size seem to affect the intensity of SSGs, but no one has yet analysed the influence of these two variables together. The objective of this research was to analyse the metabolic power demands of various SSGs on possession play without goalkeepers , played on three different surfaces. Sixteen sub-elite female players performed three different four-aside games (400 m 2 , 600 m 2 , and 800 m 2) on three different surfaces (ground [GR]; natural grass [NG]; and artificial turf [AT]), recording a total of 96 events. Metabolic variables were recorded through a global positioning system (GPS). The GR condition obtained the lowest outputs for all variables in all of the SSGs. Furthermore, NG resulted in higher outcomes than AT for Average Metabolic Power (SSG 400 [+0.65; p = 0.019]; SSG 600 [+0.70; p = 0.04]); and equivalent distance (SSG 400 [+33.0; p = 0.02]; SSG 600 [+36.53; p = 0.04]). Moreover, SSG 400 obtained lower results than SSG 600 and SSG 800 for both AT and NG. In conclusion, playing on GR reduces the metabolic power of SSGs, While NG seems to be the most suitable surface for attaining highest metabolic responses for sub-elite female players. On the other hand, too big a pitch size may not increase the metabolic demands of the game.
The third generation of artificial turf systems (ATS) has matched the mechanical behaviour of nat... more The third generation of artificial turf systems (ATS) has matched the mechanical behaviour of natural grass, but today a high heterogeneity at structural level and mechanical behaviour in the new ATS also exists. The objective was to analyse the effect of the structural components of ATS football pitches and running speed on the capacity of impact attenuation. A total of 12 athletes were evaluated at three speed conditions (3.33 m/s, 4 m/s and maximum speed) on four different ATS, classifying them by their components (length of fibre, type of in-fill and sub-base). Impact attenuation was significantly higher in ATS3, characterised by longer fibre compared to other ATS with less fibre length. The ATS4 with a higher length fibre and built on compacted granular material proportioned significantly lower values in the maximum peaks of tibia acceleration. Finally, as speed increases, the peak tibia impacts were significantly higher. Longer fibre length and the capacity to accommodate a higher quantity of infill facilitate higher impact attenuation. Equally, a compacted granular sub-base is related to lower magnitude of maximum tibia peaks. Finally, the magnitude of the tibia acceleration peaks is dependent of running speed for all ATS analysed, being higher as speed increases.
Journal of strength and conditioning research / National Strength & Conditioning Association, Jan 12, 2016
The aim of this study is to evaluate the physical and physiological load imposed on amateur footb... more The aim of this study is to evaluate the physical and physiological load imposed on amateur football players in a simulated game situation on different artificial turf systems. For that purpose, 20 football players (21.65±3.10 years old) were monitored with Global Positioning Systems and heart rate bands during 45 minute games on four selected artificial turf systems. The results show more covered distance in highintensity ranges on the system with lower levels of damping and higher rates of rotational traction (p<0.05). Likewise, this system of artificial turf demonstrated a high number of sprints (12.65±5.67), as well as more elevated maximum speed peaks during the last part of the game (28.16±2.90 km/h) in contrast to the systems with better damping capacity (p<0.05). On the other hand, the physiological load was similar across the four artificial turf systems (p>0.05). Finally, the regression analysis demonstrated a significant influence of the mechanical properties of ...
The accumulation of bone mass during puberty is related with bone health in adulthood. This accum... more The accumulation of bone mass during puberty is related with bone health in adulthood. This accumulation is influenced by diverse factors such as body mass index (BMI), maximal oxygen uptake (VO 2 max), hours of training and years of sport practice. For this reason, the objective of this study is to analyse the influence of these variables on bone mass in young female athletes. The sample is formed of 120 healthy girls with ages between 9 and 13 (11.32 ± 1.6 years old), divided into two groups depending on their BMI, VO 2 max, hours of training and years of sport practice. The participants completed a series of tests to evaluate level of sexual development, body composition (fat mass, lean mass and bone mass) and physical condition. The results show higher values of total lean mass, total fat mass and percentage of body fat in the groups with higher BMI in prepubertal girls and pubertal girls (p < .05). In relation to VO 2 max, in the prepubertal group, girls with lower VO 2 max had higher values of total fat mass (p < .05) and percentage of body fat (p < .05). In the pubertal group, girls with lower VO 2 max also showed a higher total fat mass (p < .05). The studied variables account for a 85% and 75.4% of the variance of total bone mineral content and bone mineral density (BMD), respectively. In conclusion, the content and BMD are closely related with muscle mass and sports practice in young females. The amount of fat mass showed no association with bone mass and physical condition has an indirect relationship with bone development.
South African Journal for Research in Sport, Physical Education and Recreation
This study identified the most important parameters for the design and safety of artificial turf ... more This study identified the most important parameters for the design and safety of artificial turf football fields according to professional footballers and coaches. Two semi-structured interviews were conducted. The sample consisted of 32 professional players and 25 professional coaches. The players and coaches emphasised that the main problem with artificial turf was the increased risk of injury. The consensus of the interviewees was that it is essential for artificial turf to be installed gradually in elite competitions, starting with youth football. It would allow players to be slowly acclimatised to the surface through their developmental stages. When they reach elite competitions, they would be able to play comfortably either on natural or artificial turf with fewer problems.
The aim of this study is to learn more about the physical activity habits of participants in a po... more 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.
Proceedings of the Institution of Mechanical Engineers, Part P: Journal of Sports Engineering and Technology, 2014
Football fields of artificial turf are in constant evolution. The resulting improvements have giv... more Football fields of artificial turf are in constant evolution. The resulting improvements have given rise to a large diversity of structural components. There are various types of infill and fibre for artificial turf and different designs and materials for the support structure (sub-base and elastic layer). The design of the sub-base and the presence or absence of the elastic layer can influence turf performance and the surface’s useful lifetime. The aim of this study was to assess in situ the effect of the various support structures on the mechanical properties of artificial turf after deterioration caused by wear for a year. The assessed properties were force reduction (%), standard vertical deformation (mm), rotational traction (N·m), vertical ball rebound (%), and ball roll (m), according to the requirements in norm EN 15330-1:2007. The results demonstrate the effect of the structural base on the mechanical and functional performance of football fields of artificial turf, as well...
The aim of the study was to compare the effects of an in-season five weeks of high-intensity trai... more The aim of the study was to compare the effects of an in-season five weeks of high-intensity training (HIT) with a concurrent HIT eccentric overload training (CT) program on male amateur team-sports players’ fitness performance. Twenty-two athletes were randomly assigned to HIT (n=10) or CT (n=12). Both groups completed a HIT program. The CT group also completed two-three sets of six repetitions of eccentric overload training. Before and after training, performance was assessed for change of direction ability (COD), repeated sprint ability for best time (RSAb), mean time (RSAm) and slowest time (RSAs), jumping, and shuttle-run performance. Within-group analyses in both groups showed substantial better scores on COD, RSAb and RSAm and shuttle-run performance. Between-group analyses showed greater improvements in COD, RSAb, RSAm, RSAs, and jumping after additional CT compared to solely HIT. In conclusion, compared to HIT alone, concurrent eccentric overload and HIT training within the...
The aim of this research was to evaluate the influence of the mechanical properties of artificial... more 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 (22.4461.72 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 (49.4661.75 s vs 47.5561.82 s (S1) and 47.8561.59 s (S2); p,0.001). The performance in jumping tests (countermovement jump and squat jump) and ball kicking to goal decreased after the RSA test in all surfaces assessed (p,0.05), since the artificial turf system did not affect performance deterioration (p.0.05). 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 = 70.83614.28) than on the softer artificial turf system (S2; visual analogue scale = 54.24619.63). 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.
Uploads
Papers by Javier Sánchez