Reliability and usefulness of maximum soccer-specific jump test: a valid and cost-effective system to measure on soccer field.

The aims of this study were (a) to assess intra-session reliability and usefulness of the soccer-specific maximum vertical jump (heading test, HT) and (b) to analyse the validity of the easy-to-use and cost-effective instrument (smartphone camera, MOB) compared with gold-standard instrument (3D motion capture system, MOCAP) to obtain the vertical jump performance during HT. Twelve semi-professional high-level and fifteen amateur soccer male players (23.9 ± 3.6 years) performed three HT attempts, and kinematic data were recorded with MOB and MOCAP. Intra-class correlation coefficient (ICC) and coefficient of variation (CV) were used as measures of intra-session reliability. T-test with Cohen's effect size (ES), Pearson's product moment and Bland-Altman analysis were used to obtain MOB validity. Regarding intra-session reliability, the CV was 1.13%, and ICC was 0.98, considered acceptable. Respecting validity criteria did not reveal significant differences (p < 0.05; effect size = 0.06, considered trivial), 'almost perfect' correlation (Pearson) (r = 0.98; p < 0.05), and strong agreement were obtained between MOB and MOCAP. This finding showed a test (HT) with a specific character, using cost-effective instrument and applicable to all soccer fields (adjusted to the standardised lines in the soccer field), all of them backed-up by reliability, usefulness and validity criteria.

Exercise-Based Training Strategies to Reduce the Incidence or Mitigate the Risk Factors of Anterior Cruciate Ligament Injury in Adult Football (Soccer) Players: A Systematic Review.

Anterior cruciate ligament (ACL) is one of the most concerning injuries for football players. The aim of this review is to investigate the effects of exercise-based interventions targeting at reducing ACL injury rate or mitigating risk factors of ACL injury in adult football players. Following PRISMA guidelines, a systematic search was conducted in CINAHL, Cochrane Library, PubMed, Scopus, SPORTDiscus and Web of Science. Studies assessing the effect of exercise-based interventions in ACL injury incidence or modifiable risk factors in adult football players were included. 29 studies evaluating 4502 male and 1589 female players were included (15 RCT, 8 NRCT, 6 single-arm): 14 included warm-up, 7 resistance training, 4 mixed training, 3 balance, 1 core stability and 1 technique modification interventions. 6 out of 29 studies investigated the effect of interventions on ACL injury incidence, while the remaining 23 investigated their effect on risk factors. Only 21% and 13% studies evaluating risk of injury variables reported reliability measures and/or smallest worthwhile change data. Warm-up, core stability, balance and technique modification appear effective and feasible interventions to be included in football teams. However, the use of more ecologically valid tests and individually tailored interventions targeting specific ACL injury mechanisms are required.

Curve Sprinting in Soccer: Kinematic and Neuromuscular Analysis.

Sprinting in curvilinear trajectories is an important soccer ability, corresponding to ~85% of the actions performed at maximum velocity in a soccer league. We compared the neuromuscular behavior and foot contact-time between outside leg and inside leg during curve sprinting to both sides in soccer players. Nine soccer players (age=23±4.12 years) performed: 3×Sprint linear, 3×Sprint right curve, and 3×Sprint left curve. An ANOVA with repeated measures was used to compare the differences between inside and outside leg, and Cohen's d was used to calculate the effect-size. Considering the average data, the performance classification (from best to worst) was as follows: 1. Curve "good" side (2.45±0.11 s), 2. Linear (2.47±0.13 s), and 3. Curve "weak" side (2.56±0.17 s). Comparing linear with curve sprinting, inside leg recorded significant differences ("good" and "weak"; effect size=1.20 and 2, respectively); in contrast, for outside leg, there were no significant differences ("good" and "weak"; effect size=0.30 and 0.49, respectively). Electromyography activity showed significant differences (p≤0.05) during curve sprinting between outside (higher in biceps femoris and gluteus medius) and inside leg (higher activity in semitendinosus and adductor). In summary, inside and outside leg play different roles during curved sprints, but inside leg is more affected by the change from straight to curve sprint.

Attitudes, beliefs and knowledge related to doping in different categories of football players.

OBJECTIVES: The aim of this study was to study and compare attitudes, beliefs and knowledge about doping of footballers, from elite to under-18 categories. DESIGN: The descriptive exploratory design used an instrument combining a validated questionnaire (Performance Enhancement Attitude Scale: PEAS) with qualitative open-ended questions. METHODS: A total of 1324 Spanish football players (average age 22.56 ± 5.62 years) from 88 football teams that ranged from elite to under-18 categories: Elite (ELI, n = 304), non-elite Professional (PRO, n = 308), top Amateur (AMA, n = 330), elite Under-18 (U18, n = 334) and elite Female (FEM, n = 48) composed the sample. RESULTS: PEAS overall scores (range 17-102, with higher scores representing more permissive attitudes) was 34.02 ± 11.08. The overall scores for all groups analysed were: FEM: 33.75 ± 14.73; ELI: 30.61 ± 9.91; PRO: 34.23 ± 11.13; AMA: 35.05 ± 10.35; and U18: 35.93 ± 11.50. Significant differences were observed between ELI and PRO (p < 0.001), ELI and AMA (p < 0.001), and ELI and U18 (p < 0.001). 95% of participants did not know the meaning of WADA; 97.4% did not know the Prohibited List; 5% admitted having used banned substances and 23.7% knew dopers. CONCLUSIONS: This study showed different an important lack of knowledge about doping and an high levels of supplement use in this sample of footballers assessed. It which clearly reinforces the idea of implementing a wide educational doping prevention programme in football environment.

USEFULNESS OF Β-HYDROXY-Β-METHYLBUTYRATE (HMB) SUPPLEMENTATION IN DIFFERENT SPORTS: AN UPDATE AND PRACTICAL IMPLICATIONS.

INTRODUCTION: although -hydroxy--methylbutyrate (HMB) is generally marketed as a supplement for increasing muscle mass and strength, it is still not fully understood how and in which particular sports and conditions HMB can be more effective. AIMS: the primary purpose of this review is to update and summarize the current knowledge about the usefulness of HMB and to organize this information by different sports with specific reference to sports with high wear and tear phenomena as soccer, rugby or football. METHODS: a search was performed in PubMed database. This review presents the results about HMB use in sport. RESULTS: the articles identified in this review support the notion that HMB could help to attenuate tissue catabolism and initiate muscle anabolism particularly in untrained individuals exposed to strenuous exercise or when trained individual are exposed to periods of high physical stress. HMB could therefore be applied in some specific periods of athlete's season where there are high-intensity training periods, high density of competitions and little recovery time between them, starting recovery phases from an injury period and/or any other different situation where performance or recovery could be affected by a great catabolic environment. CONCLUSION: this update contributes to clarify and define possible mechanisms and/or effectiveness of HMB supplementation related to endurance sports (i.e. cycling and athletics), strength-power sports (i.e. resistance training, football, rugby, soccer, judo, waterpolo and rowing) and recreational activities.

Introducción: aunque el -hidroxi--metilbutirato (HMB) se ha empleado generalmente como suplemento para aumentar la masa muscular y la fuerza, es necesario un mejor entendimiento de su función y averiguar en qué deportes es más efectivo. Objetivos: el objetivo principal de esta revisión es actualizar y resumir el conocimiento existente en torno a la utilización del HMB para clasificarla en función de cada modalidad deportiva, con especial mención a aquellas actividades con un alto grado de destrucción muscular, como pueden ser el fútbol, el rugby o el fútbol americano. Métodos: se utilizó la base de datos PubMed para la búsqueda de artículos. Esta revisión presenta los resultados sobre la utilización de HMB clasificados por deportes. Resultados: la mayoría de los artículos seleccionados sugieren que cuando una persona entrenada o no entrenada se somete a un ejercicio intenso o diferente al habitual, el HMB puede atenuar el catabolismo muscular producido e iniciar los procesos anabólicos necesarios para recuperar lo antes posible. De esta forma, el HMB podría aplicarse en algunos momentos concretos de la temporada deportiva en los que hubiera períodos con entrenamientos de alta intensidad, o durante un periodo con alta densidad competitiva y con poca recuperación entre competiciones, o bien durante las primeras fases de la readaptación física después de una lesión y/o durante cualquier otra situación en la que el rendimiento o la recuperación se pueden ver afectados por un entorno altamente catabólico. Conclusión: esta revisión pretende aclarar y definir los posibles mecanismos por los que la suplementación con HMB puede ser efectiva en deportes de resistencia (ciclismo y carreras de fondo), en deportes de fuerza-potencia (fútbol, yudo, waterpolo, remo, fútbol americano y musculación) y en actividades deportivas recreacionales.

Knowledge, attitudes and beliefs of technical staff towards doping in Spanish football.

The aim of this study was to understand the attitudes, beliefs and knowledge among technical staff members of Spanish football teams regarding doping. The sample was drawn from 88 football teams that ranged from elite to under-18 categories. The 237 stakeholders (34.45 ± 8.59 years) were categorised as follows: coaches (COA) (n = 101), physical trainers (PT) (n = 68) and rest of technical staff (RTS) (n = 68). The descriptive exploratory design used an instrument that combined a validated questionnaire (Performance Enhancement Attitude Scale; PEAS) with specific, qualitative open-ended questions. The overall mean score from the PEAS (range, 17-102, with higher scores representing more permissive attitudes towards doping) was 31.64 ± 10.77; for COA, 31.91 ± 11.42; for PT, 31.28 ± 9.44; and for RTS, 31.58 ± 11.18. Regarding participants' knowledge and beliefs, most respondents (57.6%) did not know the meaning of WADA (World Anti-Doping Agency); 84.9% did not know the prohibited list; and 39.2% had used/recommended supplements. In addition, 87.2% recognised "differential treatment of doping among sports," with cycling considered most affected (62.6%) and team sports least (27.2%, with football at 15%). The dangerous lack of knowledge highlights the necessity for anti-doping education and prevention programs for all football stakeholders, not just athletes.

Cross-cultural adaptation and validation of the spanish version of the performance enhancement attitude scale (petróczi, ).

The aim of the present study was to cross-culturally adapt and validate the Spanish version of the Performance Enhancement Attitude Scale (PEAS). A cross-sectional multi-sample survey with 17 independent datasets was carried out. Cross-cultural adaptation of the PEAS into Spanish was conducted through forward/backward translations, consensus panels and comparative analyses of known-groups to establish evidence for its reliability and validity. Weighted Kappa coefficients with quadratic weighting were used to assess the reliability of each item, with Cronbach's internal consistency coefficients for overall scale's reliability and Spearman's correlation coefficient for test-retest reliability over a one-week period. Confirmatory factor analysis (CFA) was performed to assess the scale's structure. Differences between self-admitted doping users and non-users were analysed to verify the PEAS' construct validity in 8 datasets. Spearman's correlation coefficient was also used to assess the relationships between the PEAS and self-esteem, self-efficacy and perceived descriptive norm to establish convergent validity. The scale showed satisfactory levels of internal consistency (α = 0.71-0.85), reliability of each item (Kappa values range 0.34-0.64) and temporal stability (r = 0.818; p < 0.001). CFA showed acceptable fit (RMSEA <0.08, mean RMSEA = 0.055; χ(2)/df < 3, mean χ(2)/df = 1.89) for all but one samples. As expected, self-admitted doping users showed more positive attitude toward doping than non-users. Significant and strong negative relationship was found between PEAS and self-efficacy; weak negative correlation with self-esteem and and positive correlation with perceived descriptive norm. The Spanish version of PEAS showed satisfactory psychometric properties. Considerations for application and improvement are outlined. Key pointsFirst study that crosses culturally adapted the PEAS to the Spanish language.The Spanish version of PEAS has satisfactory psychometric properties.Users scored higher than non-users indicating a satisfactory construct validity. Significant positive correlation was found between PEAS and projected use.Significant negative correlation between PEAS and self-esteem and self-efficacy.

Does a non-circular chainring improve performance in the bicycle motocross cycling start sprint?

Maximising power output during the initial acceleration phase of a bicycle motocross (BMX) race increases the chance to lead the group for the rest of the race. The purpose of this study was to investigate the effect of non-circular chainrings (Q-ring) on performance during the initial acceleration phase of a BMX race. Sixteen male cyclists (Spanish National BMX team) performed two counterbalanced and randomized initial sprints (3.95s), using Q- ring vs. circular chainring, on a BMX track. The sample was divided into two different groups according to their performance (Elite; n = 8 vs. Cadet; n = 8). Elite group covered a greater distance using Q-ring (+0.26 m, p = 0.02; D = 0.23), whilst the improvement for the Cadet (+0.04 m) was not significant (p = 0.87; D = -0.02). Also, there was no significant difference in power output for the Elite group, while the Cadet group revealed larger peak power with the circular chainring. Neither lactate level, nor heart rate showed significant differences due to the different chainring used. The non-circular chainring improved the initial acceleration capacity only in the Elite riders. Key PointsThis work provides novel results demonstrating very significant improvements in the sprint performance of BMX cycling discipline using a non-circular chainring system.This study seeks a practical application from scientific analysisAll data are obtained in a real context of high competition using a sample comprised by the National Spanish Team.Some variables influencing performance as subjects' physical fitness are discussed.Technical equipment approved by International Cycling Union is studied to check its potentially beneficial influence on performance.

Efecto de un programa de actividad física sobre el rendimiento aeróbico y la fuerza de prensión manual en niños / Effect of a physical activity program on aerobic performance and hand-grip strength in children

La elevada inactividad física provocada por los nuevos estilos de vida es considerada como uno de los principales problemas de salud pública actuales. Aunque tradicionalmente ha sido la capacidad aeróbica la cualidad física más estudiada en relación con la salud, en estos últimos años está surgiendo la evaluación del estado muscular como otro importante indicador de la salud para todas las fases de la vida. Los objetivos de este estudio han sido analizar el consumo de oxígeno máximo (a través de un test indirecto-incremental máximo) y la fuerza muscular (a través de la fuerza de prensión manual) de escolares granadinos, además de evaluar el efecto que provoca una intervención física extraescolar sobre estos parámetros. Un total de 234 alumnos de diversos colegios de Granada (España) con edades comprendidas entre los 10-12 años participaron en el estudio. La intensidad de actividad física se controló mediante el registro de frecuencia cardiaca, para la estimación del VO2maxse utilizó el test Course-Navette y para medir la fuerza muscular se utilizó un dinamómetro manual digital. Se calcularon los estadísticos descriptivos y las diferencias entre variables fueron analizadas mediante la prueba T para muestras independientes y para muestras relacionadas. Los resultados globales mostraron unos niveles de VO2max de 43,49 ± 3,51 ml/kg/min. Los valores generales obtenidos para la fuerza en mano dominante fueron de 19,94 ± 4,07 kg frente a 18,50 ± 3,79 kg obtenidos en mano no dominante. El grupo intervención experimentó mejoras en los valores de VO2max. En cuanto a la fuerza, no se encontraron mejoras estadísticamente significativas. Los resultados del presente estudio mostraron unos niveles óptimos de volumen de oxígeno máximo y de fuerza muscular en la población de escolares granadinos analizada. Del mismo modo, estos datos sugieren la eficacia del programa de intervención de actividad física extraescolar propuesto sobre los parámetros analizados

High physical inactivity caused by the new lifestyles is considered as one of the major public health problems. Traditionally, aerobic capacity has been the most studied physical quality in relation to health, but in recent years it is emerging the muscular condition assessment as another important indicator of health for all stages of life. The aims of this study were to analyze the maximum oxygen intake (VO2max) and muscle strength in students from Granada, and to assess the effect of an extracurricular physical activity program on these parameters. A total of 234 students from different schools of Granada (Spain) aged 10-12years participated in the study. Physical activity was controlled by means of heart rate monitoring. Maximal oxygen uptake (VO2max) was estimated using a 20 meters incremental-maximum shuttle run field test. Hand grip strenght was assessed using a dynamometer. Descriptive statistics were calculated. We performed T tests for independent and related samples to compare aerobic capacity and hand grip strenght. The results show levels in VO2max of 43.49 ± 3.51 ml/kg/min. The values obtained for the dominant hand strength were 19.94 ± 4.07 kg versus 18.5 ± 3.79 kg obtained for no dominant hand. The intervention group experienced improvements in VO2max values. In terms of strength, significant improvements were not found. Results of this study show optimal levels of VO2max as predictor of aerobic capacity and muscle strength in the school population of Granada analyzed. Similarly, these data suggest the effectiveness of the intervention program proposed school physical activity on the parameters analyzed (aerobic capacity and muscle strength)

Opinión y experiencia respecto al dopaje de los directores nacionales de ciclismo españoles / Spanish cycling team managers’ opinion and experience regarding doping

El objetivo del presente estudio fue conocer y comparar las opiniones y experiencias respecto al dopaje de una muestra de directores nacionales de ciclismo españoles teniendo en cuenta su experiencia como ciclistas y su nivel de formación académica previos. Un total de 87 directores nacionales de ciclismo (más alto nivel) participaron en el estudio. Atendiendo a su experiencia ciclista previa, 40 sujetos habían sido ciclistas "profesionales", 29 habían sido ciclistas hasta categoría "Aficionado" mientras que 18 no habían tenido experiencia como ciclistas. En relación a su formación académica, 15 sujetos eran Licenciados en Ciencias del Deporte, 36 poseían una certificación federativa previa y 36 no tenían ninguna formación técnica o académica previa, pero habían sido previamente ciclistas profesionales. Se llevó a cabo un diseño transversal descriptivo mediante un cuestionario específico consistente en 7 preguntas de respuesta libre. Aunque existen diferencias entre los distintos grupos analizados y comparados, en general, la palabra más mencionada asociada al dopaje fue "trampa", los agentes responsables más mencionados fueron "técnicos" y "laboratorios" la diferencia entre ciclismo y otros deportes más destacada fue "trato discriminatorio" y la razón para recurrir al dopaje fue la búsqueda del "éxito deportivo". La mayoría de los participantes reconocen que en alguna ocasión se les ha sugerido doparse y ser conocedores de casos similares. Las soluciones propuestas fueron "prevención temprana" y "aumentar número de controles". Este estudio muestra que los directores nacionales de ciclismo analizados reconocen el fenómeno del dopaje. La comparación intergrupal muestra datos interesantes acerca de aspectos tales como agentes responsables del dopaje y razones para recurrir a esta práctica prohibida. Se observa la reconocida y cercana convivencia con el dopaje, especialmente, desde la perspectiva de los ex ciclistas profesionales. Estos resultados potencian la idea de que, además de mantener controles antidopaje y hacerlos más eficientes, son necesarios programas de educación desde edades más tempranas

The aim of this study was to determine and compare the opinions and experiences regarding doping of a sample of Spanish cycling team managers considering his previous experience as cyclists and their academic level of training. A total of 87 cycling team managers (the highest level) participated in the study. Regarding his previous cycling experience, 40 subjects were cyclists "professionals", 29 had been cycling to category "Amateur" while 18 had no experience as cyclists. In relation to their previous academic level of training, 15 subjects had a degree in Sport Sciences, 36 had prior federal certification and 36 had no prior technical or academic training, but had previously been professional cyclists. Cross-sectional descriptive design was carried out by means of a specific questionnaire comprised of seven open-ended questions. Although there were differences between analyzed and compared groups, in general, the most mentioned word associated with doping was "cheating", the most often mentioned doping agents were "managers" and "laboratories", the highlighted difference between cycling and other sports was "discriminatory treatment" and the main reason for using doping practices was the search for "athletic success". Most participants recognized that they have been suggested to dope and also know similar cases. The main proposals of solution to eradicate doping were "prevention since early ages" and "increase the number of controls". This study shows that Spanish cycling team managers recognize the existence of the phenomenon of doping. The comparison among analized groups shows interesting data about different issues such as responsible agents of doping and reasons for initiation in doping. It was observed a recognized and close coexistence with doping for the total sample, especially from the perspective of former professional cyclists. These results support the idea that, apart from maintaining doping controls and make them more efficient, educational programs since earlier ages are needed

Attitudes towards doping and related experience in Spanish national cycling teams according to different Olympic disciplines.

Attitudes towards doping are considered an influence of doping intentions. The aims of the present study were 1) to discover and compare the attitudes towards doping among Spanish national team cyclists from different Olympic disciplines, as well as 2) to get some complementary information that could better explain the context. The sample was comprised of seventy-two cyclists: mean age 19.67±4.72 years; 70.8% males (n = 51); from the different Olympic disciplines of Mountain bike -MTB- (n = 18), Bicycle Moto Cross -BMX- (n = 12), Track -TRA- (n = 9) and Road -ROA- (n = 33). Descriptive design was carried out using a validated scale (PEAS). To complement this, a qualitative open-ended questionnaire was used. Overall mean score (17-102) was 36.12±9.39. For different groups, the data were: MTB: 30.28±6.92; BMX: 42.46±10.74; TRA: 43.22±12.00; ROA: 34.91±6.62, respectively. In relation to overall score, significant differences were observed between MTB and BMX (p = 0.002) and between MTB and TRA (p = 0.003). For the open-ended qualitative questionnaire, the most mentioned word associated with "doping" was "cheating" (48.83% of total sample), with "responsible agents of doping" the word "doctor" (52,77%), and with the "main reason for the initiation in doping" the words "sport achievement" (45.83%). The major proposed solution was "doing more doping controls" (43.05%). Moreover, 48.67% stated that there was "a different treatment between cycling and other sports". This study shows that Spanish national team cyclists from Olympic cycling disciplines, in general, are not tolerant in relation to doping. BMX and Track riders are a little more permissive towards the use of banned substances than MTB and Road. Results from the qualitative open-ended questionnaire showed interesting data in specific questions. These results empower the idea that, apart from maintaining doping controls and making them more efficient, anti-doping education programs are needed from the earliest ages.

Doping in sport: a review of elite athletes' attitudes, beliefs, and knowledge.

Doping in sport is a well-known phenomenon that has been studied mainly from a biomedical point of view, even though psychosocial approaches are also key factors in the fight against doping. This phenomenon has evolved greatly in recent years, and greater understanding of it is essential for developing efficient prevention programmes. In the psychosocial approach, attitudes are considered an index of doping behaviour, relating the use of banned substances to greater leniency towards doping. The aim of this review is to gather and critically analyse the most recent publications describing elite athletes' attitudes, beliefs and knowledge of doping in sport, to better understand the foundations provided by the previous work, and to help develop practical strategies to efficiently combat doping. For this purpose, we performed a literature search using combinations of the terms "doping", "sport", "elite athletes", "attitudes", "beliefs", "knowledge", "drugs", and "performance-enhancing substances" (PES). A total of 33 studies were subjected to comprehensive assessment using articles published between 2000 and 2011. All of the reports focused on elite athletes and described their attitudes, beliefs and knowledge of doping in sport. The initial reasons given for using banned substances included achievement of athletic success by improving performance, financial gain, improving recovery and prevention of nutritional deficiencies, as well as the idea that others use them, or the "false consensus effect". Although most athletes acknowledge that doping is cheating, unhealthy and risky because of sanctions, its effectiveness is also widely recognized. There is a general belief about the inefficacy of anti-doping programmes, and athletes criticise the way tests are carried out. Most athletes consider the severity of punishment is appropriate or not severe enough. There are some differences between sports, as team-based sports and sports requiring motor skills could be less influenced by doping practices than individual self-paced sports. However, anti-doping controls are less exhaustive in team sports. The use of banned substance also differs according to the demand of the specific sport. Coaches appear to be the main influence and source of information for athletes, whereas doctors and other specialists do not seem to act as principal advisors. Athletes are becoming increasingly familiar with anti-doping rules, but there is still a lack of knowledge that should be remedied using appropriate educational programmes. There is also a lack of information on dietary supplements and the side effects of PES. Therefore, information and prevention are necessary, and should cater to the athletes and associated stakeholders. This will allow us to establish and maintain correct attitudes towards doping. Psychosocial programmes must be carefully planned and developed, and should include middle- to long-term objectives (e.g. changing attitudes towards doping and the doping culture). Some institutions have developed or started prevention or educational programmes without the necessary resources, while the majority of the budget is spent on anti-doping testing. Controls are obviously needed, as well as more efficient educational strategies. Therefore, we encourage sporting institutions to invest in educational programmes aimed at discouraging the use of banned substances. Event organizers and sport federations should work together to adapt the rules of each competition to disincentivize dopers. Current research methods are weak, especially questionnaires. A combination of qualitative and quantitative measurements are recommended, using interviews, questionnaires and, ideally, biomedical tests. Studies should also examine possible geographical and cultural differences in attitudes towards doping.