The Relative Age Effect in the Two Professional Men's Football Leagues in Spain.

The age difference among individuals of the same group is known as Relative Age. Relative Age Effect refers to the consequences derived from it, such as delayed physical, cognitive and mental development of children born later in the year. The aim of this study was to observe the Relative Age Effect by analyzing players' dates of birth throughout three seasons in the two professional football competitions in Spain based on the game positions and the teams' classification at the end of the season. The sample was made up of players (n=4097) from both professional competitions (nLaLiga Santander=1864), and (nLaLiga Smartbank=2233). The data were collected from two public-access football statistics websites. The cut-off date was established on January 1, the year was divided into four quartiles (Q1: January-March, Q2: April-June, Q3: July-September and Q4: October-December). Results confirmed significant differences on dates of births' distribution (p<0.05) for the competitions - LaLiga Santander and LaLiga Smartbank - during three seasons, as well as for player position, with a larger effect observed for goalkeepers and defenders. Significant difference was also observed depending on classification. Results show a clear decreasing percentage of those born in quartile 4 in relation to those born in quartile 1, it can be concluded that the Relative Age Effect phenomenon is present in the Spanish professional football which may lead to an inappropriate talent selection technique in football, with recruitment oriented to the short term, to immediate results, and possibly caused by the early start of the player selection process.

Are Crohn's Disease Patients Limited in Sport Practise? An UltraEndurance Case-Control Study Response.

The aim of this study was to analyze the psychophysiological response of a Crohn's Disease patient in an ultra-endurance event. The psychophysiological responses of a Crohn's Disease and non-Crohn's Disease participant were analysed before during and after an 8 h ultra-endurance running event. Results showed how Crohn's patient presented a similar psychophysiological response than non-Crohn's participant in the ultra-endurance event, except for a higher pre- and post-event sympathetic modulation, lower event sympathetic tone, and lower event body temperature. This study could contribute to improving physical activity recommendations for persons with Crohn's Disease and open a new research line for an improved understanding of psychophysiological modifications of Crohn's Disease patients during exercise.

Airsoft: an efficient and motivating cardiovascular training choice.

BACKGROUND: Obesity and sedentarism have reached pandemic levels, postulating World Health Organization physical exercise as an important key factor for the prevention and treatment. In order to find a motivating and effective physical activity, we conducted this research intending to analyze the physiological and mechanical demands of an airsoft game. METHODS: Cardiovascular and mechanical activity were analyzed by heart rate monitors and GPS in 32 sedentary subjects (27.3±6.2 years; 26.3±7.9 BMI). RESULTS: Participants performed moderate to vigorous aerobic intensity for 3 hours and 20 min of which 55.2% was between 60-70% of their maximal heart rate and 14.2% above 70% of it, turned into distance 9.5 km of which 91.5% was moderate and 8.5% vigorous intensity. CONCLUSIONS: A single airsoft game performed by sedentary subject exceed the international recommendation of physical activity and weekly physical activity of US adults' citizens. This motivating and outdoor activity is an effective alternative to increase the population's physical activity levels.

Psychophysiological respond in a swimming ultra-endurance event.

BACKGROUND: Ultra-endurance events under critical environmental conditions represent unique stress, resulting in acute marked adaptations to the cardiovascular, respiratory, metabolic and neuromuscular systems of the organism. In line with this, no studies in swimming events were found thus far. METHODS: This research aimed to analyze the psychophysiological response of swimmers in an ultra-endurance swimming event. Changes in the rate of perceived exertion, blood lactate concentration, 1000m swimming time and cortical arousal were measured in 19 male volunteer swimmers (28.0±5.6 years; 175.0±7.9 cm; 70.1±7.8 kg) in 3 moments during a 24h swimming event. RESULTS: We found a significant increase in lactate concentration after series 1, decreasing the values in series 2 and series 3. Cortical arousal decreased significantly in series 3 respect the basal sample. Rate of perceived exertion significantly increased in the swimming ultra-endurance event and 1000m swimming time was maintained during the series analyzed. CONCLUSIONS: An ultra-endurance swimming event produced an increase in blood lactate concentration and rated of perceived exertion and a decrease in cortical arousal, not affecting average swimming velocity along the event.

Psychophysiological Stress Response of Novice Cavers in a Speleology Route.

INTRODUCTION: Speleology/Caving is a recreational outdoor activity that has drawn an increasing number of participants in recent years, but there is little information on the physiological and psychological demands of this outdoor activity. This research aimed to analyze the psychophysiological response of novice cavers to a caving route. METHODS: Modifications in autonomic modulation, ratings of perceived exertion, and perceived stress were evaluated in physically active participants before, during, and after a caving route of 3-h duration. RESULTS: Eighteen participants were assessed. We found an anticipatory anxiety response in the participants before starting the route and significant increases in the ratings of perceived exertion, stress perception, autonomous sympathetic modulation as evaluated by heart rate variability while on the route, and sympathetic modulation 30 min after finishing the caving route. CONCLUSIONS: A speleology route produced an anticipatory anxiety response, an increase in the sympathetic stress response, fatigue symptoms at the autonomic nervous system level, and low perception of stress and effort compared with the autonomic stress response. This information could help to better prepare participants for this demanding event, potentially avoiding accidents and injuries and increasing safety for cavers.

The relationship between the relative age effect and performance among athletes in World Handball Championships.

This study examines the relative age effect (RAE) and its impact on the performance of elite male (n = 3,358) and female (n = 3,273) handball players in the U-19 (n = 2,188), U-21 (n = 2,031), and senior (n = 2,412) categories of the 2013/2014, 2015/2016 and 2017/2018 World Handball Championships organised by the International Handball Federation (IHF). The distribution of the players´ birth dates (by quartile: Q, and semester: S) by categories, handball playing positions, and membership of continental federations, were analysed for each of the three two-year periods in which the World Handball Championships took place. Differences between the observed and expected birth dates were tested using a chi-square goodness of fit test, and subsequent calculations were tested using odds ratios. The Spearman's correlation coefficient was applied to test the correlation between the relative age of the athletes and (their) performance parameters. The results revealed a prevalence of the RAE on both male and female in the U-19 and U-21 categories (p<0.001), and a stabilisation of the RAE throughout the period analysed (2013/14-2017/2018). The RAE was not found in the female senior category (2013, 2015 and 2017) or male senior category (2013) (p>0.05). All playing positions were impacted by the RAE (p<0.001), and especially strong effect sizes were noted for male pivots (Vc = 0.66/0.68/0.60) and female center backs (Vc = 0.71/0.65/0.71). In our analysis of the handball continental federations, the RAE was found in all regions, except Oceania (p>0.05). The RAE also affected athlete performance: the oldest athletes played more minutes and achieved better performances. The RAE was associated with the final placement of the teams in each championship category, except in the male youth category. The findings clearly demonstrated that the RAE has a significant impact on the selection of male and female athletes to international competitions and the performance of both men and women in international handball. The potential implications of these findings for policy and practice are discussed.

Psychophysiological and Specific Fine Motor Skill Modifications in a Checkpoint Action.

In last years, the insurgency attacks on task forces bases and checkpoints have been common. The study of psychophysiological response of soldiers in these asymmetrical and non-controlled situations remains a challenge. The present research aimed to analyze the psychophysiological response and the variations in specific fine motor skill after a checkpoint simulation which included surveillance, unexpected attacks, and melee combat. Psychophysiological parameters -heart rate, blood glucose, pressure, oxygen saturation, and lactate, legs´ strength, skin temperature, cortical activation, anxiety-, as well as fine motor skills were analyzed in a sample of 24 professional Spanish Army soldiers (35.67 ± 6.62 years, 177.21 ± 7.37 cm, 82.29 ± 11.02 kg, 26.17 ± 2.82 BMI, 15.25 ± 7.44 years of experience in their unit) before and after a checkpoint simulation. The checkpoint surveillance operation produced a significant increase (p < 0.05) in rated perceived exertion, heart rate, blood lactate concentration, legs´ strength and somatic anxiety, and a significant decrease in blood oxygen saturation and skin temperature values. We concluded that results were consistent with an activation of sympathetic nervous system, triggering a fight-flight response, a chain of intense psychophysiological reactions and a misinterpretation of perceived exertion. Results may help predicting soldiers´ physical and operative behavior in real situations.

The Relative Age Effect in the 10 Best Leagues of Male Professional Football of the Union of European Football Associations (UEFA).

The aim of the present research was to observe the relative age effect on professional soccer players of the ten best leagues of the Union of European Football Associations (UEFA), according to the IFFHS (International Federation of Football History and Statistics). The sample consisted of 5201 professional players who participated in the professional leagues during the 2016-2017 season. The birth date of each player was classified in four quartiles (Q1, Q2, Q3 and Q4). The frequencies (fr) and percentages (%) of the birth quartiles were analyzed. The chi square test (X2) and degrees of freedom (gl) were performed to check the differences in the intergroup distribution. Likewise, odd ratios were calculated for the different quartiles, where Q4 was the reference group according to the different leagues studied, playing positions (goalkeeper, defender, midfielder and forward) and classification (first four places, half-of the table and four last places). To calculate the size of the effect on the nominal variables, the Cramer V test was carried out. The results confirmed a greater representation of players born in Q1 and Q2, indicating statistically significant values (p < 0.05) for all the leagues studied, except in the Eerste Klasse A (Belgium). This significance was repeated for the demarcation variables in the field, with a greater effect in the case of the midfielders. Finally, the RAE also affected the three groups according to teams´ classification. The conclusions confirm the effect of the RAE in the sample studied, which would require a review of the talent selection processes in football in order to balance the chances of success of players born at the end of the year.

Assessment of Psychophysiological Response and Specific Fine Motor Skills in Combat Units.

Soldiers´ training and experience can influence the outcome of the missions, as well as their own physical integrity. The objective of this research was to analyze the psycho-physiological response and specific motor skills in an urban combat simulation with two units of infantry with different training and experience. MATERIAL AND METHODS: psychophysiological parameters -Heart Rate, blood oxygen saturation, glucose and blood lactate, cortical activation, anxiety and heart rate variability-, as well as fine motor skills were analyzed in 31 male soldiers of the Spanish Army, 19 belonging to the Light Infantry Brigade, and 12 to the Heavy Forces Infantry Brigade, before and after an urban combat simulation. RESULTS AND CONCLUSION: A combat simulation provokes an alteration of the psycho-physiological basal state in soldiers and a great unbalance in the sympathetic-vagal interaction. The specific training of Light Infantry unit involves lower metabolic, cardiovascular, and anxiogenic response not only previous, but mainly after a combat maneuver, than Heavy Infantry unit's. No differences were found in relation with fine motor skills, improving in both cases after the maneuver. This fact should be taken into account for betterment units´ deployment preparation in current theaters of operations.

Respuesta fisiológica de una unidad paracaidista en combate urbano / Physiological Response of a Paratrooper Unit in Urban Combat

Antecedentes y objetivos: La investigación específica en el ámbito militar se ha centrado tradicionalmente en el efecto del estrés de combate y el desarrollo de patologías como el desorden de estrés postraumático. Las unidades paracaidistas son considerados cuerpos de élite por ser una de las más operativas y por su forma especial de despliegue, realizando la incursión en la zona de operaciones mediante un salto paracaidista. Los actuales escenarios bélicos, se caracterizan por su asimetría y por producirse en entornos urbanos. La respuesta orgánica en situaciones de combate urbano ha sido poco estudiada en la literatura específica a pesar de su importancia para el entrenamiento e instrucción específica, por lo que se planteó como objetivo de la presente investigación analizar la respuesta fisiológica de una unidad paracaidista durante una simulación de combate en población. Material y métodos: Se analizó la frecuencia cardiaca, lactato sanguíneo y percepción subjetiva de esfuerzo en 12 hombres (29,9±5,5 años) paracaidistas del Ejército de Tierra Español antes y después de realizar una simulación de combate urbano. La simulación venía precedida de un salto automático en paracaídas desde una torre de entrenamiento. Resultados: Después de la simulación, los sujetos mostraron un aumento significativo (p<0,05) en los valores de lactato (1,26±0,20 mmol/l vs. 2,56±0,45mmol/l) y de frecuencia cardiaca (38,79±3,13 % vs 75,8±7,08% FC max.). Conclusiones: El análisis de los datos muestra como una simulación de combate provoca un incremento de los valores de lactato sanguíneo con respecto al valor basal, situándolo en valores de umbral aeróbico. La unidad paracaidista realizó esta simulación a una intensidad del 75% de la frecuencia cardiaca máxima y con una concentración de lactato sanguíneo de 2.6 mmol/l. El aumento de los valores de lactato y frecuencia cardiaca durante la simulación puede ser debido a la activación de mecanismos de defensa del cuerpo humano (sistema nervioso simpático)

Background and objectives: Specific research in military field has traditionally been focused on the effect of combat stress and the development of diseases such as post-traumatic stress disorder. Paratroopers units are considered as elite corps as one of the most operative and due to their special way of deployment, making the foray into the area of operations by mean of a parachute jump. Current war theatres are characterized by their asymmetry and for taking place in urban areas. The organic military response in urban combats has been little studied in specific literature despite its importance for training and specific instruction, for this reason, the objective of the present study was to analyze the physiological response of a paratrooper unit during a simulation urban combat. Material and Methods: Heart Rate, Blood Lactate and rated of perceived exertion, were analyzed before and after a simulated urban combat in 12 paratroopers of the Spanish Army. The simulated action was preceded by an automatic parachute jump from a training platform. Results: After the simulation, subjects showed a significant increase (p <0.05) in the values of lactate (1.26 ± 0.20 mmol/l vs. 2.56±0.45 mmol/l) and heart rate (38.79±3.13% vs. 75.80±7.08 FC max.). Conclusions: The paratrooper unit conducted a simulation of combat and an aerobic threshold at 75% of maximum heart rate and blood lactate concentration of 2.6mmol/l were reached. The increase in the lactate and heart rate values after the simulation may be due to the activation of the body defense mechanisms ́ (sympathetic nervous system)

Effect of Parachute Jump in the Psychophysiological Response of Soldiers in Urban Combat.

The study of organic and psychological response during combat situations has been poorly reported despite its importance for soldiers training and specific instruction, so it was proposed as aim of the present investigation to analyze the effect of a tactical parachute simulated jump in psycho-physiological response of paratroopers' warfighters during an urban combat simulation. 19 male paratroopers (31.9 ± 6.2 year old; 173.6 ± 5.3 cm; 73.8 ± 8.3 Kg) of the Spanish Army were divided in two groups: parachute jump group (n:11) that conducted a simulated parachute jump and a urban combat maneuver and a non-parachute jump group (n:8) that only conducted an urban combat maneuver. We analyzed before and after the maneuver the rated perceived exertion, legs strength manifestation, blood lactate, cortical activation, heart rate variability, blood oxygen saturation and pressure, skin temperature, fine motor skills, and anxiety state. A tactical parachute simulated jump prior to an urban combat maneuver produce significantly (p < 0.05) higher heart rate and decrease in specific fine motor skills in comparison with no jump situation in professional Army paratroopers. Independently of the parachute jump, an urban combat maneuver produces a significant increase in rated perceived exertion, blood lactate, heart rate, legs strength, sympathetic modulation and anxiety response as well as a significant decrease in blood oxygen saturation and parasympathetic modulation.