Avaliação do equilíbrio de jogadores de futebol

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Efeito do consumo agudo de erva mate sobre o rendimento fisíco em esteira ergométrica e indicadores metabólicos da exaustão em jogadores profissionais de futebol

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Efeito da suplementação de erva mate (Ilex paraguariensis) sobre a capacidade antioxidante total em atletas futebolistas em teste exaustivo em esteira

Introduction: Physical exercise are related to high oxygen consumption, leading to increase on reactive oxygen species (ROS) generation and subsequent oxidative stress. Concomitantly, physical training can improve the antioxidant defense systems, reducing the deleterious activity of ROS. The yerba mate (Ilex paraguariensis) has several bioactive compounds in its composition, providing important antioxidant activity in improving defense systems and reducing the damage caused by ROS. Few studies related to yerba mate with antioxidant effects during exercise. Objective: Evaluate whether the consumption-based drink yerba mate (Ilex paraguariensis) is able to increase the total antioxidant performance (TAP) after an exhaustive test on a treadmill. Methods: The sample counted with 15 female soccers players from Botucatu-SP female soccer team with a mean age of 22.1 ± 4.2 years. For laboratory tests , it was evaluated: triglycerides (TG), total cholesterol (TC) and fractions, glucose and gamma-GT were dosed by dry chemistry (Vitros® System, Johnson & Johnson). LDL-cholesterol was obtained by Friedwald formula. Total antioxidant performance (TAP) was obtained by the method of fluorescence assay for the measurement of plasma. Weight, height and body mass index (IMC) were measured, percentage of body fat was obtained by bioeletrical impedance analysis (Biodinâmics, modelo 450, USA). Arterial blood pressure was checked by auscultatory method and cardiorespiratory fitness was determined by ergoespirometric test (Ramp Protocol). Maltodextrin was supplemented (30 g in 400 ml) 30 minutes after M0 with placebo (400 ml) or mate (5 g in 400 ml of water). Statistical analysis: ANOVA for repeated measures followed by Tukey's test set, p<0.05. Results: There was a decrease in the pH after exhaustive testing for water and tea (p<0.0001), the same was observed for bicarbonate (p<0.0001). In both groups pO₂ increased for ...

Perfil antropométrico, aptidão motora e aeróbia de jogadores de futebol profissionais e juniores de Trinidad e Tobago

There is little information on Caribbean soccer players. Thus, the aim this study was to descriptive and to compare the anthropometric, motor and aerobic fitness profile between Trinidad and Tobago team professional and junior soccer players. Twenty six soccer players were evaluated (14 professional and 12 junior): anthropometric (height, body mass, BMI, body fat percent), flexibility (sit and reach), velocity (30 m), explosive strength (horizontal and vertical jump), anaerobic power (maximum, mean and minimum power, index of fatigue) and maximum aerobic power. Student Test-t to independent sample was used in statistical analyzes, considering 5% of significance (p<0,05). Results of professional and junior players were, respectively: height (180,6 ± 8,1; 175,0 ± 6,9 cm), body mass (77,1 ± 7,5; 70,6 ± 8,7 kg); BMI (23,6 ± 1,5 / 23,0 ± 1,6 kgm 2 ); body fat (11,9 ± 1,7; 11,6 ± 1,2 %); sitting and reaching (24,9 ± 10,3; 24,9 ± 7,7 cm); velocity (30 m) (4,61 ± 0,14; 4,66 ± 0,15 s); horizontal jump (263,4 ± 14,9; 239,7 ± 12,1 cm); vertical jump (58,7 ± 4,3; 54,6 ± 6,6 cm); maximum power (7,9 ± 0,9; 6,6 ± 0,8 w∙kg-1 ); mean power (6,5 ± 0,7; 5,4 ± 0,9 w∙kg-1 ); minimum power (5,3 ± 0,7; 4,3 ± 1,1 w∙kg-1 ); index of fatigue (33,0 ± 7,9; 34,8 ± 12,8 %); aerobic power (55,0 ± 3,2; 57,2 ± 4,8 ml∙kg-1 ∙min-1 ). Professional players presented higher horizontal jump and maximum, mean and minimum anaerobic power in comparing to the junior players. The highest values of power tests for the lower limbs may be relationship to the longer time of practice in the modality of professional players, which can also indicate a higher level of specialization, which gives priority to the training of power (force and velocity).

Comparison of anaerobic threshold, oxygen uptake and heart rate between specific table

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

ACUTE EFFECTS OF A WARM-UP INCLUDING ACTIVE, PASSIVE, AND DYNAMIC STRETCHING ON VERTICAL JUMP PERFORMANCE

Carvalho, FLP, Carvalho, MCGA, Simao, R, Gomes, TM, Costa, PB, Neto, LB, Carvalho, RLP, and Dantas, EHM. Acute effects of a warm-up including active, passive, and dynamic stretching on vertical jump performance. J Strength Cond Res 26(9): 2447-2452, 2012-The purpose of this study was to examine the acute effects of 3 different stretching methods combined with a warm-up protocol on vertical jump performance. Sixteen young tennis players (14.5 +/- 2.8 years; 175 +/- 5.6 cm; 64.0 +/- 11.1 kg) were randomly assigned to 4 different experimental conditions on 4 successive days. Each session consisted of a general and specific warm-up, with 5 minutes of running followed by 10 jumps, accompanied by one of the subsequent conditions: (a) Control Condition (CC)-5 minutes of passive rest; (b) Passive Stretching Condition (PSC)-5 minutes of passive static stretching; (c) Active Stretching Condition (ASC)-5 minutes of active static stretching; and (d) Dynamic Stretching Condition (DC)-5 minutes of dynamic stretching. After each intervention, the subjects performed 3 squat jumps (SJs) and 3 countermovement jumps (CMJs), which were measured electronically. For the SJ, 1-way repeated measures analysis of variance (CC x PSC x ASC x DC) revealed significant decreases for ASC (28.7 +/- 4.7 cm; p = 0.01) and PSC (28.7 +/- 4.3 cm; p = 0.02) conditions when compared with CC (29.9 +/- 5.0 cm). For CMJs, there were no significant decreases (p > 0.05) when all stretching conditions were compared with the CC. Significant increases in SJ performance were observed when comparing the DC (29.6 +/- 4.9 cm; p = 0.02) with PSC (28.7 +/- 4.3 cm). Significant increases in CMJ performance were observed when comparing the conditions ASC (34.0 +/- 6.0 cm; p = 0.04) and DC (33.7 +/- 5.5 cm; p = 0.03) with PSC (32.6 +/- 5.5 cm). A dynamic stretching intervention appears to be more suitable for use as part of a warm-up in young athletes.

Soccer attenuates the asymmetry of rectus abdominis muscle observed in non-athletes

[EN] PURPOSE: To determine the volume and degree of asymmetry of the rectus abdominis muscle (RA) in professional soccer players. METHODS: The volume of the RA was determined using magnetic resonance imaging (MRI) in 15 professional male soccer players and 6 non-active male control subjects. RESULTS: Soccer players had 26% greater RA volume than controls (P<0.05), due to hypertrophy of both the dominant (28% greater volume, P<0.05) and non-dominant (25% greater volume, P<0.01) sides, after adjusting for age, length of the RA muscle and body mass index (BMI) as covariates. Total volume of the dominant side was similar to the contralateral in soccer players (P = 0.42) and in controls (P = 0.75) (Dominant/non-dominant = 0.99, in both groups). Segmental analysis showed a progressive increase in the degree of side-to-side asymmetry from the first lumbar disc to the pubic symphysis in soccer players (r = 0.80, P<0.05) and in controls (r = 0.75, P<0.05). The slope of the relationship was lower in soccer players, although this trend was not statistically significant (P = 0.14). CONCLUSIONS: Professional soccer is associated with marked hypertrophy of the rectus abdominis muscle, which achieves a volume that is 26% greater than in non-active controls. Soccer induces the hypertrophy of the non-dominant side in proximal regions and the dominant side in regions closer to pubic symphysis, which attenuates the pattern of asymmetry of rectus abdominis observed in non-active population. It remains to be determined whether the hypertrophy of rectus abdominis in soccer players modifies the risk of injury.

Prevalencia del síndrome de burnout en tenistas según su orientación motivacional

[ES] El objetivo de este trabajo ha sido determinar el nivel de burnout en un grupo de tenistas de alto rendimiento y conocer la relación existente entre la orientación motivacional y los niveles de burnout, así como la influencia de las variables sociodemográficas.

Direction detection thresholds of passive self-motion in artistic gymnasts

In this study, we compared direction detection thresholds of passive self-motion in the dark between artistic gymnasts and controls. Twenty-four professional female artistic gymnasts (ranging from 7 to 20 years) and age-matched controls were seated on a motion platform and asked to discriminate the direction of angular (yaw, pitch, roll) and linear (leftward–rightward) motion. Gymnasts showed lower thresholds for the linear leftward–rightward motion. Interestingly, there was no difference for the angular motions. These results show that the outstanding self-motion abilities in artistic gymnasts are not related to an overall higher sensitivity in self-motion perception. With respect to vestibular processing, our results suggest that gymnastic expertise is exclusively linked to superior interpretation of otolith signals when no change in canal signals is present. In addition, thresholds were overall lower for the older (14–20 years) than for the younger (7–13 years) participants, indicating the maturation of vestibular sensitivity from childhood to adolescence.

Das offene Selbstgespräch des Teampartners - Einfluss auf die wahrgenommene Kompetenz und die eigene Anstrengungsbereitschaft

Einleitung und Fragestellung In der Forschung zum Selbstgespräch im Sport dominiert die Frage nach dessen Wir-kung auf die Leistung. Der Einfluss des während der Leistungserbringung geäußerten Selbstgesprächs auf (un-)beteiligte Personen (z.B. Zuschauer, Gegenspieler oder Dop-pelpartner) wurde bislang kaum untersucht. Van Raalte, Brewer, Cornelius und Petitpas (2006) konnten immerhin zeigen, dass Zuschauer einen Tennisspieler als kompetenter einschätzen, wenn er in einem Laborexperiment mit positivem statt mit negativem Selbst-gespräch gezeigt wurde. In unserer Studie stehen Dyaden im Zentrum, in der eine Person eine andere beobach-tet, die mit sich selbst spricht. Untersucht wird, ob bei einer additiven Teamaufgabe sol-che Beobachtungen einen Effekt auf die Kompetenzeinschätzung und die Anstren-gungsbereitschaft haben. Es wird vermutet, dass die beobachtende Person dann eine höhere Anstrengungsbereitschaft (AV) zeigt, wenn sie einen Teampartner mit positivem Selbstgespräch (UV) beobachtet, da sie ihren Partner als kompetenter einschätzt und diese Einschätzung als Mediator wirkt. Methode Es wurde ein randomisierter Zweigruppen-Versuchsplan mit zwei Experimentalgruppen (je n=20) durchgeführt. Das Treatment bestand aus einem Video, das den (jeweils identi-schen) Teampartner bei der Bewältigung der zu absolvierenden visuomotorisch-koordinativen Testaufgabe zeigt (Test 2HAND des Wiener Testsystems). Das Video wur-de abhängig von der Gruppenzugehörigkeit mit negativen respektive positiven Selbstge-sprächsaussagen unterlegt. Die Mediatorvariable wahrgenommene Kompetenz wurde mittels eines Fragebogens erhoben, der in Anlehnung an Van Raalte et al. (2006) entwi-ckelt wurde. Das Vorgehen zur Erhebung der abhängigen Variable Anstrengungsbereit-schaft wurde von Ohlert (2009) übernommen: Die Probanden erhielten die Möglichkeit, sich auf die spätere Testphase vorzubereiten. Erfasst wurde dabei die Zeit, die sie für die Vorbereitung in Anspruch nahmen, und die Genauigkeit, mit der sie eine Reihe von Aufwärmaufgaben absolvierten. Ergebnisse Die Datenerhebung wurde soeben abgeschlossen. Die Ergebnisse der noch ausstehen-den regressionsanalytischen Auswertung werden auf der Tagung präsentiert. Literatur Ohlert, J. (2009). Teamleistung. Social Loafing in der Vorbereitung auf eine Gruppenaufgabe. Hamburg: Dr. Kovac. Van Raalte, J. L., Brewer, B. W., Cornelius, A. E. & Petitpas, A. J. (2006). Self-presentational effects of self-talk on perceptions of tennis players. Hellenic Journal of Psychology, 3, 134-149.

Das offene Selbstgespräch in Dyaden: Dessen Zusammenhang mit Selbstdarstellungstendenzen und Einfluss auf den Partner

Ausgangslage und Fragestellung In der Forschung zum Selbstgespräch im Sport dominiert die Frage nach dessen Auswir-kungen auf die sprechende Person selber. Gemäss Diaz (1992) besitzt das offene Selbstgespräch aber neben der individuell-regulatorischen auch eine sozial-kommunikative Funktion. Diese sozial-kommunikative Funktion und der damit verbunde-ne Einfluss des Selbstgesprächs auf Beobachter wurden in der Sportwissenschaft bisher nur marginal untersucht (z.B. Gould & Weiss, 1981; Van Raalte, Brewer, Cornelius & Pe-titpas, 2006). Im angestrebten Forschungsvorhaben sollen zwei Fragen geklärt werden: Steht das of-fene, während dem Wettkampf geäusserte Selbstgespräch eines Athleten in Zusammen-hang mit dessen Selbstdarstellung? Beeinflusst das offene Selbstgespräch eines Athle-ten den Dyadenpartner und wie sie sich gegenseitig wahrnehmen? Methode Es werden Doppelpartien im Badminton per Videokamera aufgezeichnet. Mittels einer Korrelationsanalyse soll überprüft werden, ob die so erhobenen Selbstgesprächsaussa-gen mit dem Persönlichkeitsmerkmal „Selbstdarstellung“ der Probanden zusammenhän-gen. Nach Spielschluss werden die Probanden entsprechend eines video-stimulierten Fremdkonfrontationsinterviews mit Spielausschnitten konfrontiert, die offenes Selbstge-spräch ihres Dyadenpartners enthalten. Sie werden dabei nach ihren Kognitionen sowie Emotionen gefragt, die sie während der entsprechenden Spielsituation erlebten. Aktuelle Fragen Welcher Fragebogen zur Erhebung des Persönlichkeitsmerkmals „Selbstdarstellung“ soll Verwendung finden? Zur Auswahl steht ein noch zu übersetzender, validierter, engli-scher und sportspezifischer Fragebogen und die Verwendung eines deutschen Frage-bogens, der habituelle Selbstdarstellungstechniken im Allgemeinen erhebt. Wie soll beim video-stimulierten Fremdkonfrontationsinterview vorgegangen werden? Werden den Probanden z.B. das ganze Spiel oder nur ausgewählte Ausschnitte gezeigt, in denen offenes Selbstgespräch vorkommt? Wie zeitnah muss das Interview durchge-führt werden? Literatur Diaz, R. M. (1992). Methodological Concerns in the Study of Private Speech. In R. M. Diaz & L. E. Berk (Eds.), Private speech. From social interaction to self-regulation (pp. 55-81). Hillsdale, NJ: Lawrence Erlbaum. Gould, D. & Weiss, M. (1981). The effects of model similarity and model talk on self-efficacy and muscular endurance. Journal of Sport Psychology, 3, 17-29. Van Raalte, J. L., Brewer, B. W., Cornelius, A. E. & Petitpas, A. J. (2006). Self-presentational effects of self-talk on perceptions of tennis players. Hellenic Journal of Psychology, 3, 134-149.

Os (des)caminhos de um pesquisador do futebol brasileiro

The research in professional football within the human and social sciences, despite increased, still faced limitations and restrictions imposed by the clubs, hindering its realization. As part of my master's thesis, this article aims to portray the effects of leadership on the functioning of the group and to detect the importance and necessity of cohesion in a professional team of footballers. Furthermore, the relationship between the researcher and the football club was analyzed and described, as well as the limitations and obstacles encountered during field research. Following the guidelines of qualitative research and having social psychology as a theoretical background (Kurt Lewin and Pichon-Rivière), this research resulted from the analysis of a professional football club (players, staff and executives of a club with national and international importance) during 5 days of daily contact with the group in games, practice, concentration and meals. The difficulties in analyzing the group's leadership and cohesion were vast, among which stand out the difficulty or impossibility of access to the places-situations suggested as methodology, their refusals to interviews and rejection of the administration of a free choice test. The bond created and the roles taken harmed attempts for further analysis. Therefore, due to the characteristics of contemporary football, especially the financial and political interests the difficulties likely to arise range according to the characteristics of the institution

Os (des)caminhos de um pesquisador do futebol brasileiro

The research in professional football within the human and social sciences, despite increased, still faced limitations and restrictions imposed by the clubs, hindering its realization. As part of my master's thesis, this article aims to portray the effects of leadership on the functioning of the group and to detect the importance and necessity of cohesion in a professional team of footballers. Furthermore, the relationship between the researcher and the football club was analyzed and described, as well as the limitations and obstacles encountered during field research. Following the guidelines of qualitative research and having social psychology as a theoretical background (Kurt Lewin and Pichon-Rivière), this research resulted from the analysis of a professional football club (players, staff and executives of a club with national and international importance) during 5 days of daily contact with the group in games, practice, concentration and meals. The difficulties in analyzing the group's leadership and cohesion were vast, among which stand out the difficulty or impossibility of access to the places-situations suggested as methodology, their refusals to interviews and rejection of the administration of a free choice test. The bond created and the roles taken harmed attempts for further analysis. Therefore, due to the characteristics of contemporary football, especially the financial and political interests the difficulties likely to arise range according to the characteristics of the institution

Os (des)caminhos de um pesquisador do futebol brasileiro

The research in professional football within the human and social sciences, despite increased, still faced limitations and restrictions imposed by the clubs, hindering its realization. As part of my master's thesis, this article aims to portray the effects of leadership on the functioning of the group and to detect the importance and necessity of cohesion in a professional team of footballers. Furthermore, the relationship between the researcher and the football club was analyzed and described, as well as the limitations and obstacles encountered during field research. Following the guidelines of qualitative research and having social psychology as a theoretical background (Kurt Lewin and Pichon-Rivière), this research resulted from the analysis of a professional football club (players, staff and executives of a club with national and international importance) during 5 days of daily contact with the group in games, practice, concentration and meals. The difficulties in analyzing the group's leadership and cohesion were vast, among which stand out the difficulty or impossibility of access to the places-situations suggested as methodology, their refusals to interviews and rejection of the administration of a free choice test. The bond created and the roles taken harmed attempts for further analysis. Therefore, due to the characteristics of contemporary football, especially the financial and political interests the difficulties likely to arise range according to the characteristics of the institution

Regulación del movimiento y anticipación en el resto del primer servicio en tenis

Aunque se han logrado importantes avances en estudios de laboratorio con diseños experimentales poco representativos (e.g., Farrow y Reid, 2012; Nieminen, Piirainen, Salmi, y Linnamo, 2013), a día de hoy, todavía se desconoce a cabalidad cómo los jugadores de tenis de diferente nivel de pericia calibran o ajustan sus movimientos a las demandas espacio-temporales presentes en la tarea de resto de un primer servicio. ! Escasos trabajos se han llevado a cabo in situ y a la mayoría se les puede cuestionar algún aspecto de la metodología empleada. Así pues, en varios estudios la frecuencia de grabación ha sido limitada (e.g., a 50 Hz en Jackson y Gudgeon, 2004; Triolet, Benguigui, Le Runigo y Williams, 2013), o la velocidad del saque ha sido visiblemente inferior a la habitual (cf. Carboch, Süss y Kocib, 2014; Williams, Singer y Weigelt, 1998). También, en algunos estudios los participantes experimentados no han sido jugadores de nivel internacional (e.g., Avilés, Ruiz, Sanz y Navia, 2014), y el tamaño muestral ha sido muy pequeño (e.g., Gillet, Leroy, Thouvarecq, Mégrot y Stein, 2010). ! Además, en los diferentes trabajos se han utilizado una diversidad de métodos e instrumentos de medida y los criterios de codificación del inicio de los movimientos y de las respuestas han diferido; como consecuencia el lapso visomotor de respuesta (LVMr) ha sido muy dispar variando considerablemente de 198 a 410 ms. Considerando los inconvenientes señalados anteriormente, el presente estudio tuvo como objetivo determinar un modelo técnico de regulación temporal de los movimientos y de la respuesta del restador, tomando en cuenta el flujo continuo de información proporcionado por el sacador. Para ello, se realizó un análisis cronométrico de los restos de doce jugadores de diferente nivel deportivo (seis internacionales y seis nacionales) que respondieron de forma natural enviando sus devoluciones hacia las dianas. Se grabaron las acciones de los restadores y sacadores con una cámara Casio Exilim Pro Ex-F1 de alta velocidad (300 Hz) y luego se realizó un análisis imagen por imagen cada 3.33 ms. Una vez obtenidos los datos de los vídeos se realizaron análisis con las pruebas de ANOVA de un factor, ANCOVA con la velocidad del saque como covariable, U de Mann-Whitney y Chi-cuadrado de Pearson. En cuanto a la regulación del movimiento hasta el momento del despegue, los jugadores internacionales iniciaron sus acciones antes que los jugadores nacionales lo que podría indicar una mejor preparación al ejecutar los movimientos como reflejo del nivel de pericia. Los jugadores internacionales iniciaron la elevación del pie posterior a -293 ms y los jugadores nacionales a -202 ms. Todas estas acciones se fueron enlazando unas con otras y fue en el momento del impacto del sacador donde los restadores demostraron una remarcable coordinación perceptivo-motriz. Por consiguiente, los jugadores internacionales despegaron e iniciaron el vuelo a tan solo -6.5 ms del impacto y los jugadores nacionales lo hicieron más tarde a +19.5 ms. A lo largo de la secuencia temporal, todo parece indicar que las informaciones que utilizan los restadores interactúan entre sí; información más temprana y menos fiable para anticipar o moverse antes e información más tardía y más fiable para regular la temporalización de las acciones. Los restadores de nivel internacional y nacional anticiparon a nivel espacial en un bajo porcentaje (7.7% vs. 13.6%) y en tiempos similares (-127 vs. -118 ms) sugiriendo que la utilización de variables ópticas tempranas y menos fiables solo se produce en contadas ocasiones. Por otra parte, estos datos se relacionan con una gran precisión en la respuesta ya que tanto los jugadores internacionales como los nacionales demostraron un alto porcentaje de acierto al responder (95.4% vs. 96.7%). Se había señalado que los jugadores internacionales y nacionales se diferenciarían en el tiempo de caída (i.e., aterrizaje) del primer pie del salto preparatorio, sin embargo ese efecto no fue encontrado (128 vs. 135 ms). Tampoco se hallaron diferencias en el porcentaje de caída con el pie contrario a la dirección de la pelota (58% vs. 62%). Donde sí ambos grupos se diferenciaron fue en el tiempo de caída del segundo pie (147 vs. 168 ms). Esta diferencia de 21 ms fue crucial y fue una prueba de la mayor rapidez de los jugadores internacionales; sugiriendo que ésta acción se podría relacionar con el momento del inicio de la respuesta. Aunque los jugadores internacionales hayan demostrado ser más rápidos en relación con sus capacidades funcionales, ambos grupos no se diferenciaron en todas las variables relacionadas con el LVMr. Ellos no utilizaron esos valiosos milisegundos ganados en el instante de la caída del segundo pie para responder más pronto, ya que el LVMr del miembro superior fue el mismo para ambos grupos (179 vs. 174 ms). Es como si hubiesen tenido todo el tiempo del mundo para seguir ajustando sus acciones hasta el propio golpeo. Además, estos tiempos largos sugieren que en la gran mayoría de los restos la información clave que determinó la respuesta fue detectada (extraída) en momentos cercanos al golpeo del sacador y en la primera parte del vuelo de la pelota. Asimismo, se constató que en general el LVMr se ve influenciado por el tipo de información utilizada. De esta manera, cuando se tomaron en cuenta los ensayos en los que hubo anticipación espacial reflejados en el LVMr del cuerpo entero los tiempos disminuyeron (152 vs. 136 ms). Por otra parte, existieron ocasiones (13%) en los que tanto los jugadores internacionales como los nacionales respondieron tarde recibiendo saques directos (208 vs. 195 ms). Es muy posible que en estos casos los jugadores hayan tenido problemas para detectar la información respondiendo fuera de los márgenes temporales de acción lo que mermó su rendimiento. Lo mismo pudo haber ocurrido cuando ambos grupos de jugadores corrigieron el movimiento del miembro superior tras el impacto (17% vs. 10%) lo que aumentó el tiempo en responder al redirigir la respuesta hacia el lado correcto (208 vs. 205 ms). Además, los jugadores internacionales obtuvieron tiempos de movimiento menores que el de los jugadores nacionales (509 vs. 531 ms) lo que se reflejó en un tiempo total de actuación menor (683 vs. 703 ms). Por último, en cuanto al rendimiento del resto, los jugadores internacionales obtuvieron valores superiores a los jugadores nacionales (1.3 vs. 0.9). ABSTRACT Although there have been significant advances in laboratory studies with unrepresentative experimental designs (e.g., Farrow y Reid, 2012; Nieminen, Piirainen, Salmi, y Linnamo, 2013), today it is still unknown to full extent how tennis players of different levels of expertise calibrate or adjust their movements to the spatial-temporal demands present in the return of a first serve. Few studies have been carried out in situ and some aspects of the methodology most of them used can be questioned. Thus, in several studies the recording frequency has been limited (e.g., a 50 Hz en Jackson y Gudgeon, 2004; Triolet, Benguigui, Le Runigo y Williams, 2013), or serve speed was visibly lower than the usual one (cf. Carboch, Süss y Kocib, 2014; Williams, Singer y Weigelt, 1998). Also, in some studies, experienced participants have not played at international level (e.g., Avilés, Ruiz, Sanz y Navia, 2014), and the sample size has been very small (e.g., Gillet, Leroy, Thouvarecq, Mégrot y Stein, 2010). Furthermore, different works have used a variety of methods and measurement instruments and coding criteria of the onset of movements and responses have differed; due to this, visuomotor response delay (LVMr) has been very uneven, varying considerably from 198-410 ms. Considering the drawbacks mentioned above, this study aimed to determine a technical model of temporal regulation of movements and returner’s response, taking into account the continuous flow of information provided by the server. For this, a chronometric analysis of the returns of twelve players (six international and six national) of different sports level, that naturally responded by hitting their returns towards the targets, was performed. Actions of servers and returners were recorded with a Casio Exilim Pro Ex-F1 high speed camera (300 Hz) and then every 3.33 ms analysis was made frame by frame. Once the data of the videos were obtained, analyses were performed using one factor ANOVA test, ANCOVA with the speed of the serve as a covariate, U of Mann- Whitney and Pearson’s Chi-square test. As for the regulation of movement until the moment of serve, international players began their actions before national players, which could indicate that they were better prepared to execute movements reflecting the level of their expertise. International players began raising the rear foot at -293 ms and national players at -202 ms. All these actions were being linked to each other and it was at the moment of impact of the server when the receivers demonstrated a remarkable perceptual-motor coordination. Therefore, international players took off and started their flight just -6.5 ms before the serve and national players did the same somewhat later: +19.5 ms after the serve. Along the timeline, everything seems to indicate that the information used by returners interact with each other; early information which is less reliable to anticipate or move before, and later information more reliable appears to regulate the timing of actions. Returners of international and national levels anticipated at spatial level in a low percentage (7.7% vs. 13.6%) and in similar times (-127 vs. -118 ms) suggesting that the use of early and less reliable optical variables is only produced on rare occasions. Moreover, these data relate to a precise response as both international and national players showed a high percentage of success in responding (95.4% vs. 96.7%). It had been noted that international and national players would differ in the time the fall (i.e., landing) of the first foot of the split-step, however, this effect was not found (128 vs. 135 ms). No differences in the percentage of fall with the opposite foot to the direction of the ball (58% vs. 62%) were found. Where the two groups differed was in the time of the fall of the second foot (147 vs. 168 ms). This difference of 21 ms was crucial and it was a proof of mayor speed of international players; suggesting that this action could be related to the onset time of response. Although international players have proven to be faster in relation to their functional capabilities, both groups did not differ in all variables related to LVMr. They did not use those precious milliseconds earned at the time of the fall of the second foot to respond as soon, since the LVMr of the upper limb was the same for both groups (179 vs. 174 ms). It is as if they had all the time in the world to continue to adjust their actions until the return itself. Furthermore, these long times suggest that in the vast majority of the returns, key information that determined the response was detected (pick-up) in moments close to the hit of the server and in the first part of the ball flight. It was also found that in general the LVMr is influenced by the type of information used. Thus, when taking into account the trials during which there was spatial anticipation, reflected in LVMr of the whole body, the times decreased (152 vs. 136 ms). On the other hand, there were occasions (13%) where both international and national players responded late, thus receiving aces (208 vs. 195 ms). It is quite possible that in these cases the players have had trouble to pick-up information, responding out of temporary margins of action, which affected their performance. The same could have occurred when both groups of players corrected upper limb movement after impact (17% vs. 10%), which increased the time to respond and to redirect the return towards the right side (208 vs. 205 ms). Moreover, international players scored lower movement times than the national players (509 vs. 531 ms), which was reflected in a shorter total response time (683 vs. 703 ms). Finally, as far as the performance of return is concerned, international players scored above the national players values (1.3 vs. 0.9).