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- Estudos em desenvolvimento motor da criança XVPublication . Correia, Vanda; Pereira, Elsa; Carvalho, João; Minhalma, Ricardo J. P.O que é uma criança? Esta é uma questão simples e clara, fundamental, mas certamente de difícil resposta. Na história da humanidade, a criança é uma entidade que apenas ganha um contorno e identidade em tempos recentes. Entre um ser humano imperfeito e uma pureza divina; entre uma página em branco e uma reencarnação; entre uma vontade própria e uma plasticidade extrema. A ideia de criança, tal como a conhecemos hoje, é não só recente como extremamente diversificada, em função de contextos sociais, culturais e até políticos. Quando a população mundial cresceu como nunca tinha acontecido e quando a mortalidade infantil mostrou sinais de cedência face ao controlo das doenças infeciosas e aos cuidados perinatais, a ideia de criança ganhou, talvez, uma identidade própria. A nova pirâmide etária, que apresenta pela primeira vez um grupo demográfico jovem e populoso, traz novos problemas para os decisores públicos. O que fazer com tanta gente nova? como orientar o seu desenvolvimento? Como gerir o seu bem-estar e o seu tempo? Tantas e tão complexas questões colidem com um imenso desconhecimento sobre o objeto das perguntas. Sem surpresa, o mundo vai precisar de saber o que é isso de ser criança.
- Evaluation of upper limb joint contribution to racket head speed in elite tennis players using IMU sensors: comparison between the cross-court and inside-out attacking Forehand DrivePublication . Pedro, Bruno; João, Filipa; Lara, Jerusa P. R.; Cabral, Silvia; Carvalho, João; Veloso, António P.This study aimed to quantify and compare the upper limb angular kinematics and its contributions to the racket head speed between the cross-court (CC) and inside-out (IO) attacking tennis forehand of elite tennis players in a competitive environment. A new approach was used to study the forehand drive with mini-inertial sensors of motion capture to record the kinematic data. Six strokes in each direction per participant (72 shots in total) were chosen for analysis. Upper limb kinematics were calculated in the Visual 3D platform (Visual 3D Professional V5.01.21, C-motion, Germantown, MD, USA). The method used to calculate the upper limb’s contributions was performed with MATLAB software and used the segment’s (upper arm, forearm and hand) angular velocities and their respective displacement vectors obtained through the inertial sensors. Upper limb kinematics demonstrated a higher shoulder rotation in the IO direction with significant differences at the end of the backswing, which could be a key factor in distinguishing the two directions of the shot. Results also demonstrated that the horizontal flexion of the upper arm (around the shoulder joint) was primarily responsible for the racket velocity in the anteroposterior direction (48.1% CC and 45.2% IO), followed by the extension of the forearm (around the elbow joint) (17.3% CC and 20.9% IO) and the internal rotation of the upper arm (around the shoulder joint) (15.6% CC and 14.2% IO). No significant differences were shown in the contributions of upper limbs to the racket head velocity between the two directions of the shot. Tennis coaches and players should develop a specific training programme to perform higher angular velocities in these specific joint rotations.
- El entrenamiento de la toma de decisiones en el tenis: ¿qué fundamentos científicos se pueden aplicar en los programas de entrenamiento?Publication . Carvalho, João; Araujo, Duarte; Garcia Gonzalez, Luis; Iglesias, DamianThis paper is a review of the research literature on decision-making in sports, especially tennis. It discusses the theoretical constructs underpinning the different approaches and the most frequently used methodological procedures and their limitations and shows the need for this practice to be based on scientific evidence and the performance of high-level tennis players. Based on the theoretical rationale of ecological dynamics, we put forward a new proposal for decisionmaking training based on the manipulation of constraints. To wind up, the paper proposes several methodological suggestions to be taken into account in future research in the area of decision-making training in tennis.
- Perceived self-efficacy by Under-10 tennis players when scaling the equipment and play areaPublication . Gimenez-Egido, Jose Maria; Carvalho, João; Araújo, Duarte; Ortega-Toro, EnriqueThe modification of child-sports aims to develop an optimal learning environment that facilitates the emergence of desirable psychological outcomes (e.g., self-efficacy). The aim of the study was to assess the effect of reducing net height and court size on self-efficacy and shot-efficacy of U-10 tennis players in a real-game context. Twenty U-10 tennis players (M = 9.46, SD = 0.66 years of age; M = 3.65, SD = 1.53 years of tennis experience) played two round-robin tournaments one week apart in the same order and schedule. The first tournament was played under the International Tennis Federation's Tennis 10s regulation at green stage (GT). Afterwards, the modified tournament (MT) was played with the same regulation GT, however, net height (0.91 m-0.80 m) and court size (23.77 m x 8.23 m-18.00 m x 8.23 m) were reduced. Results accomplished using Bayesian and Frequentist inferences showed an increase in players' self-efficacy when serving in MT than GT (BF10 = 4.796; delta =-0.576; and p = .011). This is increase may be due to a reduction in their serving faults in MT (BF10 = 6.169; delta =-0.591; and p = .010). Therefore, reducing net height and court size enhances the serve performance and self-efficacy and thus promotes positive tennis experiences.
- Panorámica de las teorías y métodos de investigación en torno a la toma de decisiones en el tenisPublication . Garcia-Gonzalez, Luis; Araujo, Duarte; Carvalho, João; Iglesias, DamianIn this theoretical and methodological review of decision making in tennis, we describe some of the explanatory theories of the decisional process by using two approaches: cognitive psychology and ecological psychology. Within the former approach, based on models of information processing, we focus on the importance of visual and perceptual behaviour as mediators of anticipation and decision-making skills in tennis, as well as related concepts such as attention and visual acuity. Subsequently, we explain other cognitive theories based on mental representations and the development of different types of knowledge and memory as a central and decisive component in decision making. The latter approach describes decision making on the basis of ecological psychology, using a decision making approach to the ecological dynamics, heightening the importance of the setting and constraints and understanding tennis as a non-linear, dynamic and self-organized system. We discuss various methodological approaches for evaluating decisions in tennis, regardless of the framework that sustains them. We present different ways of evaluating the decision-making process by analysing verbal protocols and questionnaires, observational analysis, kinematic variables analysis and perceptive analysis. Finally, we conclude by presenting the need to overcome several limitations and study decision making in a holistic manner in which decision making is linked directly to game action.
- Perturbations created from the baseline in tennis: a test of barker’s behaviour setting theoryPublication . Carvalho, Adriano; Carvalho, João; Araújo, DuarteThe purpose of this study was to characterise perturbations created from the baseline in men's tennis following Barker's ecological psychology approach. In selected rallies of expert level tennis matches we identified the shot responsible for this perturbation and characterised it using a sequential approach based on the positioning of the players in the court, the technical actions used by both players, and the displacements that each player forced on the opponent. Results reveal specific patterns of player behaviour and types of displacement in response to the opponent. Moreover, we found significant variability of the technical actions and action zones expressed during the perturbation processes. These results suggest that perturbation behaviours are constrained by the 'behaviour setting', which allows individuality during the search for effective solutions to achieve a specific goal. This test of Barker's behaviour setting theory in sport offers a principled guidance for coaches embed psychology into task design for practice sessions.