scholarly journals An 8-Stage Model for Evaluating the Tennis Serve

2011 ◽  
Vol 3 (6) ◽  
pp. 504-513 ◽  
Author(s):  
Mark Kovacs ◽  
Todd Ellenbecker

Background: The tennis serve is a complex stroke characterized by a series of segmental rotations involving the entire kinetic chain. Many overhead athletes use a basic 6-stage throwing model; however, the tennis serve does provide some differences. Evidence Acquisition: To support the present 8-stage descriptive model, data were gathered from PubMed and SPORTDiscus databases using keywords tennis and serve for publications between 1980 and 2010. Results: An 8-stage model of analysis for the tennis serve that includes 3 distinct phases—preparation, acceleration, and follow-through—provides a more tennis-specific analysis than that previously presented in the clinical tennis literature. When a serve is evaluated, the total body perspective is just as important as the individual segments alone. Conclusion: The 8-stage model provides a more in-depth analysis that should be utilized in all tennis players to help better understand areas of weakness, potential areas of injury, as well as components that can be improved for greater performance.

2018 ◽  
Vol 72 (5) ◽  
pp. 1131-1140
Author(s):  
Hirofumi Ida ◽  
Kazunobu Fukuhara ◽  
Motonobu Ishii ◽  
Tetsuri Inoue

This study was aimed at determining how the visual information of an end-effector (racket) and the intermediate extremity (arm) of a tennis server contribute to the receiver’s anticipatory judgement of ball direction. In all, 15 experienced tennis players and 15 novice counterparts viewed a spatially occluded computer graphics animation of a tennis serve (no-occlusion, racket-occlusion, and body-occlusion) and made anticipatory judgements of ball direction on a visual analogue scale (VAS). The patterns of the serve motions were generated by a simulation technique that computationally perturbs the rotation speed of the selected racket-arm joint (forearm pronation and elbow extension) on a captured serve motion. The results suggested that the anticipatory judgements were monotonically attuned with the perturbation rate of the forearm pronation speed excepting under the conditions of the racket-occlusion model. Although such attunements were not observed in the elbow perturbation conditions, the results of correlation analysis indicated that the residual information in the spatially occluded models had a similar effect to the no-occlusion model within the individual experienced participants. The findings support the notion that end-effector (racket) provides deterministic cues for anticipation, as well as imply that players are able to benefit from the relative motion of an intermediate extremity (elbow extension).


2021 ◽  
Vol 12 ◽  
Author(s):  
Jernej Rosker ◽  
Ziva Majcen Rosker

Analyzing visual search strategies in tennis is primarily focused on studying relationships between visual behavior and tennis performance. However, diverse movement characteristics among different servers suggest the importance of adjusting the visual search strategies of an individual while playing against different opponents. The aim of this study was to analyze whether visual search strategies can be attributed to the individual server and the returning player during the tennis serve return or return performance. Seventeen tennis players were enrolled in this study (five international players and 12 national players) producing a sample of 1,020 returns measured with mobile eye trackers. The random forest machine learning model was used to analyze the ability to classify the returning player [area under the curve (AUC): 0.953], individual server (AUC: 0.686), and return performance category (AUC: 0.667) based on the location and duration of the focal vision fixation. In international tennis players, the higher predictability of the server was observed as compared with national level players (AUC: 0.901 and 0.834, respectively). More experienced tennis players presented with a higher ability to adjust their visual search strategies to different servers. International players also demonstrated anticipatory visual behavior during the tossing hand movement and superior information pickup during the final phases of the stroke of a server.


Retos ◽  
2021 ◽  
Vol 42 ◽  
pp. 365-374
Author(s):  
Sagrario Lobato Huerta ◽  
Juan Víctor Moneda Rovira ◽  
Yaneth Martínez Tovilla ◽  
José Hugo Eloy Meléndez Aguilar

  El lenguaje según Noam Chomsky, es una capacidad innata que puede emplearse para comunicar la ciencia. Analizar el término obesidad como concepto científico, permitirá su correcto abordaje epistemológico para contribuir con la investigación científica multidisciplinaria que busca reducir esta pandemia. La obesidad es una acumulación excesiva de grasa corporal, por encima de las necesidades fisiológicas y capacidad de adaptación, que puede conducir a efectos adversos para la salud, como una discapacidad. Se considera un estado en el que el tejido adiposo representa más del 20% del peso corporal total en hombres y el 25% en mujeres. Un IMC de 30 kg/m2 o más se cataloga como obesidad. Desde una perspectiva genética, la obesidad es clasificada en tres subdivisiones de acuerdo con el trastorno y número de genes involucrados: monogénica, sindrómica y poligénica. Para las ciencias sociales, involucra un problema sociocultural injertado en una predisposición a nivel individual. Desde la perspectiva evolutiva, el cuerpo humano no está desarrollado para la exposición constante a un ambiente rico en calorías y sedentario. Comprender las perspectivas teóricas actuales que conceptualizan a la obesidad, estipulada como patología en sí misma, como factor de riesgo para las demás enfermedades no transmisibles y como etiología indirecta de discapacidad, permitirá que la investigación científica pueda desarrollarse con panoramas más amplios, a través de su diseño con variables, categorías y teorías mixtas, que permitan formular hipótesis y explicaciones con un enfoque multidisciplinario, en concordancia con la etiología multifactorial de la obesidad.  Abstract. Language according to Noam Chomsky, is an innate ability that can be used to communicate science. Analyzing the term obesity as a scientific concept will allow its correct epistemological approach to contribute to multidisciplinary scientific research that seeks to reduce this pandemic. Obesity is an excessive accumulation of body fat, in excess of physiological needs and adaptability, which can lead to adverse health effects, such as disability. It is considered a state in which adipose tissue represents more than 20% of total body weight in men and 25% in women. A BMI of 30 kg / m2 or more is classified as obesity. From a genetic perspective, obesity is classified into three subdivisions according to the disorder and number of genes involved: monogenic, syndromic and polygenic. For the social sciences, it involves a sociocultural problem grafted onto a predisposition at the individual level. From an evolutionary perspective, the human body is not developed for constant exposure to a calorie-rich and sedentary environment. Understanding the current theoretical perspectives that conceptualize obesity, stipulated as a pathology in itself, as a risk factor for other non-communicable diseases and as an indirect etiology of disability, will allow scientific research to be developed with broader perspectives, through its design with mixed variables, categories and theories, which allow the formulation of hypotheses and explanations with a multidisciplinary approach, in accordance with the multifactorial etiology of obesity.


2017 ◽  
Vol 16 (1) ◽  
pp. 49-53 ◽  
Author(s):  
Joseph Zappala ◽  
Carolina Orrego ◽  
Emily Boe ◽  
Heather Fechner ◽  
Derek Salminen ◽  
...  

2019 ◽  
Vol 9 (2) ◽  
pp. 75-88
Author(s):  
Luka Šlosar ◽  
Matej Plevnik ◽  
Uroš Marušič

Aim: The purpose of this pilot study was to quantify the effect of a continued active video games (AVG) playing on the tennis forehand and backhand technique development. Methods: Altogether 24 tennis players (7 – 9 year olds) were randomly divided in two different groups, both involved in a 12-week tennis training program (twice a week for an hour). The participants in the experimental group received an additional twice a week (20-minute) AVG Virtua Tennis 4 game intervention at the end of each regular tennis training hour, while the participants in the control group received no additional intervention. Pre- and post-AVG intervention, the Tennis Rating Score for Children scale (TRSC) was applied to detect tennis training-related changes that occur in each specific stroke. Results: Our results at the post-test show that participants in the experimental group did not significantly improved in one element (TRSC12; p = 0,317) in the forehand stroke and two (TRSC10; p = 0,157 and TRSC12 p = 0,157) in the backhand. The control group significantly improved in all the fifteen evaluated elements in both the forehand and backhand stroke. The experimental group had a higher effect size in all the kinetic chain section in both the forehand and backhand stroke compared to the control. The same happens for the TRSC7 (point of contact – height). Conclusion: Prolonged AVG playing seems to improve visual attentions skills (perception of a moving object) in young tennis players, giving them the opportunity to be able to prepare themselves for the oncoming ball sooner as compared to their control counterparts. From the other perspective, AVG were shown to negatively affect correct players positioning, especially at the beginning and at the end of a stroke. Keywords: exergames, tennis technique, visual attention skills


2018 ◽  
Vol 11 (4) ◽  
pp. 2485-2500 ◽  
Author(s):  
Anne Garnier ◽  
Thierry Trémas ◽  
Jacques Pelon ◽  
Kam-Pui Lee ◽  
Delphine Nobileau ◽  
...  

Abstract. Version 2 of the Level 1b calibrated radiances of the Imaging Infrared Radiometer (IIR) on board the Cloud-Aerosol Lidar and Infrared Satellite Observation (CALIPSO) satellite has been released recently. This new version incorporates corrections of small but systematic seasonal calibration biases previously revealed in Version 1 data products mostly north of 30∘ N. These biases – of different amplitudes in the three IIR channels 8.65 µm (IIR1), 10.6 µm (IIR2), and 12.05 µm (IIR3) – were made apparent by a striping effect in images of IIR inter-channel brightness temperature differences (BTDs) and through seasonal warm biases of nighttime IIR brightness temperatures in the 30–60∘ N latitude range. The latter were highlighted through observed and simulated comparisons with similar channels of the Moderate Resolution Imaging Spectroradiometer (MODIS) on board the Aqua spacecraft. To characterize the calibration biases affecting Version 1 data, a semi-empirical approach is developed, which is based on the in-depth analysis of the IIR internal calibration procedure in conjunction with observations such as statistical comparisons with similar MODIS/Aqua channels. Two types of calibration biases are revealed: an equalization bias affecting part of the individual IIR images and a global bias affecting the radiometric level of each image. These biases are observed only when the temperature of the instrument increases, and they are found to be functions of elapsed time since night-to-day transition, regardless of the season. Correction coefficients of Version 1 radiances could thus be defined and implemented in the Version 2 code. As a result, the striping effect seen in Version 1 is significantly attenuated in Version 2. Systematic discrepancies between nighttime and daytime IIR–MODIS BTDs in the 30–60∘ N latitude range in summer are reduced from 0.2 K in Version 1 to 0.1 K in Version 2 for IIR1–MODIS29. For IIR2–MODIS31 and IIR3–MODIS32, they are reduced from 0.4 K to close to zero, except for IIR3–MODIS32 in June, where the night-minus-day difference is around −0.1 K.


Author(s):  
Robert C Manske ◽  
Mark Stovak ◽  
Peter Loo ◽  
Michael Breunig ◽  
Todd Ellenbecker ◽  
...  

Interval tennis rehabilitation programs (ITRPs) are advocated during later stages of shoulder and elbow rehabilitation. ITRPs utilize gradual increases in hitting or serving effort, based on perceived effort. Over-estimation of effort may increase stress. This investigation purpose was to determine actual tennis serve velocity when asked to hit serves at perceived effort of 50%, 75%. Thirty-nine healthy college tennis players performed a warm-up of groundstrokes and serves. Five maximal effort serves (100% velocity) functioned as the 100% maximal effort serve. Then, five serves were hit at each of two randomly determined velocities. The average of five trials for maximum effort (100% velocity) was calculated. Based on this number, 75% and 50% of maximum velocity was determined. Using one-sample t-tests, the subjects’ perceived efforts were compared against computed percentages. Differences were found between perceived effort and calculated percent. Overall, actual velocity served was greater than percieved. Because velocity at 100% effort was significantly different for males and females, a separate analyses was done by gender. Both males’ and females’ perceived velocities were significantly greater (p < .05) than the athletes’ computed velocities at 75% and 50%, respectively. Perceived serve effort does not equate to actual ball velocity. A need exists to use other measures to determine effort or intensity during ITRPs. Serving at higher velocity levels early after musculoskeletal shoulder or elbow injury may increase the risk of re-injury or lack of progression. This study provides clinicians with guidance for the progression of tennis players during an interval program.


Energies ◽  
2020 ◽  
Vol 13 (19) ◽  
pp. 5059
Author(s):  
Sebastian Łapczyński ◽  
Michał Szulborski ◽  
Karol Gołota ◽  
Łukasz Kolimas ◽  
Łukasz Kozarek

The purpose of this work is to discuss the tulip contact behavior during mechanical and electrical simulations in a Finite Element Method (FEM) environment using ANSYS and COMSOL software. During the simulations, the full contact movement was analyzed. During the contact movement, the individual behavior of the contact components was taken into consideration. The motion simulation was carried out at different velocities and forces acting on the contact. The obtained results were compared to each other and discussed. Relatively, the angles of the contact surfaces to each other were also changed, which meant that we could conduct a more in-depth analysis. The other approach of simulation research was a field analysis of physical phenomena occurring in the tulip contact. This analysis was performed in COMSOL Multiphysics. Parametric analysis allowed an observation of the electric field in the tulip contact at different contact distances with respect to each other. This work is important in terms of the cost effectiveness for design procedures concerning tulip contacts and fault avoidance, which both result from mechanical and electrical conditions throughout contact exploitation and optimization of the working conditions for the tulip contact.


2014 ◽  
Vol 45 (1) ◽  
pp. 15 ◽  
Author(s):  
Lucia P. Caliandro ◽  
Rosa V. Loisi ◽  
Pasquale Dal Sasso

A precise category of Apulian farmsteads, known as <em>masserie</em>, is a significant example of rural buildings featuring relevant architectural and landscape characteristics. Their territorial distribution is diversified and often depend on the close relationship between the building and its adjacent agricultural lot. Moreover, owing to their specific role in overseeing the territory and asserting land tenure rights, Apulian <em>masserie</em> distribution may have genetic origins influenced by other elements, too. The aim of this work is to investigate the existing relationships between <em>masserie</em> and historic roads crossing the Apulia region (Roman roads and sheep’s paths called <em>tratturi</em>), considering both their mutual distance and the individual rural buildings importance. Overlay mapping procedures allow to quantify the amount of <em>masserie</em> falling within the catchment areas of the aforementioned historical roads, while historical and territorial in-depth analysis helped to identify those elements characterising the most interesting <em>masserie</em> from cultural and architectural points of view. The research provided interesting qualitative and quantitative information on the existing relations between these assets, leading to further considerations on the possibility to enhance them through the promotion of their integrated recovery.


1995 ◽  
Vol 11 (4) ◽  
pp. 433-442 ◽  
Author(s):  
Bruce C. Elliott ◽  
Robert N. Marshall ◽  
Guillermo J. Noffal

In the high-velocity tennis serve, the contributions that the upper limb segments' anatomical rotations make to racket head speed at impact depend on both their angular velocity and the instantaneous position of the racket with respect to the segments' axes of rotation. Eleven high-performance tennis players were filmed at a nominal rate of 200 Hz by three Photosonics cameras while hitting a high-velocity serve. The three-dimensional (3-D) displacement histories of 11 selected landmarks were then calculated using the direct linear transformation approach, and 3-D individual segment rotations for the upper limb were calculated using vector equations (Sprigings, Marshall, Elliott, & Jennings, 1994). The major contributors to the mean linear velocity of the center of the racket head of 31.0 m · s-1 at impact were internal rotation of the upper arm (54.2%), flexion of the hand (31.0%), horizontal flexion and abduction of the upper arm (12.9%), and racket shoulder linear velocity (9.7%). Forearm extension at the elbow joint played a negative role (-14.4%) and reduced the forward velocity of the center of the racket at impact.


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