Increase in the effectiveness of technical displacement in tennis players through specific coordination exercises
Aumento de la eficacia de la técnica de desplazamientos en jugadores de tenis a través de ejercicios específicos de coordinación Ph.D. Santiago Calero Morales Departamento de Ciencias Humanas y Sociales de la Universidad de las Fuerzas Armadas ESPE. (Ecuador)
[email protected]
Dr. Enrique Chávez Cevallos
[email protected]
Bach. Esteban Casares Benítez
[email protected]
Abstract
This research aims to implement a set of specific coordination exercises to increase the effectiveness of technical movements in tennis players of the Tennis Association of Pichincha, Ecuador. Eight players from 15 to 18 years old are undergone to a study, observationally assessing 7 parameters (Split Step, Side Scrolling, Diagonal Scrolling, Forward Movement, Backward Movement, recovery of the Initial Position and their effectiveness) before and after the proposal are implemented. For the evaluation of the parameters, there were selected 7 specialists with a high level of reliability in observational records. The study demonstrates the existence of improvements in the management process of sports training to increase the effectiveness in the technical movements depending on the coordination of the sample under study, since the evidence of Wilcoxon signedrank test determined a significant difference in effectiveness between the pretest and posttest, techniques for Forehand Hit (Right: 0.028 and 0.031 respectively) and Hit backhand (Hitting Backhand: 0.028 and 0.31 respectively). Keywords: Tennis. Mobility. Coordination. Effectiveness. Forehand hit. Backhand hit. Resumen La investigación tiene como objetivo implementar un conjunto de ejercicios de coordinación específicos para aumentar la eficacia de los movimientos técnicos en los jugadores de tenis de la Asociación de Tenis de Pichincha, Ecuador. Ocho jugadores de 15 a 18 años fueron sometidos a un estudio en el que se evaluó mediante la observación siete parámetros (Paso Split, Desplazamiento horizontal, Desplazamiento Diagonal, el movimiento hacia adelante, hacia atrás, la recuperación de la posición inicial y la eficacia de estos) antes y después de implementada la propuesta. Para la evaluación de los parámetros fueron seleccionados siete especialistas con un alto nivel de fiabilidad en los registros de observación. El estudio demuestra la mejora de la gestión del proceso de entrenamiento deportivo para aumentar la eficiencia en los movimientos técnicos, en función de la coordinación de la muestra estudiada, ya que la prueba con rangos de signos de Wilcoxon determina una diferencia significativa en la eficacia entre el pretest y el posttest, en las técnicas del golpe de derecha (derecha: 0,028 y 0,031, respectivamente) y revés (golpe de revés: 0,028 y 0,31, respectivamente). Palabras clave: Tenis. Movilidad. Coordinación. Eficacia. Golpe directo. Golpe de revés. Reception: 03/29/2016 Acceptance: 10/07/2016 1st Review: 06/22/2016 2nd Review: 06/07/2016 EFDeportes.com, Revista Digital. Buenos Aires Año 21 Nº 218 Julio de 2016. http://www.efdeportes.com/
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INTRODUCTION The process of directing the sport training of the tennist player include multiple factors (Ortiz, 2004; Vila, 2006; Hurtado, 2011; Reilly; Hughes & Lees, 2013; Coutinho, 2014-2015) which are decisive to reach a high performance. These factors take part of the process since the initial training of players at early ages until the multilateral development through which they pass during their active life. The coordination of the tennis player is highly important during the training (Grosser & Schonborn, 2002; Bourqouin, 2003; Weineck, 2005; Knudson, 2006; Ivancevic & et al, 2010); for that reason several exercises are designed for the preparation of the tennist player according to previously stated goals, as it is set in Freo (1998). In scientific literature stand out papers related to the significance of the coordination capacity during the process of learning the tennist player’s skills (Meierhofer, 1989; Torres and Carrasco, 1998; Zetou, Vernadakis, Tsetseli, Kampas,
&
Michalopoulou,
2012),
since
this
ability,
according
to
the
aforementioned authors, is one of the most important aspects of the specific sport training, taking into account that the coordination skills are the most significant elements in order to identify if a program improves the teaching-learning process of tennis. Other papers tackle some tests to evaluate skills related to the serve (Mantis, Zachopoulou, & Mavridis, 1998), which include mobility and coordination, while Abernethy (1988) studies the effects of age and the experiences in the development of perception skills in racket sports; based on this paper , Fatouros, Aggelousis, Gourgoulis & Taxildaris (2003) valuate the effect of age and gender in the coordination abilities during childhood. The above is a deduction that the work of the coordination ability is vital to systematically increase the sport performance of the tennist player since the early ages until the utmost performance. The estimation of the effectiveness in sports is vital to stablish indicators that evaluate the sport performance, and for that several statistic formulas are applied. Some of them can be checked at FIVB (2003), Iriarte, (2004), Campo (2008),
Calero (2009-2010), Menayo (2010), Baiget, Iglesias, Vallejo & Rodríguez (2011) & Losada, Casa & Árda, (2015), among others. In addition, there are scales stablished to quantitatively and qualitatively determine the performace according to the function-objective to be determined (Solanellas, 1999; Lacambra, Gimeno & Colas, 2012; Calero, Suárez & Fernández, 2012 a,b; Flores, Calero, Arancibia & García, 2014 a,b), a useful aspect to compare and indicate performance levels. Specifically, there are several studies that apply hitting performance tests (Vergauwen et al., 1998; Vergauwen et al., 2004; Moya et al., 2010), for that reason this might be a good method to stablish indicators that demonstrate the improvement or not of a determined process. On the other hand, the definition of displacement tackled in this paper is closely related to the concept of sport technique, which is considered, from the biomechanical point of view, as a feature of the sport disciplines which are highly standarized in practical terms through a rational and ideal technical model, and more in those that are not directly opposed to the rival (Nitsch, Neumaier, Marées & Mester, 2002; Izquierdo, 2008; McGarry, O'Donoghue & Sampaio, 2013; León, Calero & Chávez, 2014), but apart from being based on the laws of classic Physics, are related to the theory and methodology of the sport training through the definition of execution parameters and performance standards, which allow an immovable link bewteen technique and tactic, hence the tennist player’s displacement (opposition sport) is inextricably linked to the technical movement and its relation with the tactic (Izquierdo, 2008). Because of that, the results of both components of the training will determine the existence or not of an appropriate final performance, specially in sports of cooperation-opposition (Calero, 2009), which will not only depend on that link, but on the relation and strengthening of other sport abilities (Martin, 2011; McGarry, O'Donoghue & Sampaio, 2013; Calero y González, 2015).
As it is stated by Vasconcelos (2000), an athlete with a deficient technique will see their load ability limited as long as the fatigue of the coordinative defficiency is quite precocius. In a way or another, the physical skills of an athlete are interralated and all of them, ones more than others, have a general influence in the efficient performance of the athlete, which is expressed through the sport ouput. The increase of the mobility in the tennis player is vital to reach high performances, for that reason it is our strategic goal to increase the displacement levels of the player of the Tennis Association of Pichincha through the design of special coordination exercises. MATERIAL AND METHODS Eight athletes bewteen 15 and 18 years old will be studied. They are part of the Tennis Association of Pichincha, Republic of Ecuador. There is also a selection of 7 specialists in statistics applied to tennis to quantitatively and qualitatively evaluate several observational indicators related to coordination (Split Step, Side Scrolling, Diagonal Scrolling, Forward Movement, Backward Movement, Recovery of the Initial Position and Effectiveness). These specialists have been undergone to a reliability qualitative test, using the modified Anguera (1987) method. Each scorer-evaluator will record the data in groups of 5 per parameter in the corresponding order, evaluating the amount of actions and classifying them into “Acceptable” and “Unacceptable”, during the game ( three sets). It is used Microsoft Excel 2013 to tabulate the data and determine basic statistics, mainly descriptive; on the other hand it will be used the SPSS v21 to determine the Wilcoxon signed-ranks test, under a signification level of 0,05. The exercises designed to increase the mobility based on the coordination were applied during six months, and they are described as follows: Table 1: Exercise 1 Name of the Exercise: The ladder Objective: Develop coordination Description/execution: a column of 4-8 athletes and before them a rope ladder on the floor. The coach will make a signal to the athletes who will start doing the exercise one
after the other. Series: 3 per exercise Repetitions: 12-15 seconds according to the development of the player Pause: 45 seconds Intensity: average according to the development of the player Variant: multiple Ex.: ZIG ZAG, in and out, running over, etc. Method: discontinuous repetitions Methodological indications: The athlete will position before the ladder with the legs semi-bent and open to the shoulder width and a slight elevation of the heels helping the weight of the body moves forward, where the center of gravity should be near the ground.
Table 2: Exercise 2 Name of the exercise: Coordination Objective: Develop coordination exercises with specific tennis exercises Description/execution: This exercise was designed using the circuit method, each player will position in a station where there will be a coordinated specific tennis movement, always racket in hand. Series: go through all stations Repetitions: 2 to 3 Pause: 10 seconds of work and 10 of rest, and one minute after finishing the circuit. Intensity: average according to the development of the player Variant: multiple Ex.: right stroke between cones, combination of volley and overhead smash, motion volleys using cones, etc. Method: discontinuous repetitions Methodological indications: The players will execute strokes and movements with quality.
Table 3: Exercise 3 Name of the exercise: Working with Objective: develop power and coordination hurdles Description/execution: a series of hurdles set as quadrants making up to three and put at the level of the knees, the player will execute coordinated jumps until completing the three quadrants. Series: 3 per exercise Repetitions: 2 to 3 with pause until calmed Intensity: high according to the development of the player Variant multiple Ex. After finishing the three quadrants quick, add another or lower the height of one of the quadrants, etc.. Method: discontinuous repetitions Methodological indications: The player will have the legs semi-bent and always in motion and open to the shoulder width, jumping over the cones where he will fall sometimes with both feet on the ground, and some other times in one foot.
Table 4: Exercise 4 Name of the exercise: Playing with Objective: Improve mobility focused on coordination coordination Description/execution:1 Repetitions: According to the need and the level of motivation of the athletes. Intensity: average according to the development of the player Variant: multiple Ex.: ZIG ZAG , in and out, running over, etc. Method: discontinuous repetitions Methodological indications: The player, racket in hand will move as fast as possible and coordinate towards the ball, wil keep the head straight and the trunk will not bend more than normal. Means: It will be used auxiliary tools such as: cones, rope ladder specifically for tennis, hurdles, whistles, chronometers.
As part of the design were included other plyometric means to specifically work the Power based on Coordination. Table 5. Scales of quantitative and qualitative values for the evaluation of the Results. Effectiveness percentage 90 -100 % 75,5 -89,9 % 65,5 -75,4 % 50 -65,4
Evaluation Excellent (E) Very Good (MB) Good (B) Average (R)
The previous values were created to stablish evaluation indicators as those created to stablish evaluable parameters that pursuit other goals but have points in common, as they were detailed by Calero, Suárez & Fernández (2012 a,b) and Flores, Calero, Arancibia & García (2014 a,b). ANALYSIS OF THE RESULTS AND DISCUSSION Table 6: Initial observations of the mobility of the players undergone to the study. Effectiveness by parameters.
1
Omitted by request of the coaches envolved in the process
Parameters No 1
Backhand
Right Acceptable Unacceptable Total
Split step
%
9
21
30
30,00
16
10
26
61,54
12
7
19
63,16
5
6
11
45,45
16
9
25
64,00
20
18
38
52,63
Side Scrolling
2 3
Diagonal Scrolling
4
Forward Movement
5
Backward Movement
6
Initial Position recovery
Total Effectiveness percent Evaluation
Total
Acceptable Unaceptable Total
%
M
6
15
21 28,57 29,29
10
8
18 55,56 58,55
14
6
20 70,00 66,58
5
6
11 45,45 45,45
17
6
23 73,91 68,96
16
7
23 69,57 61,10
52,80%
57,18%
R
R
54,59%
The Effectiveness is processed through the calculation between the acceptable and the total (Example: Split step = 9/30 = 30,00%). This statistic formula is usually used in tennis as in other sports such as volleyball; as it was demonstrated in FIVB (2003), Iriarte, (2004), Campo (2008), Calero (2009-2010), Menayo (2010), Baiget, Iglesias, Vallejo & Rodríguez (2011) and Losada, Casa & Árdá, (2015), previously mentioned. The aforementioned delimits a level of effectiveness of 30,00% in the Split step; an effectiveness of 61,54% in the side scrolling; an effectiveness of 63,16% in the diagonal scrolling; and effectiveness of 45,45 in the Forward Movement; an effectiveness of Backward Movement of 64,00% and an effectiveness in the Initial Position Recovery of 52,63%. The Total Effectiveness in the Forehand Hit was determined at 52,80 %.
R
On the other hand, the effectiveness study in the indicators for the movement technique of Backhand Hit determined an effectiveness of 28,57% for the split step; of 55,56% for the side scrolling; 70,00 % of diagonal scrolling; 45,45% for the Backwards scrolling of 73,91% and for the Initial Position Recovery of 69,57%. While the total effectiveness percentage is of 54,59%, higher than the total effectiveness of the technique with the Forehand Hit (52,80%). Based on Table 5 (Scale of values), the percentage of the total effectiveness reached by the players undergone to the study in the initial phase of the investigation determined an Average (R) qualitative indicator for the Backhand Hit technique (57,18%) as for the Forehand Hit technique, since the effectiveness data are in the range 50-65,4%. After determining the percents of effectiveness of the observational indicators previously described, it was applied the strategy with the new coordination exercises in order to evaluate the existence or not of improvements in the direction process of the sport training of the tennist player studied. Table 7: Final observations of the mobility in the players undergone to study after the application of the proposal of coordination exercises for a six-month period. Effectiveness by parameters. Parameters No 1
Backhand
Forehand acceptable unacceptable Total
Split step Side Scrolling
2 3
Diagonal Scrolling
4
Forward Movement
%
Total
acceptable unacceptable Total
%
M
15
14
29 51,72
11
9
20 55,00 53,36
20
11
31 64,52
16
7
23 69,57 67,04
15
5
20 75,00
13
4
17 76,47 75,74
9
4
13 69,23
10
4
14 71,43 70,33
5
Backward Movement
17
6
23 73,91
18
4
22 81,82 77,87
6
Initial Position recovery
21
9
30 70,00
17
6
23 73,91 71,96
Total Effectiveness percent Evaluation
67,40 B
71,37 69,38 B
B
As it has been stated (by applying the proposal for a six-month training period), the results reached are described in Table 7, where the effectiveness reached in the Split Step indicator or parameter for the Forehand Hit technique was of 51,72 %, the Side Scrolling effectiveness of 64,52%, Diagonal Scrolling of 75,00%, Forward Scrolling 69,23%, the Backwards Scrolling of 73,91% and the Initial Recovery Position 70,00% of effectiveness. The Right Hit technique had a total effectiveness of 67,40% obtaining a qualitative evaluation according to the scale of values of Table 5 (Rank: 65,5 -75,4 %) of Goog (B). On the other hand, the data obtained in the Backhand Hit technique obtained the following results of the effectiveness reached in Split Step parameter of 55,00 %, the effectiveness of the Side Scrolling of 69,57%, the Diagonal Scrolling 76,47%, the Forward Scrolling of 70,30%, the Backward Scrolling of 81,82% and the Initial Position Recovery of 73,91%. The Backhand technique obtained a total effectiveness percentage of 71,37%, obtaining a qualitative evaluation according ot the scale of values of Table 5 (Rank: 65,5 -75,4 %) Good (B). Both the data obtained in table 6 and 7 showed that the Backhand Hit technique, has presented a higher sport performance in terms of coordination than the Forehand Hit technique. Table 8: Comparison of the Forehand Hit technique effectiveness befote and alter the application of the proposal. Wilcoxon signed-ranks test.
Parameter
Effectiveness Before (Pretest) Effectiveness After (Postest) 30,00 51,72 61,54 64,52 Side Scrolling 63,16 75,00 Diagonal Scrolling Forward Movement 45,45 69,23 Backward Movement 64,00 73,91 Initial Position recovery 52,63 70,00 Split step
Ranks
E.Right Postest E.Right Pretest
Negative ranks Positive ranks Draws Total
N
Average Rank Rank Sum ,00 ,00 3,50 21,00
0(a) 6(b) 0(c) 6 a E. Right Postest < E.Right Pretest b E. Right Postest > E. Right Pretest c E. Right Postest t = E. Right Pretest
Contrast Statistics (b)
E. Right Postest – E. Right Postest Z -2,201(a) Sig. asympt(bilateral) ,028 a Based on the negative ranks. b Wilcoxon signed-ranks test. Frequencies
E. Right Postest E. Right Postest
Negative Differences(a) Positive Differences(b) Draws(c) Total
a E. Right Postest < E.Right Pretest b E. Right Postest > E. Right Pretest c E. Right Postest = E. Right Pretest Contrast Statistics
N 0 6 0 6
E. Right Postest - E. Right Pretest Exact Sig. (bilateral) ,031(a) a It has been used the binomial distribution b Sign test
The Wilcoxon signed-ranks test determined the existence of significant differences by comparing the effectiveness before and after the application of the proposal (0,028) under a signification level of 0,05. The Ranks established six positive values, showing an improvement in all the parameters evaluated after the implemetation of the coordination exercises. The Wilcoxon test and its frequencies strenghtened the previous statements, since the value of the bilateral signification was lower than the signification level expected (0,031). Table 9: Comparison of the effectiveness in the Backhand Hit technique before and after the application of the proposal. The Wilcoxon signed-ranks test.
Parameter
Effectiveness Before (Pretest) Effectiveness After (Postest) 28,57 55,00 55,56 69,57 Side Scrolling 70,00 76,47 Diagonal Scrolling Forward Movement 45,45 71,43 Backward Movement 73,91 81,82 Initial Position recovery 69,57 73,91 Split step
Ranks Average N Rank E.Backhand Negative Ranks 0(a) ,00 Postest Positive Ranks 6(b) 3,50 E.Backhand Draws 0(c) Pretest Total 6 a E.Backhand Postest < E.Backhand Pretest b E.Backhand Postest > E.Backhand Pretest c E.Backhand Postest = E.Backhand Pretest
Ranks Sum ,00 21,00
Contrast Statistic (b) E.Backhand PostestE.Backhand Pretest Z -2,201(a) Sig. Asym.(bilateral) ,028 a Base don the negative ranks. b Wilcoxon signed-ranks test Frequencies
E.Backhand Postest E.Backhand Pretest
Negative Differences(a) Positive Differences(b) Draws(c) Total
N 0 6
0 6 a E.Backhand Postest < E.Backhand Pretest b E.Backhand Postest > E.Backhand Pretest c E.Backhand Postest = E.Backhand Pretest
Contrast Statistics(b) E. .Backhand Postest - E. Backhand Pretest Exact Sig. (bilateral) ,031(a) a It has been used the binomial distribution b Sign test
As in the Forehand Hit technique, the Backhand Hit technique determine dan improvement in the six parameters (Positive Ranks) after applying the proposal of coordination exercises for a six-month period. The asymptotic significations was established in the Wilcoxon signed-ranks test in 0,028, lower than the signification level expected (0,05), for which significant positive differences are established for the postest, leading to an improvement of the sport performance in terms of coordination according to the results measured by the observers in competitions where the players of the study participated. On the other hand, the previous statements were reinforces by applying the Wilcoxon signed-ranks test, since both
the Frequencies (Positive Differences: 6) and the signification level (0,031) determined the positive values expected after the implementation of the proposal designed. For that reason, we agree with authors Meierhofer (1989), Torres & Carrasco (1998) and Zetou, Vernadakis, Tsetseli, Kampas, & Michalopoulou (2012) that the coordination capacity and its relation with the mobility is of great importance in the learning of the tennist player skills and their sport performance. For which the training of the athlete depends on the training level of the coordination capacities (Grosser & Schonborn, 2002; Bourqouin, 2003; Weineck, 2005; Knudson, 2006; Ivancevic & et al, 2010). Table 10: Level of reliability reached by the specialists OBSERVER
REFERENCE 1 2 3 4 5 6
COINCIDENCES
PERCENTAGE
MEDIAN
96,88% 98.44%
32 31 32 30 29 32 32 ARITHMETIC MEAN
100,00 96,88 100 93,75 90,63 100 100
Table 10 specific, based on the comparisons of the six specialist in relation with the expert specialist, an index of the measures of the central trend higher than 95 percent, (Arithmetic Mean: 96,88, Median: 98,44), inferring the existence of high reliability, with a margin of error of less than 5 percent. CONCLUSIONS The design and implementation of the specific coordination exercises has significantly contributed to increase the performance of the the forehand and backhand hitting techniques, as demonstrated by the Wilcoxon signed-ranks test
before and after applying the proposal. Therefore, the effectiveness increases in the movility or displacement of the tennis player based on coordination.
BIBLIOGRAPHY 1. Abernethy, B. (1988). The effects of age and expertise upon perceptual skill development in a racquet sport. Research Quarterly for Exercise and Sport, 59, 210-221. 2. Baiget, E., Iglesias, X., Vallejo, L. y Rodríguez, F.A. (2011). Efectividad técnica y frecuencia de golpeo en el tenis femenino de élite. Estudio de caso. Motricidad. European Journal of Human Movement, 2011: 27, 101116. 3. Bourqouin, O. (2003). Coordination. In: Strength and Conditioning for tennis, A.Q. Machar Reid, and Miguel Crespo. London, UK: International Tennis Federation, ITF Ltd, 71-77. 4. Calero, S. (2009). Sistema de registro y procesamiento del rendimiento técnico-táctico para el voleibol de alto nivel (Doctoral disertación, Tesis en opción al grado científico de doctor en ciencias de la Cultura Física. Departamento de Juegos Deportivos. Universidad de las Ciencias de la Cultura Física y el Deporte "Manuel Fajardo", La Habana. Cuba. 5. Calero, S. (2010). Las fórmulas estadísticas clásicas para procesar el rendimiento técnico-táctico del voleibol. Lecturas: Educación Física y Deportes, Revista Digital. Buenos Aires - Año 15 - Nº 144 - Mayo de 2010. Consultado:
20
de
Diciembre
del
2015.
http://www.efdeportes.com/efd144/rendimiento-tecnico-tactico-delvoleibol.htm 6. Calero, S. y González, S. (2015). Preparación física y deportiva. Quito, Ecuador: Editorial de la Universidad de las Fuerzas Armadas ESPE. 7. Calero, S., Suárez, C. y Fernández, A. (2012a). Determinación de las escalas de valores del rendimiento técnico-táctico ofensivo del voleibol cubano. Parte 1. Recuperado el 29 de Noviembre de 2015, Lecturas:
Educación
Física
y Deportes,
Buenos Aires,
Año
15, No:
166:
http://www.efdeportes.com/efd166/escalas-del-rendimiento-ofensivo-delvoleibol.htm 8. Calero, S., Suárez, C. y Fernández, A. (2012b). Determinación de las escalas de valores del rendimiento técnico-táctico ofensivo del voleibol cubano. Parte 2, Final. Recuperado el 29 de Noviembre de 2015, Lecturas: Educación
Física
y Deportes,
Buenos Aires,
Año
17, No:
167:
http://www.efdeportes.com/efd167/escalas-de-valores-del-rendimiento-delvoleibol-2.htm 9. Campo, V.L. (2008). Influencia del entrenamiento perceptivo, basado en la anticipación, sobre el comportamiento visual y la respuesta de reacción aplicado al tenis. Tesis doctoral, Universidad de Extremadura, España. 10.Coutinho, C. (2014). Physical Conditioning - Success in Tennis series: the science behind perfomance. Federación Portuguesa de Tenis. Portugal. 11.Coutinho, C. (2015). Success in Tennis: Science Behind Performance. Federación Portuguesa de Tenis. Portugal; p: 67-123. 12.FIVB (2003) CD-ROM- Top Volley: El juego masculino: Técnica y Táctica. Lausana. Suiza. 13.Flores, E.; Calero, S.; Arancibia, C. y García, G. (2014a). Determinación de parámetros básicos de aptitud física de la población ecuatoriana. Proyecto MINDE-UG. Recuperado el 29 de Noviembre de 2015, Lecturas: Educación Física
y
Deportes,
Buenos
Aires,
Año
19,
No:
197:
http://www.efdeportes.com/efd197/aptitud-fisica-de-la-poblacionecuatoriana.htm 14.Flores, E.; Calero, S.; Arancibia, C. y García, G. (2014b). Determination of basic parameters of physical fitness of Ecuadorian population. MINDE-UG Project. Recuperado el 29 de Noviembre de 2015, Lecturas: Educación Física
y
Deportes,
Buenos
Aires,
Año
19,
No:
196:
http://www.efdeportes.com/efd196/basic-parameters-of-physical-fitness-ofecuadorian.htm
15.Freo,
A. (1998).
Mil 500 ejercicios para el desarrollo de la técnica, la
rapidez y el ritmo en el tenis. Editorial Paidotribo, Barcelona, España. 16.Grosser, M. & Schonborn, R. (2002). Competitive Tennis for Young Players. Meyer & Meyer Verlag. USA; p:47. 17.Hurtado, C.R. (2011). El perfil técnico-táctico de los tenistas de la categoría 13-14 años de Villa Clara, como proceso esencial para individualizar su preparación. Lecturas: Educación Física y Deportes. EFDeportes.com, Revista Digital. Buenos Aires, Año 16, Nº 163, Diciembre de 2011. Consultado
el
día
10
de
Noviembre
del
2015
en
la
Web:
http://www.efdeportes.com/efd163/el-perfil-tecnico-tactico-de-lostenistas.htm 18.Iriarte, M.T. (2004). Situaciones críticas y no críticas de juego en tenis de competición el control de la acción deportiva y su influencia sobre el rendimiento. Un estudio de campo. Tesis Doctoral, Universidad Autónoma de Madrid, España. 19.Ivancevic & et al, (2010). Paradigm Shift for Future Tennis: The Art of Tennis Physiology, Biomechanics and Psychology. Springer Science & Business Media,. USA; p: 177-179. 20.Izquierdo, M. (2008). Biomecánica y Bases Neuromusculares de la Actividad Física y el Deporte / Biomechanics and Neuromuscular Bases of Physical Activity and Sport. Ed. Médica Panamericana. Madrid, España, p:105. 21.Kambas, Α., Fatouros, J., Aggelousis, Ν., Gourgoulis, V., & Taxildaris, Κ. (2003). Effect of age and sex on the coordination abilities in childhood. Inquiries in Sport & Physical Education, 1, 152-158 22.Knudson, D. (2006). Biomechanical Principles of Tennis Technique: Using Science to Improve Your Strokes. Racquet Tech Pub. USA; p: 59-70 23.Lacambra, D., Gimeno, F. y Colás, J. (2012). Diseño e implementación de un protocolo de evaluación de los partidos de tenis, en la etapa de tecnificación, en Aragón. Real Federación Española de Tenis, España.
24.León, S., Calero, S. y Chávez, E. (2014). Morfología funcional y biomecánica deportiva. Quito, Ecuador: Editorial de la Universidad de las Fuerzas Armadas ESPE. 25.Losada, J.L., Casa, C.A. y Árdá, A. (2015). Cómo mejorar la efectividad en un jugador de tenis. modelos de regresión log-lineales. Cuadernos de psicología del deporte, ISSN 1578-8423, Vol. 15, Nº. 1, 2015, págs. 63-70. 26.Mantis, K., Zachopoulou, E., & Mavridis, T. (1998). A battery of tests for evaluating abilities related to the tennis serve. Journal of Human Movement Studies, 35, 73-88. 27.Martin, J. (2011). The Best of Soccer Journal: An NSCAA Guide to Soccer Coaching Excellence. Meyer & Meyer Verlag. USA; p: 154-160. 28.McGarry, T., O’Donoghue, P. & Sampaio, J. (2013). Routledge Handbook of Sports Performance Analysis. Routledge. USA; p: 90-100; 214. 29.Meierhofer, E. (1989). La capacidad de coordinación en el tenista. Revista de EF Renovación de teoría y práctica, 28, 8-12. 30.Menayo, R. (2010). Análisis de la relación entre la consistencia en la ejecución del patrón motor del servicio en tenis, la precisión y su aprendizaje en condiciones de variabilidad. Tesis Doctoral, Universidad de Extremadura, España. 31.Moya, M., Bonete, E., y Santos-Rosa, F.J. (2010). Efectos de un periodo de sobrecarga de entrenamiento de dos semanas sobre la precisión en el golpeo en tenistas jóvenes. Motricidad. European Journal of Human Movement, 24, 77-93. 32.Nitsch, J., Neumaier, A., Marées, H. & Mester, J. (2002). Entrenamiento de la técnica: contribuciones para un enfoque interdisciplinario. Editorial Paidotribo,, Barcelona, España; p: 51. 33.Ortiz, R.H. (2004). Tenis: potencia, velocidad y movilidad. INDE, Barcelona, España; p: 23-275. 34.Reilly; T.; Hughes, M. & Lees, A. (2013). Science and Racket Sports I. Taylor & Francis. USA; p: 61-71.
35.Solanellas, F. (1999). Detección de talentos en tenis. Revista de Psicología del Deporte. Vol. 8, núm. 2, pp. 259-270. 36.Torres, G., & Carrasco, L. (1998). La coordinación como factor principal en la enseñanza del tenis. Habilidad Motriz, (12), 41-47. 37.Vasconcelos, A. (2000). Planificación y organización del entrenamiento deportivo. Editorial Paidotribo, Barcelona, España; p: 57. 38.Vergauwen, L., Madou, B., y Behets, D. (2004). Authentic evaluation of forehand groundstrokes in young low- to intermediate-level tennis players. Medicine and Science in Sports and Exercise, 36(12), 2099-106. 39.Vergauwen, L., Spaepen, A. J., Lefevre, J., y Hespel, P. (1998). Evaluation of stroke performance in tennis. Medicine and Science in Sports and Exercise, 30(8), 1281-1288. 40.Vila, C. (2006). Fundamentos prácticos de la preparación física en el tenis. Editorial Paidotribo, Barcelona, España. 41.Weineck, J. (2005). Entrenamiento total. Editorial Paidotribo, Barcelona, España; p: 516-531.
