Journal of Advanced Social Research Vol.4 No.7, July 2014, 13-18

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Effect of plyometric exercises on development of explosive power and some of biochinematic variables for jumping through attack serve performance in volleyball Article Info Received:05.

1 Effect of plyometric exercises on development of explosive power and some of biochinematic variables for jumping through attack serve performance in volleyball Article Info Received: Accepted: Published online: Suhail Jaseem Al-Misslmauy Faculty of Physical Education-University of Babylon ABSTRACT: The aim of this study was to know effect of Effect of plyometric exercises on development of explosive power and some of biochinematic variables for jumping through attack serve performance in volleyball. 10 young players aged (18-19) year from Al-Raudhatain club were participated in present study and the researcher used experimental method design with one experimental group which depend on pre and post-tests because it is suitable to the nature of the study, measurements were achieved for all the tribal members of the research subject in the period from 8/7/2011 to 12/7/2011 whereas the proposed training program was applied in the period from Saturday, 16/07/2011 to Wednesday, for (8) weeks, three training units a week and the total of units twenty-four unit training. Data were analyzed by SPSS program and paired sample T-test was used to compare mean of previous and post of information. Study concluded that a significant change was observed on developing explosive power of the legs and horizontal speed for takeoff, maximum flight time and vertical height through flight. Finally, researcher recommended the need to use proposed plyometric exercises on development of the explosive power of the legs, as well as exercises must be similar to the motor tracks of the skills and the need to conduct similar studies with the other age groups. Key Words: plyometric exercises, explosive power, Biochinematic variables, attack serve, volleyball. 1. Introduction: Volleyball considers one of the most important games which occupies a prominent place among the sport games, where practiced with all ages and it contains compound and a variety of skills. However, it seems to be easiest games in terms of performance, while the researcher sees it is the most difficult game in which advanced player can be developing due to the many variables that player faces them through the performance where the player must make in the performance of most of the skills and especially attack serve at the moment upgrading to convert horizontal speed of the body gravity center to vertical velocity at the lowest possible loss in gained speed from approaching (approaching steps). So the researcher sees that jumping and flight are representing one important phase and interrelated to service motor task. However, the 31

2 importance of study is to make a serious attempt to develop a jump phase of attack serve skill of the mechanical side (which is the most important signs to develop the performance fully), due to attack serve skill has four motor performance stages (Approaching steps, jump, kick the ball, and landing) where jumping phase is one of basic technical stages and also it is the most important factor during perform the main part since there must be a big explosive ability help player to reach the highest vertical jump so it could use some indications of mechanical that reflect the development of the level of performance (horizontal speed - vertical height - time of flight) when the performance of the skill as an indicator of the evolution of the explosive power of the legs, as well as the ability of player in the recruitment of this effort to improve the level of achievement. It is through the experience of the researcher noted that the phase of upgrading (jumping and flight) does not allocate sufficient time within the training programs for the youth teams in addition to the omission of some of the coaches of the training associated with the physical side shareholder in upgradable, so it can be summarized research problem in being a scientific attempt directed towards the study of the impact of the program suggested training for the development of explosive power of the legs and some of the chinematic variables (horizontal speed - vertical height - flight time) by using plyometric exercises on the flight path in attack skill of the volleyball players. So the aim of this study was to know effect of Effect of plyometric exercises on development of explosive power and some of biochinematic variables for jumping through attack serve performance in volleyball. 2. Methodology: 2.1 Subject: 10 young players aged (18-19) year from Al-Raudhatain club were participated in present study and the researcher used experimental method design with one experimental group which depends on pre and post-tests because it is suitable to the nature of the study, Table (1) showed a description of study subject. Table (1) shows characteristics of study subject. Basic variables Measurement Unit Mean SD Skewness Coefficient Age Month Height Cm Weight Kg Length of lower torso Cm Training program: Measurements were achieved for all the tribal members of the research subject in the period from 8/7/2011 to 12/7/2011 whereas the proposed training program was applied in the period from Saturday, 16/07/2011 to Wednesday, for (8) weeks, three training units a week and the total of units twenty-four unit training. 31

identified the suitable variables for the study which is horizontal speedmaximum flight time- vertical height.

3 2.3 Used tests: Biochinematic variations identify of jumping accompanied for the attack serve in volleyball. Researcher prepared a questionnaire including set of biochinematic variations for jumping accompanied to attack serve, the questionnaire was reviewed by some of experts and specialists where they identified the suitable variables for the study which is horizontal speedmaximum flight time- vertical height. Researcher filmed three attempts for each player in pre measurement and three attempts in post attempts after applied the program, the researcher then chose the best attempt in pre measure and also in post measure and we extracted during analysis process following things: horizontal speed for takeoff, maximum flight time and vertical height through flight. 2.4 Statistical analysis: Data were analyzed by SPSS program and paired sample T-test was used to compare mean of previous and post of information and we also used mean, standard deviation, and skewness coefficient. 3. Results and discussion: After researcher conducted the data which was gotten, he showed, analytical, and discusses the study results as following. Table (2) shows statistical treatments to the study variables for pre tests Variables Mean SD Vertical jump from stable (cm) Maximum vertical height (cm) Flight time (Second) horizontal speed for takeoff (M\S) Table (3) shows statistical treatments to the study variables for post tests Variables Mean SD Vertical jump from stable (cm) Maximum vertical height (cm) Flight time (Second) horizontal speed for takeoff (M\S)

4 Table (3) showed means and standard deviations of post measurements for study subject, table (2) and (3) showed a different means and SDs values between pre and post measurements so the researcher used T test to know the effect of suggestion training in study variations. Table (4) shows means, standard deviations, calculated and tabulated T for study variations. Variables Pre test Post test T test Mean SD Mean SD Vertical jump from stable (cm) *..99 Maximum vertical height (cm) Flight time (Second) Horizontal speed for takeoff (M\S) * * * 0.00 Tabulated T value at the level of significant (0.05) and freedom degree = 2.36 Significant differences were showed between pre post tests for all study variables in favor of post-tests where calculated T value was (5.22) for vertical jump and (14.74) for maximum vertical height and (6.35) for flight time, finally (6.66) for horizontal speed for takeoff moment, so they are all larger than tabulated T value which is (2.36) at the level of significant (0.05). It means there was a development in explosive power and biochinematic variables as a result of effect of suggestion exercises which placed by the researcher and this refers to important of use a plyometric training. The different between pre and post-tests in vertical jump variable refers to activated and rationing of plyometric training in improve the motor and skills capacities, these findings are consistent with the view that there are many types of plyometric training confined in partridges and leaps on the barriers, defections, and deep jump in order to develop explosive power of the legs, given the results of the high response which is illustrated through vertical jump test (Marwan., 2001). It is worth mentioning that plyometric training showed some indications in the physical test (vertical jump) and considers a key touchstone for assessing the progress in plyometric training (Mokhtar., 1989). The sound rationing of plyometric training working to increase the explosive power of the legs, which is required for skill performance, especially if the exercises very similar to the circumstances of the performance of the skill and in its route and the nature of their 30

5 performance, which require the integration of speed with strength to achieve high performance ability, such as what happens in the jump phase during competition (Marwan., 2001). Looking at the "horizontal speed through takeoff" variable, we find that the player is at his performance of jump accompanied to attack serve trying to achieve the highest vertical rise as possible as can to get the highest flight point. this is governed by two main variables one of them horizontal speed and momentum from which player stems from the earth to achieve phase of flight. Given, if momentum is increased will help player to achieve the maximum vertical height during the flight path, as the increase in the distance of the long jump is defined by three essential elements of a horizontal speed and vertical velocity and high center of gravity of the body during the upgrade, which is affected by force affecting resulting from the upgrading (Ballesteros, Alvarez., 1991). Flight time Regards the second variable is a (time of flight), we found if the difference between leaving the ground and landing is increased the time of player s flight will be increased well to move his body in different situations suitable the movement to perform private motor task for an attack serve and thus increased the chance of his movement under the influence of the vehicle horizontal velocity, thus increasing the distance additional horizontal, which earned the starting level, Talha et al., 1998 has been confirmed the important of flight time. The third variable is vertical jump from stable, where height equivalent to multiplying (speed x time) which can t be achieved just by the player who has a high capacity in the vertical jump to the top of which benefit the volleyball player while pressing to earn a good height to qualify for aviation and this depends on the explosive ability of player s legs that enjoyed. Regards fourth variation which is maximum vertical height while flight, we see that the maximum vertical height during the flight path allows the performance of a good technic while the phase of flight in preparation for motor task which is important to hit the ball and then the landing phase, the significant increase in the height of the moral center of gravity may be due to three points are: - The increase in the angle of departure. - The increase in the height of the body gravity center before leaving the ground directly. - The increase in the accelerate on the horizontal axis to the gravity center point during departure directly (Talha et al., 1998). Based on the above can take advantage of the development of explosive power of the legs in the suggestion program in the skill of attack serve that requires during performance a high capacity such as what happens at the stage of takeoff, the proposed program by using the plyometric exercises may characterize the nature of exercises used as designed in the direction of the nature of the performance of the skill which works to raise the skill and physical level incident in the level of skill performance. 4. Conclusion: Study concluded that a significant change was observed on developing explosive power of the legs and horizontal speed for takeoff, maximum flight time and vertical height through flight. Finally, researcher recommended the need to use proposed plyometric exercises on development of the explosive power of the legs, as well as exercises must be similar to the motor tracks of the skills and the need to conduct similar studies with the other age groups. 37

6 References: Ballesteros, Alvarez., (1991). Foundations and principles of education and training in athletics, the International Federation of Athletics, Center for Regional Development in Cairo, 297. Bonnette, R. Spaniol, F. Melrose, D. Ocker, L. Bain, J. (2011). The Relationship Between Squat Strength, Vertical Jump, and Power Score of High School Football Players. Journal of Strength and Conditioning Research, 25 (7) Channell, Brian. Barfield. (2008). Effect of Olympic and traditional resistance training on vertical jump improvement in high school boys. Journal of Strength and Conditioning Research, 22 (5): Hussein Ali and Amer Luxury. (2006). Plyometric exercises explosive power, Baghdad, Karar Printing Office, Marwan Abdul Majeed and Mohammed al-yasiri. (2004). Recent trends in athletic training, Oman, Warraq Foundation Publishing, Marwan Abdul Majeed., (2001). Scientific Encyclopedia volleyball, skills, plans, physical and skill tests, physical measurements, the selection of the disabled, arbitration, Oman, Warraq Foundation for publication and distribution, 1:81. Mokhtar Salem., (1989). Origins volleyball, Beirut, Dar School Knowledge, 76. Talha Hossam El Din Hussein., (1994). Foundations kinetic functional sports training, Dar Al- Fikr Al Arabi, Cairo, 125. Wajih Mahjoub. (2002). Research and curricula, Baghdad, Library of Printing and Publishing,

Faculty of Physical Education & Sport Sciences, Diala University. Seif El Din Watheq :

Faculty of Physical Education & Sport Sciences, Diala University. Seif El Din Watheq : THE EFFECT OF COMPARATIVE COMPETITION METHOD DUE TO SOME KINEMATIC VARIABLES ON CORRECTING SOME MOTOR PERFORMANCE ERRORS IN SHOOTING FROM OVERHEAD FOR THE 3RD STAGE STUDENTS Shaimaa Sami Shehab a Seif