Ovidius University Annals, Series Physical Education and Sport / SCIENCE, MOVEMENT AND HEALTH Vol. XI, ISSUE 2 Supplement, 2011, Romania The JOURNAL is nationally acknowledged by C.N.C.S.I.S., being included in the B+ category publications, 2008-2011. The journal is indexed in: Ebsco, SPORTDiscus, INDEX COPERNICUS JOURNAL MASTER LIST, DOAJ DIRECTORY OF OPEN ACCES JOURNALS, Caby, Gale Cengace Learning 374 COMPARATIVE STUDY ON THE EVALUATION OF THE ENERGETICAL PARAMETERS WHILE PERFORMING A VERTICAL JUMPING ON BOTH LEGS MEREUTA CLAUDIU 1 , TALAGHIR LAURENTIU 1 , MANOLACHE GABRIEL 1 , ICONOMESCU TEODORA 1 Abstract Purpose. The paper presents different methods used for evaluation of the average power as energetical parameter on vertical jumping on both legs. The average power is calculated using Lewis’s, Harman’s, Johnson’s & Bahamonde, Sayers’s and Georgescu’s formulas. A comparative analysis is performed. Theoretical concepts. The average power can be calculated using different formulas experimentally determined, using either the mass and the vertical jump height, or the flight periods of time and the periods on the ground. Different formulas were used as follows: - Lewis’s formula uses the mass and the jump height as input data; - Harman’s formula provides the average power and the peak power, using regression method; - Johnson’s and Bahamonde formula uses the mass, the jump height and the athlete’s height as input data; - Sayers’s formula provides the average power using the same input data as Lewis, but with different coefficients; - Georgescu’s formula is based on Bosco’s theory and it uses the flying times and ground times as input data. Conclusions. In order to get the average power developed by an athlete while performing vertical jumping on both legs, we can use different experimental methods. For each method, we can reveal the input data and the energetical parameters provided by the experiment (the average and the extreme values). The input data are different from one method to another. Most formulas are based on the vertical jump height and on the athlete’s mass, except for the MGM formula which is based on the flying times and times on the ground. The average power as energetical parameter provides an accurate evaluation of the ratio force-power which is very important as training parameter. The training process can be oriented to render the value of this ratio optimum. Key-words: energetical parameters, average power, vertical jumping. Introduction Experimental measurements and investigations are considered to be a real process of objective research of the qualitative and quantitative aspects of any phenomena or process. Sports science has its own patrimony of means and methods of investigation, which provides useful information that can be adapted to specific necessities. As the performances are higher and higher and the athletes’ body is subjected to efforts bigger and bigger, it is necessary to improve the methods of investigation, to render their results more realistic and to establish mathematical models that describe more and more accurate their performances. It is important to estimate the average power developed by an athlete in order to conduct his training to a better performance in sport (F.W. Dick, 2003). The trainers, the MD’s and other specialists involved in training process need realistic data that can ensure an exact and rigorous training process. The importance of measurements and investigations in sports The main issues that reveal the importance of experimental data in sport science and training process are:  The necessity of estimating and characterization of the athlete, of the sport field;  The necessity of comparison between two stages of training;  The necessity of determining the contribution of each component to the performance;  The necessity of revealing the causes of mistakes and the errors, in order to eliminate them or to reduce their effects. To be effective, the experimental measurements must meet the following requirements:  To be adequate to the purpose, to correspond to the structure of motion; 1 “Dunărea de Jos” University of Galaţi, ROMANIA Email: claudiu.mereuta@ugal.ro Received 19.04.2011 / Accepted 22.06.2011