Analyzing, investigating and calculating the optimum mode of the parameters affecting the record of the javelin throw including the initial velocity, initial angle, and initial height of throw

Turk J Kinesiol 2019; 5(1): 1-14 www.dergipark.gov.tr/turkjkin Original Research Analyzing, investigating and calculating the optimum mode of the parameters affecting the record of the javelin throw including the initial velocity, initial angle, and initial height of throw Samaneh Mohammadia 1, Yousef Jalalabadi 1, Fateme Nikkhoo Amiri 2 Department of Engineering, Kashmar Branch, Islamic Azad University, Kashmar, Iran. Department of Corrective Exercise, Physical Education and Sports Sciences, University of Tehran, Tehran, Iran. 1 2 Abstract. The javelin throw is a track and field event, which is of very great antiquity. The most important goal in the javelin throw is the throwing record. In the javelin throw, three factors (initial velocity V1 , initial throw angle 1 and initial throw height H) play a fundamental role in an athlete's record. Throwing record only depends on these three factors, but of course each of them alone is subject to various factors at the time of throwing: the place, time, environmental and physical conditions of an athlete. In this study, these factors were expressed, analyzed and investigated, and the physical, technical and computational parameters with greater precision (from the perspective of sports engineering) were also expressed, and thus the optimum modes for each of them were obtained. The initial throw velocity (V1), initial throw angle (θ1), initial throw height (H), their roles in throwing record and the technical parameters affecting them have been investigated. Results show that the equations of optimum modes were obtained for the three aforementioned variables. Depending on a series of specific initial values for each athlete, an optimum mode of initial velocity, initial angle and initial height of throw were obtained for each athlete, resulting in the maximum record for throwing. Keywords. Initial height, initial velocity, sports engineering, javelin throw. Introduction The javelin throw is a track and field event, which is of very great antiquity. In considering the records achieved in the javelin throw, a remarkable advancement with the passage of time is seen, and this record increase is not because of the increase in the people's strength at the present time compared to the past, but as a result of more precise studies and an engineering view on this movement, so that higher records are achieved by fixing the defects in the movement and using the appropriate techniques, and this process is continuous. However, the scrupulous investigation of each science and the relationship between that science and other sciences within the scope of application is called the engineering of that science. Countries, which invest in this regard (sports engineering), will make a significant progress in athletic fields and records. The current century is that of technology and the era of computer and space and as such, one cannot be oblivious to this fact and act traditionally. The technique of a projectile motion plays an important role in achieving a record (Dai et al., 2013), and in some situations, by observing a proper technique Received: January 23, 2019 - Accepted: March 13, 2019 - Published: March 30, 2019 To cite this article: Mohammadi S, Jalalabadi Y, Amiri FN. Analyzing, investigating and calculating the optimum mode of the parameters affecting the record of the javelin throw including the initial velocity, initial angle, and initial height of throw. Turk J Kinesiol, 2019; 5(1): 1-14. Y. Jalalabadi, e-mail: DOI: 10.31459/turkjkin.516625 Analyzing, investigating and calculating the optimum mode of …. even by athletes having greater physical strengths, can be overtaken, as experience confirms this fact. Thus there are heroes in this field who do not have extraordinary strengths, but have achieved very good records (Dai et al., 2011). In order to be able to find appropriate techniques for athletes, this sport need be observed from the engineering perspective. Methods Projectile motion is a form of motion in which an object (projectile) moves along a parabolic path. Generally, in the javelin throw, three factors (initial velocity V1, initial throw angle θ1 and initial throw height H) play a fundamental role in an athlete's record. And to achieve greater records in the javelin throw, there is a need to increase the speed of throwing, by the upper limbs, in a series of continuous and consecutive movements (Dai et al., 2013; Leigh et al., 2008; Leigh et al., 2010; Leigh et al., 2013). Conversely, throwing record only depends on these three factors, but of course each of them alone is subject to various factors at the time of throwing: the place, time, environmental and physical conditions of an athlete (Dai et al., 2013; Leigh et al., 2008; Leigh et al., 2010). In this study, the optimum modes were achieved for athletes by calculation and from an engineering perspective (depending on the place, time, environmental and physical conditions of athletes), and were placed at their disposal to 2 achieve the maximum possible record; which in their capacity, depend on the place, time and circumstances. As shown in Figure 1, not only does each of the effective parameters depend on some factors, but they also have relationships with each other, and thus obtaining the optimum mode of one of the parameters may cause a decrease in some other parameters and consequently cause reduction of record, therefore, the optimum mode of all three parameters should be obtained simultaneously. For this purpose, first, the optimum modes of each parameter were investigated, and in the end, intersection points of these parameters were located, by drawing diagrams. In a research on the relationship between the diversity of techniques and the performance presented by the elite javelin throwers during the match, a negative correlation was observed between the diversity of technique and the performance in men throwers, but it was not the case in women throwers. Thus, the more uniform movement pattern is used by men in throwing, the better records they achieve, depends on the throw angle, the arm length, the initial throw velocity and in general, their techniques (Dai et al., 2013). Procedure To obtain the formula for the range of a projectile (record), there are two methods used, one of which has been proven: Figure 1. Effective parameters depend on some factors. Turk J Kinesiol 2019; 5(1): 1-14 3 Mohammadi et al., 2019 In this method, the equations of projectile motion are used and are shown as follows: 1 2 gt  V1 y t  y 0 , V1 y  V1 sin(1 ) , 2 1   H   gt 2  V1 sin(1 )t  0  2 1   gt 2  V1 sin(1 )t  H  0  2 y V1 sin(1 )  V 21 sin 2 (1 )  2 gH  t  R  V1 cos(1 )  R g , V1 sin(1 )  V 21 sin 2 (1 )  2 gH g , y0  0  R  V1x t  V 21 cos(1 ) sin(1 )  V1 cos(1 ) V 21 sin 2 (1 )  2 gH g R V1 cos(1 ) ( V1 sin(1 )  V12 sin 2 (1 )  2 gH ) g According to the final equation (Equation 1), it ca (...truncated)