THE RELATIONSHIP BETWEEN PHYSICAL FACTORS TO AGILITY PERFORMANCE IN COLLEGIATE TENNIS PLAYERS

THE RELATIONSHIP BETWEEN PHYSICAL FACTORS TO AGILITY PERFORMANCE IN COLLEGIATE TENNIS PLAYERS Ian McKinley and Dr. Kimitake Sato, Department of Exercise and Sport Sciences, College of Education, East Tennessee State University, Johnson City, Tennessee Tennis players change direction numerous times within a tennis match and game making agility an important skill for them to possess. The purpose of this study was to investigate the significance of physical factors as they relate to agility performance in collegiate tennis players. The physical factors looked at were anthropomorphic measurements; isometric peak force, rate of force development, countermovement jump, and squat jump performance. The participants were seventeen (Male: N = 8, Female: N=9) NCAA Division I collegiate level tennis players. Anthropomorphic measurements included height, body mass, and body fat percentages were also considered. Strength and power were measured by an isometric mid-thigh pull, and power was measured by vertical jumps. Significance was set at 0.05 for statistical analysis. Correlation analysis showed that isometric rate of force development from isometric mid-thigh pull was significant (p = 0.033). In conclusion both anthropomorphic measurements and vertical jump performance have very small relationship with agility performance but the rate of force development in the isometric mid-thigh pull test has statistically significant relationship to agility performance in tennis players, indicating agility movement is influenced by how fast you can develop force against ground. INTRODUCTION In collegiate tennis there were 10,018 men and 10,648 women in play across all division during the 2013 season, for a total of 20,666 athletes during this season ( retrieved from scholarshipstats.com). As well as being widely played sport, tennis is a unique sport that involves various movements to complete many quick starts and stops (i.e., acceleration and deceleration), repetitive overhead motions, and many different types of strokes. Additionally this game can be characterized by shifts from brief periods of maximal or near maximal work to longer periods of moderate or low intensity activity. The duration of a tennis match is often more than an hour and in some cases more than five hours even though rallies typically only last around five to seven seconds, and within this time frame a tennis player will on average run three meters per shot and a total of eight to twelve meters per point. Along with this intense aerobic activity players will often complete three hundred to five hundred high intensity efforts during a best of three sets match. During an average match a tennis player will complete around four directional changes per point, (Fernandez et al, 2006). These directional changes can be further broken down into three categories as tennis players move 1) forward forty-seven percent of the time, 2) sideways forty-eight percent of the time, and 3) backwards five percent of the time, (Parson & Jones, 1998). Within a regular match of two sets there is generally forty-eight points scored and during a Grand Slam match with three sets there are seventy-two points scored. This results in around one hundred and ninety-two directional changes in a regular match and around two hundred and eighty-eight directional changes in a Grand Slam match. These directional changes are in addition to the roughly three hundred and eighty-four five hundred and seventysix meters that players will be likely to run during a regular match and the five hundred and seventy-six to eight hundred and sixty-four meters that are run in a Grand Slam. Therefore this information implies that agility is a very important component for tennis players to develop to improve the quality of their play. In light of this information the purpose of this study was to investigate physical factors that relate to agility performance for competitive level of collegiate tennis players. The hypothesis going into these tests is that the power and speed of force production variables will have significance to the superior agility performance of the tennis players since there is a more directional changes over a shorter distance than in sports like soccer so the ability to decelerate and then reaccelerate again in a new direction is important for performance. REVIEW OF THE LITERATURE Agility Movements Agility is an important aspect for athletes across a broad range of sports and can often be used to separate elite athletes from sub-elite athletes. However to begin to understand the aspects of agility and how to test and train this component one must be able to define what is agility. Such a definition is made difficult though by how many different components that agility can include or be defined as depending on the perspective of the author. For example agility has been simply defined as the ability to quickly and accurately change direction (Young, et al., 2005). While this is the most simple and widely used definition for agility this fails to recognize some the cognitive aspects involved in agility. Further conflicting the goal of a common definition has been the relatively recent use of the term quickness in addition or as a replacement to agility. Quickness has come to be defined as a multiplanar or multidirectional skill that encompasses acceleration, explosiveness, and reactiveness (Parsons & Jones, 1998). Despite being used interchangeably for agility and even recommended training drills to increase this specific skill it must be noted that quickness can be seen as a component of agility itself since the common definition for it does include changing of direction or deceleration (Young, et al., 2002). Because of all of these interrelated components agility could only be described as the physical qualities it takes to be able to rapidly change direction or as the visual, processing, and decisionmaking abilities it takes to appropriately react and change direction to a stimulus. The previously mentioned process could also be expanded to include the technique and learning and retention process an athlete needs to be able to agile. Agility Movement Used in Sports In light of all of these interrelated components that can make up agility some very comprehensive definitions of agility have been proposed. One example of this comprehensive definition for agility was done by Chelladurai (1976). Chelladurai (1976) proposed a definition that would capture the perceptual and decision-making components involved in many competitive sports and thus defined four different categories that agility tasks could be placed. The first of the four categories are simple agility tasks, which he defined as being a pre-planned activity that is initiated by the athlete; therefore in this category the stimulus is the athlete’s environment and own movement. Second, is the temporal category of agility performance which consists of an athlete’s pre-planned response to an uncertain stimulus; such as a starter’s pistol or the referee’s whistle. The next category is spatial agility where the athlete has spatial uncertainty but temporal certainty. What these spatial and temporal confidence and lack of confidence translates into is that the athlete has a lack of knowledge about their action in response to a known stimulus. For example, this type of scenario can be seen in tennis where an athlete is receiving a serve and has knowledge of the time frame that serve will be completed but does not know where the serve will be directed on the court. Lastly, Chelladurai (1976) set out a universal category of agility in which there is both spatial and temporal uncertainty. This type of scenario can be seen in many team sports where during the plays the athletes cannot predict with certainty where or when the other players will move on the field. From this comprehensive definition it is easy for one to infer that both the spatial component of rapidly changing direction and the temporal component in which athletes go through perceptual factors and decision making occurs. However these two main components can be even further broken down into the factors that can relate to agility performance. This level of division is where factors like anthropometry, technique, sprint speed, muscle qualities, visual scanning, pattern recognition, and anticipation reveal their connections to agility skill. Agility Performance Since agility is related to so many different factors the term is used by many to describe any action that requires a rapid change of direction. Therefore agility has been used to describe sprints with planned directional changes but at the same time reactive evasion drills for team sports are also referred as agility drills. Such a liberal use of agility in describing these different actions can lead to further confusion. This time the confusion is due to inability to differentiate and specifically target the training factors that relate to agility performance. To try and alleviate some of this confusion Sheppard and Young (2005) attempted to develop a new and simpler definition that focused on the reaction to a stimulus component of agility performance. The new definition by Sheppard and Young (2005) defines agility as a rapid whole-body movement with change of velocity or direction in response to a stimulus, and in this way removes the classification system that Chelladurai created (1976). According to this new definition closed skills that involve a pre-planned action to a stimulus would be excluded from being called agility tasks. Additionally cone drills that are used many times for agility tests do not meet this definition of agility since there is no stimulus that the athlete is reacting to in this scenario. As a result this new definition requires the completed action to be an open skill to be counted as an agility task. As a result of the difficulty in finding a common definition and use for agility there tend to be two