Introduction
Fútbol, or soccer, is the most popular sport in the world, with an estimated 3.5-4 Billion fans (Wood, R., 2018). It is played worldwide by all ages because it is important to them. They see the health benefits that soccer brings to them along with it being fun for them as well. Some health benefits that soccer helps increase is cardiovascular exercise, improves muscle tone, flexibility, building strength, endurance and helps lower body fat as well. With the constant jogging, walking, and running, this helps improve and work the muscles and heart in multiple ways. There are four different phases when it comes to a soccer kick – back wing, leg cocking, leg acceleration, then the follow through. Back swing is the first motion in a soccer kick, it is when the body is preparing to build up its momentum to power through the rest of the other phases. Leg cocking is preparing the body to move forward. Leg acceleration is the speed building up to get ready and launch the ball. The motions of when it comes to the soccer kick may seem simple but once put into play, it is actually quite complex. Regardless the level of experience, all players will work on their soccer kick until perfected or until they are too tired to continue.
Literature Review
For thousands of years, soccer has been played for the love of the game, fitness, perseverance, leadership, and social activities. Throughout those years, players and coaches have studied, learned, and taught the fundamentals of the right soccer kick. In an article published by the J Sports Sci Med titled “Biomechanical Characteristics and Determinants of Instep Soccer Kick” explains the proximal-to-distal motions of the lower limbs, then the backward deceleration due to the backswing preparing itself for the forward acceleration of the full knee extension, and lastly, the follow through contact of the foot with the ball (Kellis, E. & Katis, A., 2007). This purpose behind this paper was to show that the speed, spin, and path of the ball highly depended on the excellence of the ball-to-foot contact (Kellis, E. & Katis, A., 2007).
The second article titled “Effects of combined strength and kick coordination training on soccer kick biomechanics in amateur players” focuses more of the coordination of the kick so that way the athlete can get the full explosive power and still increase muscle flexibility and strengthening with the proper techniques. The kicking movement that they worked on was divided into three different phases (Manolopoulos, E., Papadopoulos, C., & Kellis, E. 2006), the contact of the supported leg on the ground, then the smallest angle of the knee flexing from the supported leg that is in contact with the ground, and lastly, the swinging of the leg making contact with the ball (Manolopoulos, E., Papadopoulos, C., & Kellis, E., 2006). This article specified that the most important thing about a successful soccer kick is the speed at which the ball is traveling. Between all the segments in the leg, that enhanced the kick was the thigh kicking phase (deceleration) because it determined the acceleration of the full knee extension that is exerted.
This last article titled “Effects of an intermittent exercise fatigue protocol on biomechanics of soccer kick performance” explained more of the differences between each kick amongst players and recorded the fatigue levels based off how they each preformed the instep soccer kick repetitively after 10 kicks. Each amateur male soccer player was examined doing maximal instep soccer kicks prior to and after a 90-minute exercise protocol (Kellis, E. & Katis, A., 2006). The researchers learned that with the soccer kick performances had been impaired due to the simulation soccer game. It was clear that with the simulation had exhausted the players which affected the way they performed when it came to their instep soccer kick. Gradually their soccer kicks started to become slower but still had around the same distance depending on how strong their kick was.
Kinematic Analysis
For the kinematic portion of this essay, an article published by Bio Med Central titled “From 2D leg kinematics to 3D full-body biomechanics-the past, present and future of scientific analysis of maximal instep kick in soccer” will describe the broken-down phases of a soccer kick. Although, due to the nature of the sport, researchers had a more difficult time conducting research on the players because of the way they kick the ball. It makes it more challenging for the researchers since there is not exact body movement that a player needs to perform in order for the soccer kick to be completed (Shan Gongbing, & Zhang Xiang., 2011).
The first or initial phase when it comes to kicking a soccer ball is when the kicking leg is starting to wind backwards. When kicking leg winds backwards, reaches a maximum of hip hyperextension and knee flexion. As for the stable leg making contact with the ground, it becomes the leg that bears all the weight of the athlete. This phase is completed right before the kicking leg comes in contact with the ball. Once the kicking leg has come in contact with the ball, the second phase has begun (Shan Gongbing, & Zhang Xiang., 2011).
During this phase, the hips are flexed on both sides so that it can support the kicking leg along with the stable leg. In this phase, the kicking leg has reached full maximum knee extension prior to meeting with the ball. As for the supporting leg, that knee is slightly flexed so that when the kicking leg is accelerating forward it is getting ready to come in contact with the ball. This phase is considered completed once the leg is completely extended and hitting the ball (Shan Gongbing, & Zhang Xiang., 2011).
The follow through phase is the last phase for the instep kick. At this point the leg has reached maximum height right after coming in contact with the ball. The leg will swing through with the help of hip flexion so that the ball can reach maximum velocity and also acceleration. When the leg follows through after having contact with the ball, it helps with the ball to get off the ground and also less chances of the athlete getting hurt. Soccer players are susceptible to lower back injuries due to the lower back supporting all the weight and motion. The twisting motion in kicking can cause pressure on the lower back which can cause herniated discs, ligament tears, and back strains.
Throughout this entire process the body undergoes a numerous amount of angles, velocities and planes. For the first phase in the sagittal plane, the ankle is flexed in a plantarflexion movement (toes pointed). When it is plantarflexed, it is also slightly abducted at about 20 o (Kellis, & Katis, 2007). The knee follows with slight internal rotation, an angular velocity of 745-860 deg*s-1, a flexion of 114 o (Kellis, & Katis, 2007). Lastly for the first phase is the hip/thigh which is externally rotated and adducted.
The second and third phase also is involved in the sagittal plane but this is when the foot comes in contact with the ball then follows through. As previously stated, the ankle is in plantarflexion, so it continues to stay in this flexed motion throughout the kick. However in this phase, the knee has reaches maximum extension with an angle of 0 o (Kellis, & Katis, 2007). In the previous phase, the hip was externally rotated and adducted but in this last phase it is still externally rotated, adducted but now also flexed. The thigh is flexed with a velocity of 745 deg*s-1, but only a small angle of 20 o (Kellis, & Katis, 2007).
Discussion
The main finding between these studies is that with the combined strength and kicking exercise protocols combined called for a longer and higher ball velocity. The soccer ball can also travel faster due to the way the athletes came in contact with it. If the athletes did not hit it on the precise area of the foot, then it would show based off of how the kick turns out. Both literature reviews proved that there is much more when it comes to the instep soccer kick. To the naked eye, it seems easy and can be done but for it to be done correctly is what becomes more challenging for someone who has never played soccer before.
When it comes to the angular velocities of the ball, the hips and the knees play a huge role when it comes to the increasing velocity and acceleration. Although this is true, it is actually the knee in which is the most important aspect of the instep soccer kick. The knee has more flexion and extension than the hip giving it the ability to have more of an angular velocity. However, it is the hip or thigh that is the strength of the knee. The hip is what brings the whole leg, including the knee, to a full extension from flexion. The knee is the added momentum that is coming from the base of the hip (Riyajuddin, M., & Khan, 2011).
Conclusion
Based off all the given information from studies and research, the instep soccer kick proves to be a complex, tiresome, and beautiful play. There is no exact way to perform a soccer kick but there are basic fundamentals that must be achieved when doing the actual kick. These rudiments are needed so that the athlete can perform well and prevent the risk of injury. When a person can understand the phases of the backwind, coming in contact with the ball, then following through the kick with the ball, then the athlete will succeed with a powerful kick. With practice, patience, and the knowledge of this technique becomes easier and more accurate in making the kick flow better to improve the athletes and soccer in itself.
References
Kellis, E., & Katis, A. (2007). Biomechanical characteristics and determinants of instep soccer kick. Journal of sports science & medicine, 6(2), 154-65.
Kellis, E., Katis, A., & Vrabas, I. S. (2006). Effects of an intermittent exercise fatigue protocol on biomechanics of soccer kick performance. Scandinavian Journal of Medicine & Science in Sports, 16(5), 334–344. Retrieved from https://lopes.idm.oclc.org/login?url=http://search.ebscohost.com/login.aspx?direct=true&db=s3h&AN=22308208&site=eds-live&scope=site
Manolopoulos, E., Papadopoulos, C., & Kellis, E. (2006). Effects of combined strength and kick coordination training on soccer kick biomechanics in amateur players. Scandinavian Journal of Medicine & Science in Sports, 16(2), 102–110. Retrieved from https://lopes.idm.oclc.org/login?url=http://search.ebscohost.com/login.aspx?direct=true&db=s3h&AN=20042570&site=eds-live&scope=site
Mohammad, A., Riyajuddin, & Khan, J. (2011). A KINEMATIC STUDY OF INSTEP SOCCER KICK AT CONTACT PHASE. International Journal Of Sports Sciences & Fitness, 1(2), 101-110.
Shan Gongbing, & Zhang Xiang. (2011). From 2D leg kinematics to 3D full-body biomechanics-the past, present and future of scientific analysis of maximal instep kick in soccer. Sports Medicine, Arthroscopy, Rehabilitation, Therapy and Technology (SMARTT), Vol 3, Iss 1, p 23 (2011), (1), 23. https://doi-org.lopes.idm.oclc.org/10.1186/1758-2555-3-23