The Bio Mechanics of a Ski Jump - Research Paper Example

Topic The Bio Mechanics of a Ski Jump In ski jumping, the ability of controlling posture and movement are the important demands that an athlete is required to meet. Like any other competitive sport, Olympic ski jumping is founded on the platform of moving faster, jumping higher and leaping further. Among others, biomechanics is an important factor in winning or losing an event in ski jumping. Low body weights, aerodynamic qualities of the equipments in use in addition to the natural abilities of the athlete are the critical aspects that influence performance in a particular ski jumping event. This paper is a qualitative analysis of the biomechanical forces of three important stages of Olympic ski jumping: in run, in flight, and landing. A list of the muscles and joints used in each phase are also included. In Run In order to gain optimal in-run speed, the ski jumper focuses on maximizing acceleration through keeping the friction between him and the skies and snow at the lowest possible minimum as well as the aerodynamic drag. This is in view of the fact that high in-run speed greatly influences the length of the jump that the athlete is going to make. The posture of the athlete and his/her dressings during the in-run phase are the key factors in minimizing the aerodynamic drag. Since during the in-run stage the athlete assumes a curved posture, there is centrifugal force acting on him, which he has to counter (Muller 268). Because of the muscular forces the athlete exerts, the in run phase is followed in a quick succession by a perpendicular acceleration towards the ramp. At the in-run phase, which takes about 0.3 seconds, the ski jumper generates optimal momentum that is perpendicular to the ramp in order to attain a good take-off angle. At the same time, the ski jumper is required to generate forward angular momentum so that he can take off with a good angle upon leaving the ramp. A low forward angular momentum results in a poor flight angle that in turn reduces velocity making the performance of the athlete very poor. Too high forward angular momentum on the other hand, comes with the risk of falling (Muller 268). The joints involved at this phase are joint center at the elbow hip joint while the muscles are the elbow flexor muscles, forearm muscles, hip joint muscles, takeoff leg, quadriceps muscles of the take-off leg joint center at the elbow and forearm muscles knee-extension muscles. Figure 1: An anticipated action of the arm to produce sudden un-weighting during ski jumping take off In Flight During flight, three important forces act on the athlete; gravitational force, the drag force, and the lift force. Through altering his posture however, the ski jumper can manipulate these three aerodynamic forces in a great way. By having an effect on the torque, the drag force, and the lift force, this athlete can significantly change the position of his flight with reference to air stream. It is important to point out that the human body assumes a complex structure in an air stream. In this regard, the implication of lift and drag forces on a ski jumper during the flight stage is not properly documented. An analysis of the aerodynamic data however shows that these two forces are of similar magnitude and that the length of a ski jumper’s flight is significantly influenced by a change in either of the two forces. The aerodynamic forces depends on the ski jumper’s position of flight and the features of the equipments that are in use. These two forces are important factor in competitive performances and it is left upon the athlete to influence them. As such, the ability of an athlete to reproduce his/her style of flight is what differentiates him/her from the rest. During the flight phase of a ski jumper, the density of air is relative to the aerodynamic forces. The best ski jumpers are capable of adjusting their style of flight to the conditions of thin air, subsequently maximizing their jumps and ensuring stability in their flights. During flight, the hip joint and its respective muscles are involved in addition to the joints and muscles of the legs. Figure 2: A ski jumper in flight In Landing One can appreciate the forces that act on the ski jumper athlete on landing by applying Newton’s second law of motion. A number of factors influence the normal force exerted by the ground on the ski jumper during landing: contraction of the legs, forward momentum, softness of the ground, and the angle of the surface on which one is landing. Depending on their appearances, these factors can reduce or increase the landing force of the ski jumper. Elite ski jumpers are able to make a good choice of jump geometry that results to a landing force equal to the way they would feel if they just stood at the point of landing, regardless of the height they have jumped. The muscles involved in this case are knee extension muscles, hip joint and its muscles and the muscles and joints of the legs. Figure 3: the four specific stages of a higher jumper; in run, take-off, flight, and landing. A Description of Important Muscles in Ski Jumping The in-run and in-flight stages of ski jumping heavily rely on prime mover muscles of the athlete. From anatomy and kinesiology, the muscles that make movement possible are known as prime movers. In ski jumping, glutes and quads muscles are the prime movers. As opposed to other vertical jumps that involves the hands being held at the sides, ski jumping does not involve he calves in its movements. This is in view of the fact that the feet of the ski jumper are required to stay flexed to keep the ski tips up and allow the jumper to maintain an aerodynamic position. The flight stage also makes use of the group of muscles known as stabilizers. Stabilizers serve the ski jumper by ensuring that he maintains a body posture during the flight stage of the movement. This group of muscles achieve this role through their isometric contraction. The muscles making up the abdominal role, rectus abdominus in addition to the internal and external obliques are the important stabilizers that see the ski jumper keep a trunk posture during the flight stage of his engagement. Stabilizers work in pairs or in groups around a joint or a set of joints. Ski jumping also employs antagonistic muscles in its movements—those muscles that tend to oppose the work of the prime movers. In actual sense, antagonists tend to resist movement. In ski jumping and other high-speed sports, these muscles play the important role of protecting the joints from injury through making the movement slow as the ski jumper nears the end of the range. In ski jumping, antagonist muscles are therefore relevant at the landing phase of the sport. In this regard, the muscle group known as hamstrings act as the antagonists to the quadriceps. Figure four: an illustration with some of the important muscles in ski jumping among them rectus abdominus, quadriceps, and hamstrings Figure five: internal and external oblique, and rectus abdominus and their particular relevancies. In light of the above, it is safe to say that ski jumping is a highly technical sporting event that requires an intricate balance of forces between the body and equipments. Literally speaking, ski jumping is like launching a human projectile the furthest possible distance. As such, in ski jumping gravitational potential energy is converted to energy in motion—kinetic. the ‘human projectile’ aspect of ski jumping makes it of particular importance in biomechanics. Work Cited Muller, W. "The physics of ski jumping." 2009. 17 March 2012 . Read More