Review of the Biomechanics of a Ski Jump - Research Paper Example

Review of the biomechanics of a ski jump Introduction Ski jumping is a sport that human quest for the desire to fly from the top of a mountain or slope. This sport started in the 1840s with a 30 m steep slope. This is a delicate sport in which a jump is completed for approximately 10 seconds. In order for one to do a successfully jump, the ski jumpers must rely on their sense of posture and flight. Performances in ski jumping can be greatly affected by external factors like jump tower conditions, temperature and wind. Ski jumping is a competitive sport that needs sophisticated infrastructure. Ski jumping puts a lot of pressure on the athlete’s ability to control the moment and pressure. Most of the ski jumpers are extremely underweight .The ski jumping movement can be divided in six phases. This includes the in run, take –off, early flight, stable flight, landing preparation and landing phase. Each of these phases has a specific function that contributes enhancing performance through maximizing both the length of the jump and the technical quality (Tani 56). Biochemical research in ski jumping is extensively covers three areas. This includes the field studies on hill jumps and mountains, computer simulations of the flight phase and studies of simulation jumps. The two objectives of field studies of hill jumps involve the description of motion and purpose of the parameters that relate to performance. The computation of flight phase used is kinematic, kinetic and electromyographic methods. The simulation jumps that are employed in technique specific training are used for performance diagnostics. There are different conditions between the simulation jumps and hill jumps performance in ski jumping can not only be determined by the motor abilities but by a major extent of aerodynamic features of the equipment by a low body weight. This paper seeks to critically analyze the biomechanics of ski jumping. The above figure shows the competent balance of a ski jumper. Phases in ski jumping During the in run phase, the athletes tries to maximize acceleration and simultaneously minimizing both the friction between the skis and the snow. He or she does this in the aerodynamic drag in order to obtain a maximum in run speed that greatly influences the jump depth. There is limited information between the friction that exists between the snow and skis. The reduction of aerodynamic drag in the in- run phase is primarily as a result of the athlete’s posture and the design of the dress code (Shao-Ming 67). The curved form in the in-run prior to a ramp, the ski athlete has to counteract the centrifugal force that is acting on him. This phase is immediately followed by the athlete’s acceleration in the perpendicular dimension to ramp due to the muscular exerted. The take off phase requires an extension of the hip and knee joints that helps in producing a negative aerodynamics effects. A three dimensional camera using the tilting method is sued to analyze ski jumps. In most athletic events, the stretch shorten cycle is used. This phase examines two dimensional motions of the subjects, the jumper’s body and the experiment that is divided in four sections. This includes the upper body, thigh, lower leg and ski. The change of the knee angle is used to determine the existence of a stretch shorten cycle during the take of motion. Maximizing the flight is regarded as the general objective of all other phase in ski jumping. In the flight phase, jumpers can increase their distant jumped can increase their ski angle and leg angle while decrease the trunk. The jumpers should maintain approximately 40 degrees of the angle of ski and the direction of the trunk. This should be applied in the second part of the flight phase. This can be achieved by holding a flight position with a small leg and direction of flight angle. The technique that jumpers use during this phase is known as the V style. The total duration of the flight trajectory for ski jumping is very short (about 4 seconds). Therefore jumpers need to optimize the ski and body position quickly. In the landing phase, the aerodynamic drag can be maximized and the lift minimized for a jumper to achieve safe and artistic landing (Pulli 30). In the landing phase a jumpers shock absorbing joints i.e. the ankles, hips and ankles come in handy. The landing should be soft and silent to enable the jumper to concentrate on the perfect balance while maintaining the position. The distance of the centre of mass to the landing is also known as DF is a skill that jumpers use when slowing their speed at the lower levels of the hills. Biomechanics methodology in ski jumping Kinematics Kinematics has been the most habitually used technique in ski jumping studies irrespective of all the mechanical challenges. This kinetic method has been developed for both hill jumps and jumps associated with dry lands. Because of the kinetic method being non-reactive, it can be utilized in both competition and for training purposes. The mechanical approaches are usually diverse. The use of two- dimensional kinematics with cameras attached to them is initiated in the analysis of take-off actions in sagittal airplanes. The easiest approach of studying the sagittal airplane movements in ski-jumping over large areas is recording with coordinated cameras situated perpendicular to flight paths. Initially, the single records are scrutinized separately and then transmitted into universal synchronized systems using explicit mathematical explanations. The kinetic approach has been used for a long time and proven consistent. More advanced approaches of using kinetic methods are using tilted, zoomed and panned cameras to establish 3D coefficients of body landmarks. The merit of these methods is the permutation of covering a large spatial range up to 50 m along with a high spatial resolution of around 4-10 mm/pixel of 3 dimensional coordinates. A major drawback of this method is the reconstruction of the body landmark points by using the zoomed, skewed and berated cameras. Dynamics and aerodynamics The methodology of measuring dynamics when ski-jumping is used in both hill jumps and simulated jumps. Data in relation to ground reaction forces during simulated jumps can be acquired through force plates found in a laboratory. These methods are used in the routine diagnostics to study basic and applied characteristics of power, conditioning and technique. The most habitually used technique in measuring reaction forces in hill jumps uses force plates fitted in the take-off tables (Campbell 320). Some of the plates installed only measure the forces vertically while other plates measure each of the tracks separately in three or two directions. This gives the possibility to establish magnitudes of force mechanism. This method is advantageous because it provides researchers the chance of collecting forceful data without prying with the jumper’s actions in any way. The limitation is that only the final part of the in-run and the take-off can be calculated. Aerodynamic forces acting on the ski jumping activity cannot be measured directly when hill jumps are taking place. Electromyography Electromyography is not widely used in ski- jumping biomechanics. During hill jumps, individuals are usually required to carry storage devices during the whole exercise. At times, difficulties arise during the flight and the in-run phases which tend to restrict the attainment of information in training jumps. Muscle activation models are studied carefully during simulated jumps in the laboratory. Electromyography’s contribution is limited to essential descriptions of muscle activities. It is also limited to synchronization patterns during the jumping activities. In conclusion, performances in ski jumping can be greatly affected by external factors like jump tower conditions, temperature and wind. Ski jumping is a competitive sport that needs sophisticated infrastructure. There are different conditions between the simulation jumps and hill jumps performance in ski jumping can not only be determined by the motor abilities but by a major extent of aerodynamic features of the equipment by a low body weight. All the phases are important for a ski jumper to enable skill development. The biomechanics methodology in ski jumping include: Kinematics, Electromyography and Dynamics and aerodynamics are important factors to facilitate effective skiing. Work cited Tani, I. & M. (1971). Flight mechanical investigation of ski jumping. In K. Kinoshita (Ed.), Scientific study of skiing in Japan (pp. 35- 52). Tokyo:Hitachi. Campbell, K. R. (1990). Biomechanics of ski jumping. In M. J. Casey (Ed.), Winter Sports (pp. 315-323). Philadelphia: F. A. David. Pulli, M. (1989). Biomechanics of ski jumping. Ski Jumping1-46. Rernizov, L. P. (1984). Shao-Ming, C. (1994). Biomechanics of optimal flight in ski jumping. Journal of Biomechanics, A kinematic analysis of the V-style Thunder Bay, ON. 167- 17 1. 167- 17 1. Vaverka, F., (1994). The System of Kinematic Analysis of Ski-jumping. Biomechanics in Sports Read More