The Biomechanical Study Of The Technical Principle Of Push-off With Clap Skates On The Ice Curve

In the international world of speed skating, the use of Clap skates has ushered a new era. The fact that all of the world records before 18th Olympic Winter Games were beaked is the best evidence. Although high altitude (the Salt Lake city--1 227m) and the indoor ice rink provide the external conditions for the excellent result of the competition, the benefit of Clap skates should not be doubted. The appearance of the new type of skates has challenged the traditional skill theory of push--off on the ice and the traditional training method, which has attracted people's attention. Since the new type of skates has been introduced into China and is thought to be: compared to the traditional skates, the Clap ice-skates has prolonged the time of push--off on the ice; it has elevated the flexibility of the ankles; it has increased the width of push--off and extending of the lower limbs; it keep the blade of the skates in touch with the ice surface and the original skating direction parallel with the direction of push--off on the ice, thus it finishes the action of jigging on the ice under the conditions that the ankle is fully bent; however, there still exists the new technique: push--off towards the rear of flank or directly backwards; the bent of the knees and the movement of the ankle in the last phase is the natural action or active action; the translocation of the center of gravity is only the crosswise movement or combined with the longitudinal movement. The recognition of many important skills is still under dispute. In order to explain the mechanism of push--off on the ice of the Clap ice-skates clearly, this research applies the method of Applied Mechanics in Biomechanics. Through the technical element analysis that influences the speed of skating, this article tries to establish the right technical concept of push--off on the ice on the curve, explain the key link of the movement skills, make clear the content of the accelerating theory of the action of push--off on the ice and establish excellent athlete's parameter system of the skills of skating on the curve. Furthermore, it tries to uncover the biomechanical principle of push--off on the curve of the Clap ice-skates.The result of this research is as follows:I. The technical principle of push--off on the ice curve of the Clap ice skates.The connotation of the technical principle of push--off on the ice curve of the Clap ice skates embodies in two aspects: First, elevate the flexibility of the ankle to change the nature of the strength-exerting of the joints of the lower limbs; Second, reveal the applicable conditions of the accelerating theory of push--off on the ice of speed skating through the change of the structure of the skates. The core is to elevate the flexibility of the ankle. Concrete details are:(1) The Clap skates elevate the flexibility through the link structure of the"hinge", thus change the malpractice of traditional push--off process which mainly depends on the power of the hipbone and the knee, and thus obstruct the use of the power of ankle. The Clap skates add the exerting strength and extend the working scope of the ankle.(2) Through elevating the flexibility of the ankle, change the strength-exerting character of the joints of the lower limbs in order to accelerate the body skate speed.(3) The elevation of the flexibility of the ankle avoids the malpractice that the gravity center during the process of push--off on the ice mainly goes crosswise and is difficult to shift longitudinally and makes it possible that the gravity center actively moves forward along the direction of the tangent.II. The applicable conditions of the accelerating theory of push--off of speed skating.The research shows that the former accelerating theory is conditional when reflecting the accelerating ability of the high-level athletes. Besides, the amount of accelerating the speed to infer the accelerating mechanism of push--off should not be the only condition to accelerate the gravity center. The scope of the gravity center moving forward combined with the suitable opportunity to push--off on the ice side wards is the premise of acquiring the optimum speed. It reflects the interactive relationship between the fulcrum and the gravity center and the accelerating condition of the push--off. It is the Clap ice-skates'unique structure that makes the gravity center moving forwards possible. It embodies the reasonable application of the accelerating theory of ice-jigging of modern speed skating in the practice.III. The model characteristics of the frequency and width combination of motional supporting patternThis research, for the first time, put forwards the concept distinction between the fixed point supporting pattern and the motional supporting pattern in the study of the pace width, pace frequency, pace speed of the cyclical speed competition. Through the analysis of the relationship between the combination of frequency and width and the pace speed in the different skating speed, we find out the similarities and differences in the aspect of frequency and width combination by comparing the motional supporting pattern with the fixed point supporting pattern. The result shows: frequency combines with width in the relationship between pace frequency and pace speed in the process of speed skating from low-speed to high-speed; the motional supporting pattern observe the changing rules of the fixed point supporting pattern, fit in with the function relation of pace frequency's the concavity upward curve to pace speed, and the two entail unity; but in the relationship between the pace frequency and the pace speed, the motional supporting pattern and the fixed point supporting pattern contradict. The fixed point supporting pattern shows that the pace width increases alongside with the acceleration of the speed. (Under the condition of the maximum speed, it remains unchanged or a little reduced); the motional supporting speed shows that the pace width reduces alongside with the acceleration of the speed. The result reveals: when the supporting pattern is different (the motional supporting and fixed point supporting), in the interactive relations between pace width and pace speed, the pace width increasing with the acceleration of the speed is conditional. So we should distinct the motional supporting pattern with the fixed point supporting pattern.