The biological mechanics demonstration and the practical employment of two-jump type take-off in long jump

Introduction

This paper is a review of the relevant literature in the biomechanics of the long jump take off and our work in this area[1,2], which includes the dynamics and kinematics of 36 elite athletes. It also contains a discussion of the basic principles of the biomechanics of the long jump and the characteristics of the 3 types of take-off technical models,
which are the "brake type", "run type" and "two-jump type". It extends and builds upon the concept of the run-up and take-off technique in the long jump, first described theoretically by Arabin [1]. The paper defines the "two-jump type" take-off technique for the first time and discusses it in theory and practice.

Methods

Through a biomechanical analysis of the differences of jumping techniques of the elite long-jump athletes, we discovered that athletes adopt different technical models of taking off actions. At the same time, we analyzed the videotapes of the first 3 long jump athletes in the Sydney 2000 Olympic Games (Ivan Pedroso 8.55m, Jai Taurima 8.49m, Roman Schurenko 8.31m). It was discovered that the techniques of the 3 athletes in the run-ups coincide with the characteristic of the 3 technical model types for the take off in the long jump.
Based on the above theories we have a developed a computer-based model of long jump as a training aid. This includes a parameter table for different levels of long-jump athletes that reflects the relation between the angle of taking off and the speed of taking off, with visual reference and target values for improvement of the take-off technique. In order to support this new technical theoretical foundation, we have performed a practical verification test. We selected two groups of experienced athletes, 17 athletes altogether, and performed a contrast study. The experimental results showed that the record of the group which adopted the "two-jump type" technical model improved 7%, while the record of the control group improved only 2.5%. The experiment has fully proved the feasibility and the practicability of this technical theory.

Conclusions

1. Through the analysis based on the computer-based technical teaching model it was discovered that the take-off speed and angle do not show a linear relationship. Reasonable take-off angle range is 60-70 degrees and reasonable running angle range is 19-26 degrees; Run-up speed loss should be between 8%-15%.
2. The partition of run-up and take-off should start from the penultimate step during which the leg starts to land, and this proved that there is really such technique as "two jump type". The adoption of this technical model can improve the take-off rhythm, increase the feet angle and achieve a good take off effect.
3. During the athlete’s final run-up in the long jump, the leg joints reduced range is 8-28 degrees, and this depends on the different technical model adopted.

References

[1]. Arabin (1994) Journal of Haerbin Institute of Physical Education, 8, 25-28.
[2]. Yang J. (1992) Track and Field, 6, 31-33.