1994 年 26 巻 3 号 p. 31-40
The purpose of this study was to clarify the effect of NEJIRI-technique in KYUDO to mechanical characteristic of Japanese bows. Torsion in restitution of subjects, torsion-bend relation and energy transfer of bows were measured by experiment and mechanical model was constructed. Then, NEJIRItechnique in KYUDO using computer simulation was analyzed. The results were as follows:
(1) Torsion in restitution of subjects had three types. The first one was rapid reduction type (type-A).
The second one was slow reducion type (type-B). The third one was the type that has a peak in the latter half (type-C).
(2) In regard to Energy transfer efficiency, type-A of subjects was 54.9±1.0 %, type-B was 56.4±1.1 %, type-C was 58.3±0.8 %. Each value were significantly difference (p<0.05 p<0.001). It is possible to compare NEJIRI-technique level searching torsion types in restitution of subjects.
(3) In the case of adding torque to the bow grip, the rate of bend-strain toward no adding torque didn't change in drawing range from 90 cm to 50 cm. The other side, in drawing range from 40 cm to 20cm the rate changed. It appeared that bend-strain of Japanese bows has non-linear feature.
(4) The result of computer simulation using mechanical model including non-linear parameter was near value of energy transfer and arrow's velocity by experiment.
(5) Type-C that has a peak in the latter half was good NEJIRI-technique for increasing mechanical efficiency of Japanese bows. This was mechanical significance of NEJIRI-technique in KYUDO.