The purpose of this study was to investigate the characteristics of physical fitness in college male kendo competitors(KC)by comparing the composing factors of physical fitness between 136 KC and 61 general college male students of a similar age(GS). A total of 42 tests representing 5 physical fitness domains was examined on the above mentioned subjects. Factor analytic technique was applied to each correlation matrix consisted of variable groups of each physical fitness domain. The main findings can be summarized as follows: 1)Values of body bulk variables such as body weight, upper arm girth and lower leg girth in KC group were significantly higher than those in GS group.Among the 3 physique factors interpreted, a significant difference in body bulk factor was found between KC and GS groups, but not in body fat and body linearity factors. The KC group was inferred to have more developed muscle. 2)Static strength values such as grip strength, back strength, leg strength, shoulder arm strength, and standing long jump in KC group were significantly higher than those in GS group.Static strength and dynamic strength factors in strength domain were interpreted and the former's value was significantly higher in KC group than in GS group.The KC group was inferred to be superior in static strength of the limbs and trunk, and in muscular power of lower limbs. 3)Values of agility tests such as side?steps, total body reaction time and fingertip in KC group were significantly superior to those in GS group.Among the 3 nervous function factors interpreted, significant differences in agility factors of limbs and total body were found between KC and GS groups, but not in balance factor. The KC group was inferred to be superior in agility-of limbs and total body. 4)Values of trunk and ankle flexibilities in KC group were significantly less than those in GS group.Among the 3 joint function factors interpreted, trunk and ankle flexibility factors were significantly inferior in KC group to in GS group.Therefore, the KC group was inferred to be inferior in flexibility of trunk and ankle. 5)Values of the 3 cadiovascular function factors of aerobic power, respiratory function, and anaerobic power were significantly higher in KC group as compared with GS group.Therefore, the KC group was inferred to have superior cardiovascular function.
The purpose of this study was to clear mechanical characteristics of the Japanese bow, and find the energy transfer efficiency. The exeperiments were made by five classes of bows, arrows and strings heights. The potential energy(PE)was calculated on every bows. And the kinetic energy (KE)was calculated from shooting experiment according to arrows and strings heights. Then, the energy transfer efficiency was obtained on KE/PE X 100. The results were as follows: 1, Relation between the drawing length and the drawing force shows a inverted S curve. This characteristic is constant regardless of the bow's strength and strings height. 2, The potential energy is increased by the drawing length. The general tendency that the strong bow has high potential energy was evident. 3, The minimum of the energy transfer efficiency lies on 15cm of the strings height in the experiment according to five classes strings height. 4, In this study, the energy transfer efficiency is increased until 29g of the mass of arrow. And more than that, the energy transfer efficiency was decreased. It seems that there is a matching point of bow and arrow.
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.
The purpose of this paper was to examine correlations between efficiency of energy transfer and several indices obtained from strain gauges equipped with on a bow, and found a criterion to evaluate a shooter's technique with regard to the left hand. We analysed twisting moment and bending strain of a bow during a bow's restoration. The conclusions were as follows: 1. The efficiency is significantly correlated with values of twisting moment of a bow in the latter part of the bow's restoration sequence, but not significantly correlated with values in the former part. 2. The efficiency is significantly correlated with values of twisting moment integrated by time (P<.01), and with time when the maximum values of the moment is obtained (P<.05). However, it is not significantly correlated with the maximum value itself. 3. Some spectrums of vibration of bending strain are negatively correlated with the efficiency, especially in the low frequency domain. The number of frequencies at which spectrums are positively correlated with the efficiency is obviously smaller than number of negative correlations. Vibration of twisting moment has little meanings in comparison with that of bending strain because of the magnitude of its energy. Some of these are widely known as an empirical law. Our conclusions are consistent with it. Consequently, the conditions of a shooter's technique to transform a bow's energy efficiently are regarded as follows: * Twisting moment integrated by time is large, and the maximum values of the moment is obtained in the latter part of the bow's restoration. * Vibration of a bow's bend in low frequency (especially, about 100Hz or 200Hz) is small.