The present study investigated the relation between the level of progress in kendo performance and the ability of modulation to stretch reflex activities including the long latency components. We used motor tasks that required positioning a handlebar, held in the hand, over two different target positions in response to a rapid muscle stretch in the wrist flexor. The target positions were a position 30°C to the extension side (extension task) and a position 30°C to the flexion side (flexion task)of the neutral wrist position. The records of motor tasks were the time taken to stop the handlebar on the target positions from stretch onset (time to stop). The short and long latency activities (M1 and M2 components) of stretch reflexes were measured by averaging the rectified electromyogram (EMG) s recorded with surface electrodes over the wrist flexor. The subjects were 21 healthy university students (mean 21.2 years), comprising 7 kendo players of a high skill level (high skill group),7 kendo players of a middle skill level (middle skill group) and 7 inexperienced persons (inexperienced group). The main results were as follows: 1) The activities of M1 and M2 components in the extension task decreased for all subjects. 2) The activities of M2 components in the flexion task increased for all subjects. 3) The degree of decreased or increased reflex activities in the high skill group, middle skill group and inexperienced group were larger in that order. 4) The time to stop in the high skill group, middle skill group and inexperienced group were reduced in that order too. In this experiment, the tension produced by the stretch reflex activities of the wrist flexor should obstruct the voluntary movements when the target position is the extension side of the wrist joint. Contrary to this, when the target position is the flexion side, the increase of the reflex tension should help to perform the voluntary movements. Therefore, the modulation of stretch reflex activities including the long latency components is rational for motor tasks in the study. Moreover, the ability of modulation to stretch reflex activities increased according to the progress in kendo skill. Based on these findings, we claim that the ability of modulation to stretch reflex activities with the appropriate motor control of the forearm is closely connected with good performances in kendo.
Since a Japanese-style bow is very complicated in both shape and structure, torques in horizontal and sagittal planes regarding grip must be applied to hit the target. This study biomechanically investigated the relationship between left forearm muscular activities and torques in horizontal (called the “NEJIRI” technique) and sagittal planes (called the “UWAOSHI” technique)regarding grip.Surface EMGs of four muscles (extensor carpi radialis longus, extensor digitorum, extensor carpi ulnaris, flexor carpi ulnaris) were collected from ten male subjects shooting arrows. The habit of the motion of drawing the bows that is called “BIKU” was measured incidentally from the experiment. As a result of statistics analysis, extensor digitorum and extensor carpi ulnaris muscles had positive relationships to the torque in the horizontal plane (“NEJIRI” technique). On the other hand, extensor carpi ulnaris and flexor carpi ulnaris muscles had positive relationships to the torque in the sagittal plane (“UWAOSHI” technique). It is suggested that extensor carpi ulnaris is complicatedly controlled to accomplish the operation of “TENOUCHI”, the shooting technique, in KYUDO.
This study was designed to investigate the physiological effects of certain judo moves as measured by changes in the rate of urinary ion excretion after three typical judo moves (nagewaza, katamewaza and uchikomi). The subjects were six male university judo players. The subjects performed a typical 10-minute moves on separate days. The results are summarized as follows: 1) All three moves brought about a reduction in urinary sodium ion (Na+) excretion but had no natriuretic effects on the subjects. 2) All three moves brought about a reduction in urinary chloride ion (Cl-) excretion in the subjects. 3) Urinary flow and Cl- excretion rates were closely correlated with the Na+ excretion rate (r=0.920 and r=0.972 both p< 0.001). These results indicate that the subjects performed the 10-minute series of judo moves with lower lactic acid oxygen debt than normally seen in anaerobic exercise.
This study investigated several aspects of present IJF (International Judo Federation) Refereeing Rules including problems and future goals of its refereeing methods in Japan. A survey of 522 people targeting the contestants (university students and adults) and persons concerned in several past Judo events in Japan was conducted and analyzed as three statistic categories; the whole, by age and those with international competition experience. The results suggest the following: 1. A more impartial and fairer system of judging is demanded. 2. Referees' understanding of the Refereeing Rules needs to be unified. 3. The age group of 27 years or older has negative concerns about adopting new gestures and referee rules. 4. The right understanding of the Refereeing Rules and moral education of referees are required in the early stages when they are on the active list. 5. When appreciating “Ippon”, referees are negative to the present method of “waza” counting. 6. The present method of “waza” counting is considered to be illogical because it does not count points other than “waza-ari”. 7. In terms of counting “waza” points, more than half of them consider those two points as an upgrade. 8. The estimation of technical points and the application of penalty points are important issues to be considered synthetically.
The Japan Karate-do Federation (JKF) decided to implement Doping Control (here in after DC), following the regulations and methods for anti-doping of the International Olympic Committee and the World Karate-do Federation. The JKF made its own manual for DC, educating staff and enlightening players and coaches, and put it into effect for the first time at the 3rd World Woman's Karate championship held in Fukuoka on the 11th July 1992. In July 1995, Tokyo became officially recognized as the permanent venue for the Lady's International Karate-do championship. The DC panel and sample-taking team members are mainly drawn from the JKF Medical Science Committee who conducts anti-doping education focusing on members of the JKF national team. No player had refused drug testing until the championship held on Nov.15 2001. Also, their 53 samples have yet to show any positive reaction for punishment. Although detailed regulations for random testing are set out in the JKF and DC manual no such testing has been conducted as yet. After sample taking, some parts were in compliance with the manual, but they were amended each time. A significant number of problems at the testing station both procedural and practical still need to be addressed, e. g. insufficient space, inadequate toilet facilities and a lack of securable premises, as well as a lockable refrigerator. Since Med. Science Committee members do not accompany teams going to tournaments overseas, coaches are now provided with the medicines for each of the subjective and objective symptoms (corresponding to DC) that may be made available to team members when deemed necessary.