1996 年 29 巻 2 号 p. 47-59
The purpose of this study was to determine specifically what effect Judo has on the structure ofthe left ventricle, in terms of maximal oxygen uptake (VO2max) and anaerobic threshold, in relation to weight of the athlete. This study used 17 Japan female Judo athletes who were part of the delegation to the Olympic Games, and national elite Judo athletes appointed by the All Japan Judo committee who compete in domestic Judo championships. The structure of the left ventricle was measured by echocardiography using the M-mode method. VO2 max was measured in a breath by breath method with a cycle ergometer and the indicated value was converted to a treadmill value. The subjects were divided into three groups : in the light class were six athletes (48.0-56.0kg), in the middle class were five athletes (56.0-66.0kg) and in the heavy class were six athletes (above 66.0kg). The following results were obtained :
In terms of physical characteristics, the average height of the members of the light, middle, and heavy classes were 156.3 cm, 159.5 cm, and 165.9 cm respectively ; the average weight were 54.0kg, 58.5kg, and 71.4kg, respectively. The body mass index (BMI) were 22.0, 23.0, and 26.1 in the three groups. However, the percent of body fat were 16.3%, 18.6%, and 20.9%, and it is thought that the BMI of the heavy class is not responsible for the increase in fat volume, but due to lean body mass.
In the structure of left ventricle, the interventricular septum thickness (IVST) of the three groups was 7-8mm, and the left ventricular posterior wall thickness (LVPWT) was nearly 7mm. These values agreed with those in other female athletes. Female Judo athletes who compete with relatively intense muscle contraction did not indicate any myocardial hypertrophy. The left ventricular end-diastolic dimension (Dd) in the light, middle and heavy classes were 52.8 mm, 52.4 mm, and 53.9 mm respectively. It is considered that these values were higher in comparison with other elite athletes (47-55 mm). Therefore,the left ventricular dimensions of female Judo athletes who train with volume load is large. Without regard to weight, the Dd and aortic dimensions are bigger. It was suggested that this has a strong effect on the vascular system because it has been pointed out that increasing Dd produces an increase in the aorta which consists of collagen fibril.
VO2 max per body weight in the light, middle, and heavy classes were 45.9 ml/kg.min-1, 43.7 ml/kg.min-1, and 43.1 ml/kg.min-1, respectively. The values which were converted to treadmill values were 52-55 ml/kg .min-1.This value is almost the same compared to other female sports athletes of 50-55ml/kg.min-1 suggesting that Judo athletes have a good systemic aerobic capacity. Averaged values of the ventilatory threshold in the light, middle, and heavy classes were 62.3%, 60.5%, and 60.3% respectively, and these were the same as other elite athletes. The Dd of the subject, Sugawara Noriko, light class, who participated in the 1996 Atlanta Olympic Games was 53.6 mm, her VO2max (converted) was 63 ml/kg.min-1, and her anaerobic threshold was 72% of VO2max. The Dd of the subject, Tanabe yoko, heavy class, was 56.7 mm, her VO2max (converted) was 50 ml/kg.min-1, and her anaerobic threshold was 74% of VO2max. These results which are equal to those of long distance runners are due to daily aerobic training, and suggest that athletes who take part in international competition have good, basic physical fitness as well as technique as elite sport athletes.