RESUMO
The purpose of this study was to analyze morphological and functional changes in the left ventricular muscle mass and vessel diameters of the arteries in young competitive athletes of various sports and evaluate the correlation between the heart and arterial vessel under the training environment in this latter half of the growth period. The subjects were 51 male college student athletes (mean age, 19.6±0.4 years) of 6 competitive sports (archery, weight lifting, swimming, short-distance races, middle-distance races, and long-distance races) . The diameters of the right and left common carotid arteries, right and left radial arteries, right and left foot dorsal arteries, and the aorta and the left ventricular muscle mass (LVM) were measured by Doppler echocardiography. To minimize the influences of the physique and body weight associated with growth and sport types, all data obtained by measurement were corrected by body surface area. The sum of the diameters of all the above arteries (total arterial diameter : TAD) was obtained to evaluate its correlation with the left ventricular muscle mass. The diameter of the foot dorsal artery was significantly higher in the long-distance runners than in the sprinters (P<0.05) . The diameter of the radial artery according to the 6 types of sport was the highest for weight lifting, followed in order by archery, longdistance races, middle-distance races, swimming, and short-distance races, showing a significant difference between weight lifting and short-distance races (P<0.05 ) . TAD was high for generalized endurance sports and correlated with the left ventricular muscle mass (r=0.893) . Thus, the arterial diameters significantly differed among competitive sports and were particularly increased for endurance exercise. The diameters of the local arteries used for local exercise were also increased. When TAD as a new parameter and its ratio per body surface area were calculated, there was a high correlation between the heart (left ventricular muscle mass) and the arterial diameter. These results suggest that exercise adaptation can he evaluated in the arterial system in svstemic circulation as well as the nervous and muscular systems.
RESUMO
The purpose of this study was to analyze the relationship between activity pattern and temporal changes in the oxygen dynamics of human femoral medial vastus muscles. Oxygen dynamics were evaluated from the surface of the body by near-infrared spectroscopy (NIRS) . Arterial occlusion tests were performed in the femoral region at a cuff pressure of 300 mmHg. Exercise type and speed were controlled by CYBEX 6000. The exercise types examined were concentric contraction (CON) and eccentric contraction (ECC) . The 3 angular velocities of 90, 120 and 180 degrees were used as the exercise speeds. Exercise was performed continuously 60 times at maximum effort. The subjects were 7 healthy males with a mean age of 19.6±0.5 years. A transient decrease in oxygen concentration was observed during circulatory occlusion ; and rapid hyperemia occurred immediately after the removal of pressure. Oxygen concentration peaked above the control level and then returned to the initial level. In the CON exercise, the initial decrease in oxygen concentration was the largest at CON 90, and a gradual increase in oxygen concentration was clearly observed during exercise. In the recovery stage, after exercise at CON 90, 120 and 180, oxygen concentration exceeded the control level before exercise, then peaked and returned to the initial level. In the ECC exercise, an initial decrease in oxygen concentration was similar to that in the CON exercise, but a gradual increase in oxygen concentration was not observed during the exercise ; nor did oxygen concentration exceed the control level in the recovery stage after the exercise.<BR>These results indicate that an increase in oxygen level after the removal of arterial occlusion, during and after the CON exercise was much higher than the control level before the exercise, sug-gesting the involvement of reactive hyperemia and exercise hyperemia.
RESUMO
Purpose: The purpose of this study was to examine the relationship among helmet surface temperature (Thl), head top temperature (Thd) and tympanic temperature (Tty) during American football practice in summer. Methods : The subjects were collegiate American football players. Temperatures were measured in August in 1993 and 1994. Thl, Thd and Tty were measured by infrared tympanic thermometers. Environmental temperatures that were measured were dry-bulb temperature (Td), wet-bulb temperature (Tw), globe temperature (GT) and wet-bulb globe temperature (WBGT) . Results: Significant correlations were observed among all measured temperatures (P<0.0001) . High coefficients of correlation were observed among Thl, Thd and GT. The highest relationships were observed between Thl and Thd (r=.727), and between Tty and Td (r=.766) . The coefficient of correlation between Tty and Thl was higher than that between Tty and Thd. Heat stress of the whole body (F1; heat stress factor: Tty, Td, Tw and WBGT, proportion=71.4%) and head environment factor (F2 ; helmet factor : Thl, Thd and GT, proportion=14.3%) were chosen in factor analysis. A close relationship was observed between both factors (r=.773) . Both GT and Thl showed a high correlation with Thd, which suggests the influence of radiant heat through a helmet on the whole body. Conclusion : The temperature in a helmet is a micro environment temperature surrounding the head. Accordingly, the heat load is reduced by taking the helmet off frequently during football practice.
RESUMO
The kinesiological characteristics of press, snatch and jerk, the physical strength and the records of the weight-lifters of the first rank in Japan were chronologically investigated and evaluated by taking into consideration the records of weight-lifting in the international athletic meeting. The summary of the results obtained is as follows:<BR>1) In press of weight-lifting the record got better chronologically, but in movement analysis the remarkable improvement was not observed.<BR>2) In the beginning of press the velocity change rather increased chronologically. Taking into consideration of the annual change of physical strength and weight-lifting record, there could exist a technical change in press, e.g. they came to have the increased tendency to get supplementary strength in the beginning of press by the under extremities.<BR>3) The hypothesis that it will be desirable to have higher speed at S.P. point in proportion to increased weight, does not always hold true in snatch.<BR>4) At 6 events the distance of jumping back varied from 15 to 25 cm in the almost all subjects.<BR>5) In jerk the acceleration of movement at each point deviated quite a lot, namely, there was found no definite tendency of the acceleration.<BR>6) Trunk and knee angles slightly increased year by year, which could be considered to be as the result of the technical improvement.<BR>7) The A.H.J. of trunk angle at S.P. point during clean movement was the biggest in jerk, next in press and then least in snatch, and the velocity at S.P. point was in the reverse order of the relation of that angle.<BR>8) In muscle strength, pressure of bearing up, side-step, Harvard Step Test, vertical jump, flexibility and Typus Index, a characteristic change could not be observed.<BR>9) In the total record considerable annual increase was observed and smaller difference among the athletes was found.<BR>10) In press, jerk and snatch each record was in the following order : 1. press, 2. jerk and 3. snatch. Among those 3 items the increasing ratio of press was the biggest and the others were smaller than that and almost same each other.<BR>11) Including the records of the international events the lifting marks and the records got pretty better chronologically, and the difference between domestic and foreign records became smaller which meant that the domestic records had come close to the international level.<BR>12) The each annual increasing ratio of domestic record of those 3 items was slightly larger than previous one, but in foreign records the annual increasing ratio of snatch was observed to be smaller, compared with those of the other two items.<BR>13) The increasing ratio of the lifting weight per 1 kg body weight was about 104% at minimum and about 113% at maximum, compared with that of 1960's record, and it became larger as the weight class became heavier.
RESUMO
In grip strength a subject being ordered to show one-third, one-second and twothird of his own maximum value after checking his maximum, the value he shows is not always the same as the ordered value. The Discrepancy Index was determined by the grade of the difference between the ordered value mentioned above and the value showed actually.<BR>For 2117 subjects composed of both sexes our experiment was performed.<BR>1) The possibility of training effect for one-third and two-third of their own maximum value existed but little for one-second.<BR>2) Up to 16 years of age the training effect increased with their physical development, but after 17 years remarkable change of their grading ability was not found.<BR>3) There existed no relation between the experimental results of one-third value and two-third, between the left hands and the right, and between the Discrepancy Index of pre-training and post-training.<BR>4) The larger maximum value of grip strength became, the smaller the Discrepancy Index was. Sometimes in the individuals who have larger maximum value, the more training effect was recognized.<BR>5) The champions of weight-lifting, Kendo and volleyball showed better results than those of the control groups.