THE STUDY ON AEROBIC WORK CAPACITIES IN URBAN AND RURAL ABOLESCENTS / 体力科学

ABSTRACT

According to the past results of Sport Test held in TOCHIGI Prefecture in 1968, it was certainly found that the endurance run test showed the most characteristic regional trend that adolescents born and reared in mountaineous farm villages, which topographically lie from mountain to plain, obtained significantly better performance than those in commercial and residential streets. The main objectives of the present investigation were to know how much difference, if any, is found concerning endurance capacities between the both adolescents and the study was, therefore, designed in the sphere of physical resources of energy to measure the aerobic work capacities of PWC<SUB>170</SUB> and Vo<SUB>2</SUB> max., and it was assumed that commercial streets represenetd urban districts and on the other hand mountaineous farm villages also represented rural districts. The total number of subjects, aged from 9 to 17 years, who performed the PWC<SUB>170</SUB> test of submaximal work load as preliminary one, were 732; 159 in male and 157 in female in urban, and 218 in male and 198 in female in rural districts. But the subjects to be tested in Vo<SUB>2</SUB> max. of maximal work load were further chosen at random from those who received the PWC<SUB>170</SUB> test, and the number of them were 559 in all. The apparatus for the determinations of PWC<SUB>170</SUB> and Vo<SUB>2</SUB> max. was MONARK bicycle ergometer. The three points-four minute method was used in the PWC<SUB>170</SUB>test and the two-minute stepwise method was adopted for measurement of Vo2 max. The pedalling rate was 50 rpm in the both tests. Every step of work load was increased by 150kpm/min. Concomitantly skinfold thicknesses in the four points of upper arm, scapula, wast, and umbilicus were also measured.<BR>The following results were obtained<BR>1) Urban adolescents had significantly thicker subcutaneous fats than rural ones.<BR>2) No differences were found in PWC<SUB>170</SUB> (kpm) in all the ages between urban and rural adolescents for male, but rural adolescents were significantly superior to urban ones after the age of 12 years in PWC<SUB>170</SUB> (kpm/kg) . For female urban adolescents were rather better than rural ones before the 11 years, but on the contrary rural adolescents were significantly higher in PWC<SUB>170</SUB> (kpm/kg)<BR>3) The regional differences that rural adolescents were superior to urban ones in aerobic work capacities were recognized earlier in age for PWC<SUB>170</SUB> (kpm/kg) than for Vo<SUB>2</SUB>max. (ml/kg), and further appeared in younger ages for female than did for male.<BR>4) In the regression equation y=ax+b, in which x was assumed to express body weight (kg) and y mean PWC<SUB>170</SUB> (kpm) or Vo<SUB>2</SUB> max. (1), and the standard deviation from y, &delta;y, was also calculated, the characteristic regional trend was found in urban and rural districts. Then it could be considered that a was the increase rate of aerodic work capacities to body height and &delta;y was the interpersonal variation. In the case of Vo<SUB>2</SUB> max. (1) for boys, the higher increase rates were consistently found in rural districts and the smaller variations were also identified. It is apparent that this is partly due to the higher occupation of the activating tissues in body weight increaserate and partly due to their better functioning.<BR>5) According to the allometrical expressions concerning aerobic work capacities, y=b×h<SUP>a</SUP>, obtained by the same mathematical procedure as used by Asmussen, PWC<SUB>170</SUB> (kpm) for boys had the same body heights in the two critical points of urban and rural districts, and up to these body heights a was considerably higher in rural boys but almost same α were indicated after the points. As for Vo<SUB>2</SUB> max. (1), the body heights in the critical points differed in urban and rural districts, that is, the body height in rural boys was about 10cm higher than in urban ones.