THE STUDIES ON AEROBIC WORK CAPACITIES OF PREPARATORY SCHOOL CHILDREN (III) / 体力科学

ABSTRACT

In order to find out the criteria for the determination of maximal oxygen uptakes of very young children, five boys and five girls, aged four or five years, served as the subjects. They ran on the horizontal treadmill once a day for the constant three minutes on different days. The velocity was increased from the first 100m/min by 20m/min till the last where they could endure no longer for the three minutes. As the consequence, the velocities attained were 100m/min, 120m/min, 140m/min, 160m/min, 180m/min and 200m/min for boys and 100m/min, 120m/min, 140m/min, 160m/min and 180m/min for girls.<BR>The expired airs were collected at rest and whole through the treadmill running.<BR>Heart rates were also continuously registered not only at rest but also during the treadmill running.<BR>The following results were obtained<BR>1) At the velocities of 100m/min, 120m/min and 140m/min apparent steady states of heart rates and Vo<SUB>2</SUB> were established within the three miuntes both for boys and girls.<BR>But boys showed lower heart rates and higher Vo<SUB>2</SUB> during the steady states at a given velocity than girls did.<BR>2) At the last velocity of 200m/min Vo<SUB>2</SUB>max were attained 30 seconds after the start of running for boys and also at the last of 180m/min girls reached Vo<SUB>2</SUB>max 60 seconds after the beginning.<BR>It was, therefore, confirmed that if the work intensity was sufficiently high, Vo<SUB>2</SUB> max could be reached at the latest between 30 and 60 seconds after the start of work for young children.<BR>3) At the one step lower velocity than the last, namely, 180m/min for boys and 160m/min for girls, the plateaus of Vo<SUB>2</SUB>max were found for the last minute.<BR>4) The heart rates simultaneously observed with Vo<SUB>2</SUB>max ranged from 202.4 to 206.4 bpm and also RQ were all above the unit. Accordingly these values could be regarded as the most important critieria for the evaluation of aerobic work capacity of young children.<BR>5) When the velocity was high, the respiratory frequency sharply rises immediately after the start of running. For the first thirty seconds the breath rates reached 60 to 90/min.<BR>6) If the duration of the running on the horizontal treadmill are constantly fixed three minutes, the upper limit of the velocity where the safe aerobic steady state can be established is 140m/min both for boys and girls.