ASSESSING DAILY PHYSICAL ACTIVITY IN JUNIOR HIGH SCHOOL STUDENTS USING PEDOMETER WITH ACCELEROMETER / 体力科学

The purpose of present study was to examine validity of pedometer with accelerometer (Lifecorder-EX ; LC) and to assess the daily physical activity (PA) of Japanese junior high school students by LC method. Firstly, to examine validity of LC, ten students (13.6±0.5 years old) wearing LC on their waists performed the walking and running tests. Energy expenditure was measured by the expired gas analysis method during the tests. The results showed that the activity level of LC had a high correlation with the exercise intensity (VO₂ : r=0.948, METs : r=0.931), and it was from 7 to 9 (LC7－9) in the more intense activity than running. Secondly, PA of 206 boys and 220 girls aged 12－15 years were measured using LC. Step counts and activity time of LC7－9 each were 9500－15000 counts and 10－19 minutes on weekdays, and 6500－10000 counts and 5－12 minutes on weekends. PA analyzed by MANOVA were lower on weekends than on weekdays, and decreased in proportion as grade, and that of boys were significantly higher than that of girls. Present study suggests that LC method is a good way of measuring PA for junior high school students in free-living condition.

ASSESSING DAILY PHYSICAL ACTIVITY IN ELEMENTARY SCHOOL STUDENTS USED BY ACCELEROMETER / 体力科学

The purpose of present study was to examine validity of accelerometer (Lifecorder ; LC) and to assess the free-living physical activity (PA) in Japanese elementary school students used by LC method. Firstly, to examine validity of LC, twelve children, aged 11.2±1.0 years, were measured total energy expenditure (TEE) by doubly labeled water method and resting energy expenditure (REE) by the expired gas analysis. Physical activity energy expenditure (PAEE) is calculated as 0.9 TEE minus REE. At the same time, PA was evaluated by both daily walk count (WC) and vigorous activity time (LC7-9) using LC method. PAEE per 1 kg body weight significantly correlated with WC (r=0.785, p<0.005) and LC7-9 (r=0.828, p<0.001). Secondly, 140 boys and 167 girls, aged 8-11 years were measured PA by LC method. WC and LC7-9 each were 13000-18000 counts and 16-32 minutes in week-day, and 8000-12500 counts and 8-18 minutes in week-end. PA analyzed by MANOVA were significantly higher in boys than in girls, and lower in week-end than in week-day, and decreased in proportion as grade. Present study suggests that LC method is a good measure of PA in free-living condition for elementary school students.

The effects of long-term low intensity aerobic training and the cessation of training on the serum lipid and lipoprotein concentrations in older patients / 体力科学

The effects of long-term low intensity aerobic training and detraining on serum lipid and lipoprotein concentrations were examined in 10 older patients suffering from hypertension and coronary heart disease. Training was carried out for 30 minutes 3-6 times a week for a mean of 17.1 months using a treadmill with the intensity level set at the blood lactate threshold (LT) .<BR>Following this training both LT and the serum HDL-c increased significantly (P<0.001, P<0.01, respectively) after 6 months while the TC/HDL-c ratio decreased singificantly (P<0.001) only after 1 month and stabilized at a steady favorable value throughout the remainder of the study. The serum TC, TG and LDL-c did not change significantly by the end of the training period. There was a significant negative correlation between the initial TC/ HDL-c level and the change in the TC/HDL-c level at 1 month after training (r=-0.71, P< 0.02) . Only 1 month after the detraining the HDL-c decreased significantly while the TC/HDL-c increased in comparison with the final training value (P<0.001, P<0.05, respectively) and then returned to the pre-training levels.<BR>In conclusion, these results suggest that long-term low intensity aerobic training could improve the profile of the serum lipid and lipoprotein concentrations in older patients. However, these results might depend on such factors as a low HDL-c level, a high TG level, the length of the exercise period, or the frequency per week and the age of the patient, while the cessation of such training quickly returned the profile to that of pre-training levels.

The effects of long-term mild aerobic training at lactate threshold and its cessation on blood pressure in older hypertensive patients under medication / 体力科学

After a general clinical observation period of 3 months, men and women from 66-82 yr. of age with hypertension (n=10) were studied to assess the effects of long-term mild aerobic training and detraining on their blood pressure. Ten patients agreed to take part in aerobic training using a treadmill with the intensity at the lactate threshold (LT) for 30minutes 3-6 times a week for mean 17.1±9.8 months while the time course of changes in the resting blood pressure was monitored.<BR>Following the training period the LT increased significantly by the end of the training period (P<0.001) . After 3months of training both the systolic and diastolic blood pressure decreased significantly (P<0.05, respectively) and both blood pressures stabilized at a significantly lower level throughout the remainder of the study. The mean blood pressure decreased significantly for 9 months (P<0.05) . Finally, the systolic, mean and diastolic blood pressure were found to have decreased significantly, by 9, 5, 11 mmHg, respectively by the end of the training period. (SBP and MBP: P<0.05, DBP: P<0.01, respectively) . One month after the training ended the systolic, mean and diastolic blood pressure all increased significantly (SBP and MBP: P<0.001, DBP: P<0.01, respectively) and approached the initial pre-training levels.<BR>In conclusion, the antihypertensive effect of mild aerobic training at the LT was confirmed for older patients taking antihypertensive medications. However, the cessation of such training resulted in a quick return to pre-training levels.

Effects of 9 months mild aerobic training on serum lipids and lipoprotein concentrations in older than 65 years men and women with hypertension / 体力科学

In the present study, we instiuted a long-term mild aerobic training program for older patients with hypertension and investigated its effects on serum lipids and lipoprotein concentrations. The intensity of exercise in mild aerobic training was adjusted to the lactate threshold level (LT), i, e., the level at which the blood lactate concentration began to increase nonlinearly with increasing work intensity. The training group (15 patients, 7 men and 8 women) and control group (15 patients, 7 men and 8 women) were 65-83 year-old patients with mean ages of 75.5±5.6 and 73.7±4.4 (mean±S.D), respectively, who had never exercised regularly up to that time. Treadmill training at the LT was carried out for 30min/day 3-6 times/week and continued for 9 months under the supervision of exercise physiology specialists.<BR>In the training group, LT speed significantly increased from 3.43±0.65 km/h to 3.73±0.67 km/h (9.0%) in men, and from 2.75±0.57 km/h to 3.05±0.61 km/h (11.8%) in women (both P<0.05) . HDL-c was significantly increased 9 months after training both in men (19.2%) and women (20.9%) (both P<0.05) . The TC/HDL-c ratio, an atherogenetic index, was significantly (P<0.05) decreased by training in women but not in men. The other serum lipid and lipoprotein profiles were unchanged in both men and women. In the control group, all serum lipid and lipoprotein profiles were unchanged in both men and women.<BR>The HDL-c level in the training group was higher than in the control group after 9 months in both men and women (both P<0.02) . The TC/HDL-c ratio in the training group was lower only in women (P<0.02) . There were no significant differences in other values between the training group and the control group in either men or women.<BR>These results suggest that mild aerobic training at the LT is an effective method of improving the level of serum HDL-c, the TC/HDL-c ratio and aerobic capacity in the older patients with hypertension.