The purpose of this study was to examine the validity of a 20-m shuttle-run test as an aerobic fitness test for Japanese children, adolescents, and young adults. Participants were 62 boys and 70 girls aged 8–17 years and 56 men and 99 women aged 18–23 years. Stepwise regression analysis was used to elucidate the relationship between shuttle-run performance, age, gender, and anthropometric parameters (as independent variables) and peak oxygen uptake (VO2peak), determined directly on a treadmill, as a dependent variable. We observed high multiple correlations for adults (R2 = .88) and for children and adolescents (R2 = .80). Therefore, it is suggested that our multiple regression equations are more appropriate for predicting VO2peak in Japanese children, adolescents, and adults.

The purpose of present study was to assess the relationship between anaerobic threshold (AT) and performances in three different distance races (i.e., 5 km, 10 km, and 10 mile). AT, VO2 max, and related parameters for 17 young endurance runners aged 16--18 years tested on a treadmill with a discontinuous method. The determination of AT was based upon both gas exchange and blood lactate methods. Performances in the distance races were measured within nearly the same month as the time of experiment. Mean AT-VO2 was 51.0 ml . kg-1 . min-1 (2.837 l . min-1), while VO2 max averaged 64.1 ml . kg-1 . min-1 (3.568 l . min-1). AT-HR and %AT (AT-VO2/VO2 max) were 174.7 beats . min-1 and 79.6%, respectively. The correlations between VO2 max (ml . kg-1 . min-1) and performances in the three distance races were not high (r = -0.645, r = -0.674, r = -0.574), while those between AT-VO2 and performances was r = -0.945, r = -0.839, and r = -0.835, respectively. The latter results indicate that AT-VO2 alone would account for 83.9%, 70.4%, and 69.7% of the variance in the 5 km, 10 km, and 10 mile performances, respectively. Since r = -0.945 (5 km versus AT-VO2) is significantly different from r = -0.645 (5 km versus VO2 max), the 5 km performance appears to be more related to AT-VO2 than VO2 max. It is concluded that individual variance in the middle and long distance races (particularly the 5 km race) is better accounted for by the variance in AT-VO2 expressed as milliliters of oxygen per kilogram of body weight than by differences in VO2 max.

No abstract

Within this population, those with high biomechanical treadmill walking economy are the more habitually physically active. Treadmill belt speed, but not walking time, affects biomechanical walking economy.

This study was undertaken to compare the contribution of both the anaerobic threshold (AT) and onset of blood lactate accumulation (OBLA) with endurance performance in eleven non-endurance trained active male adults. AT determination was based upon both blood lactate and gas exchange criteria, while OBLA was determined as the point corresponding to a blood lactate concentration of 4 mmol X 1(-1). A dependent t-test revealed significantly higher values for OBLA related variables as compared with corresponding AT related variables, thereby validating the comparison of these two categories of variables in relation to endurance performance. Approximately 67, 60, 37, and 50% of the variance in endurance performance were accounted for by AT-VO2 (ml X kg-1 X min-1), AT-WR, OBLA-VO2 (ml X kg-1 X min-1), and OBLA-WR, respectively. When AT-HR (X2) was added to the AT-VO2 (X1) as another predictor, the contribution of these variables to endurance performance increased appreciably to 84%. The resultant multiple regression equation was Y = -4.564 X1 + 2.68 IX2 + 90.6 (SEE = 9.9 s). Consequently, it is suggested that variables related to an abrupt increase in blood lactate, together with several gas exchange responses, could explain endurance performance in a shorter distance to a greater extent than variables related to a rigid threshold of 4 mmol X 1(-1).

Facial cooling combined with either cold or warm air inhalation causes the greatest EIB, as compared with the isolated challenge with cold air inhalation. We suggest that vagal mechanisms play a major role in exercise and cold-induced bronchoconstriction.

Ethanol extract of Eleutherococcus senticosus Maxim. was discreetly examined as regards its effect on the maximal working capacity of man, using six male adolescents. Single, blind, cross-over studies were conducted where the extract treatment was compared with no treatment and with placebo treatment. Significant increase was noted in all four parameters recorded in the tests due to extract administration. Especially striking was 23. 3% increase in total work due to the extract compared with only 7.5% rise due to the placebo. This increase in total work seemed to be partially attributable to the improvement of subject's bodily oxygen metabolism that was reflected in the increase in maximal oxygen uptake and that in maximal oxygen pulse.

This is the first to clarify the prevalence of LGBT among youth in Japan. It has been suggested that such individuals in Japan, as in other countries, are at risk for physical and mental health concerns, thereby necessitating social and medical intervention. Further investigation in these areas will be needed.