REFERENCE INTERVAL OF MAXIMAL OXYGEN UPTAKE (VO₂max) AS ONE OF THE DETERMINANTS OF HEALTH-RELATED PHYSICAL FITNESS IN JAPAN / 体力科学

Maximal oxygen uptake (VO₂max) is an important determinant of health-related physical fitness. In 2006, the Japan Ministry of Health, Labour and Welfare (JMHLW) officially declared a standard reference value and reference interval of VO₂max. However, these values were established on the basis of a systematic review of reports published in Western countries and were not based on actual VO₂max data of the Japanese population. Therefore, we conducted a study entitled “The study on a minimum zone of VO₂max as one of the determinants of health-related physical fitness in Japan” from 2004 to 2006 as a project of the Japanese Society of Physical Fitness and Sports Medicine (JSPFSM). In addition, we collected published VO₂max data of the Japanese population from the JSPEFM website. In the present study, we attempted to determine the reference interval of VO₂max with regard to age, gender, and different methods of exercise. Further, we established a cut-off value of VO₂max for determining metabolic syndrome (MS).1. Reference interval of VO₂maxFor both men and women, 325 and 364 values for the treadmill exercise, and 1175 and 2178 values for the cycle ergometer exercise, respectively, were collected. This data revealed a balanced distribution of VO₂max with regard to age. Data that satisfied the VO₂max criterion were used for the analysis. These data were regressed to age on gender and methods of exercise. The percentage of VO₂max was calculated using the following equation: %VO₂max = measured VO₂max × 100/age-estimated VO₂max. The iterative truncation method was used to calculate the reference interval of VO₂max (70%∼130% VO₂max) from the crude data of %VO₂max, and then converted to actual VO₂max. Thus, the reference interval of VO₂max for healthy Japanese was determined with regard to age, gender, and different methods of exercise.2. Cut-off value of VO₂max for determining MSUsing the VO₂max data of subjects with body mass index (BMI) of ≧25kg/m² and ≧2 MS risk factors, and the data of subjects with normal BMI without any risk factors, we calculated sensitivity and specificity. The cut-off value was determined using the receiver operating characteristic curve. This cut-off value was defined as the critical value of VO₂max that should be maintained to avoid MS and remain healthy.

REFERENCE RANGE AND ADOPTIVE CRITERION FOR MAXIMAL OXYGEN UPTAKE (VO2max) IN CONSIDERATION OF AGE AND GENDER-REFERENCE RANGE FOR VO2max ATTAINED BY MEANS OF THE ITERATIVE TRUNCATION METHOD / 体力科学

The existing adoptive criterion for VO<SUB>2</SUB>max was created for physically fit subjects who were soldiers and/or sportsmen. However, VO<SUB>2</SUB>max is widely used at present as one of the health-related physical fitness determinants from children to aged persons. It might be appropriate to determine the criterion and the critical values for VO<SUB>2</SUB>max in consideration of age and gender.<BR>The present study attempted to determine the reference range and critical values of the criterion for VO<SUB>2</SUB>max using the iterative truncation method. Voluntary VO<SUB>2</SUB>max was measured in 548 healthy volunteers, aged 8 to 82 years, using a treadmill. The % VO<SUB>2</SUB>max was calculated using the equation of %VO<SUB>2</SUB>max=measured VO<SUB>2</SUB>max × 100 gage-estimated VO<SUB>2</SUB>max. Crude data of %VO<SUB>2</SUB>max was applied to the iterative truncation method, and the reference range of %VO<SUB>2</SUB>max (70-130%VO<SUB>2</SUB>max) was determined. Physiological and biochemical parameters, within the values of 70-130%VO<SUB>2</SUB>max, were converted to a percentage using a similar equation of %VO<SUB>2</SUB>max. The value corresponding to 10% of the lower area of the distribution of each parameter was defined as the critical value, which was the minimum level to adopt as the VO<SUB>2</SUB>max. Taking a single or combined application of the critical value of each parameter, the adoptive ratio of VO<SUB>2</SUB>max was investigated.<BR>The present study indicated that there was no difference between VO<SUB>2</SUB>max selected by the iterative truncation method and that obtained by the existing criterion for VO<SUB>2</SUB>max. The combination of the critical value of HRmax and bLAmax was recommended as a criterion of VO<SUB>2</SUB>max. The reference value, critical value of VO<SUB>2</SUB>max and the critical real value of each parameter were shown as a mean of every 5-year interval with the distinction of gender.

CARDIO-VASCULAR FUNCTIONS AND PHYSICAL FITNESS OF PREADOLESCENTS AND ADOLESCENTS / 体力科学

Orthostatic Disregulation (OD, a kind of dysautonomia) is a syndrome which indicates disfunction of vessel contraction reflex during static standing. OD patients often show some symptoms of fainting, dizziness, headache and the like or syncope when they are holding orthostatic posture. OD is more recognized especially in preadolescence and adolescence periods (9-15 yrs.) . Brück & Oltmann (1957), Okuni (1958) etc, have reported details about OD.<BR>The purpose of this study was to obtain and discuss details relating to recent appearance of OD, physique, growth characteristics, cardio-vascular functions and physical fitness on OD children by the questionnaire method and some experiments.<BR>2, 227 children in elementary and junior high school in Yokohama and Kamakura cities as sub jectswere first screened by the questionnaire. And 165 subjects out of 2, 227 were at random selected for data on Schellong standing test, passive head-up tilt and distance running.<BR>The value of 9-29%, which was the ratio of false OD (+) appearance by the questionnaire method in this study, was recognized higher than the value of 5-20% by previous studies'. Physique on false OD (+) children was somewhat lean in comparison with the normal. And they had more height increase than the normal.<BR>In physical fitness, distance running, 50 m dash, broad jump, ball throw, chinning exercise and back pull-over tests, OD children were inferior than the normal.<BR>A concrete datum in syncope for standing was got in this study. When an OD child exhibited syncope, systolic blood pressure became 78 mmHg (rest 120-130 mmHg) and heart rate became 76 beats per minute (standing before syncope 100-110 beats per minute) . T wave in II, <SUB>a</SUB>V<SUB>F</SUB> and P wave in II, III (depression, negative waves etc.) of ECG varied from resting ECG. Judging from these data about ECG and blood pressure on standing test, passive head-up tilt, it was indicated that a reflex system of vessel contraction on OD child didn't work well, and that the heart of OD child was much stressed by gravity in orthostatic posture and changing posture than the normal.<BR>In addition, a fact was proven that false OD (+) children (39.1% boys and 48.2% girls) didn't like sports and physical activities comparing with the normal (16.4% boys and 23.5% girls), It was statistically significant. Therefore, it is estimated that there is a relationship between appearance of OD and physical activities in daily life.