Development of a physical fitness evaluation method that accounts for individual growth status in 6-17 year old students using data obtained in 2009 / 体力科学

Evaluation of the physical fitness level of children and adolescents must include consideration of individual growth rates. This study evaluates the relationship between height and physical fitness in a large sample of 6-17 yr students. Physical fitness test scores were calculated for every 1 cm height group and used to generate quadratic regression equations. Physical fitness data reported by the Ministry of Education, Culture, Sports, Science and Technology in Japan (MEXT) were compared with estimated values obtained using our regression equations. The differences between the values reported by MEXT and our estimated values were very small. Comparison of physical fitness T-scores calculated based on school grade averages with T-scores based on means calculated using our regression equations indicated that shorter height students had lower T-scores if school grade averages were used for the calculation. In conclusion, in elementary and junior high school students, it is important to evaluate physical fitness level relative to individual physical growth.

Effects of Moderate-Intensity Endurance Exercise on Reactive Oxygen Species Production and Leukocyte Activation Markers / 日本補完代替医療学会誌

The purpose of this study was to examine effects of moderate-intensity endurance exercise on reactive oxygen species production and leukocyte activation markers in young and middle-aged persons. Blood samples were collected before and after the jogging of 10 km. Although cytokines recruiting and priming neutrophils and monocytes were released into the circulation and functional after the jogging of 10 km, reactive oxygen metabolites-derived compounds (d-ROMs) were not significantly increased. It was indicated that chemokines and leukocyte activation markers at rest were increased with aging, and that might be accompanied by the higher level of d-ROMs in the elderly.<br>

Systolic blood pressure responses to pedalling exercise / 体力科学

The response of systolic blood pressure (SBP) to pedalling exercise was studied in 32 healthy young men. The subjects performed the exercise at different intensities for 3 min using an incremental loading method. The first work load was 30W and increased by 30W until the heart rate (HR) reached about 170 bpm. SBP at HR 100. 160 bpm (SBP@HR 100-160) was calculated from the cubic regression equation in each subject. Mean SBP and SEM at HR 100, 110, 120, 130, 140, 150, 160 were 143.9 (2.49), 152.9 (2.79), 161.6 (3.02), 170.0 (3.16), 177.8 (3.25), 184.5 (3.34), and 189.7 (3.45) mmHg, respectively. However, the rate of elevation of SBP was zero at HR 175 bpm, which was calculated from the cubic regression equation. This may indicate that SBP is inhibited by baroreceptors and other factors at HR above 170 bpm. There were no significant relationships between SBPs@HR 100-160 and indices of aerobic capacity such as maximal oxygen consumption or PWC 170. Double product (DP) as an index of oxygen consumption by cardiac muscle increased with HR without any reduction in its rate of elevation during exercise.

Effects of breath holding in air on cardiac responses in man / 体力科学

Healthy male subjects were asked to hold their breath in air at the tidal inspiratory level, and time-dependent changes in mean values of several parameters of cardiovascular function were studied. The heart rate increased abruptly after the beginning of breath-holding and then decreased slightly with time. The stroke volume (SV) remained significantly low until the end of breath-holding, so that the cardiac output was decreased in parallel. With regard to the systolic time interval, the totai eiectromechanical systole and the left-ventricular systolic time (LVET) were not significantly changed, whereas the pre-ejection period (PEP) was markedly prolonged. Therefore, ratios of PEP/LVET and SV/LVET were increased and decreased with time, respectively. As the systolic, and in particular the diastolic blood pressures were elevated, the pulse pressure was reduced. Ratios of the diastolic and systolic times in relation to the heart rate at rest, during breath-holding and during recovery after breath-holding were all proved to be described by a single regression curve. However, the ratios obtained for cycling exercise at various heart rates showed a marked shift above the curve. These results clearly indicate that cardiac performance is lowered during breath-holding in air.

Comparisons of left ventricular systolic and diastolic times in exercise between trained and untrained men / 体力科学

The systolic time intervals (STI's) and the diastolic time (DT) as functions of the RR interval during exercise were proved to be described by cubic regression equations that converge to the origin of the coordinates. Using the equations, we compared I) the systolic time and DT of trained and untrained men, and II) examined the relations between parameters of STI's. I) Forty healthy male subjects aged 19-22 years old were divided into three groups, i, e., 8 long distance runners (group LD), 16 men with relatively high fitness (group A) and 16 men with relatively low fitness (group B) . They performed submaximal exercise test using a cycle ergometer for measuring the time of electromechanical systole (QS<SUB>2</SUB>) and DT. After test, maximal exercise test was conducted to determine the maximal heart rate (HRmax) in each subject. Means±SD of the minimum QS<SUB>2</SUB> and the minimum DT of the 40 subjects predicted from the regression equations at the HRmax were 209.7±12.5 and 108.2±15.6 ms, their ratio being about 2: 1. The QS<SUB>2</SUB> was significantly shorter, whereas DT was longer in the group LD than in the groups A and B at the HR of more than 120 bpm. II) Ten healthy male subjects aged 19-22 years old performed submaximal exercise to clarify the relations between any two of QS<SUB>2</SUB>, the left ventricular ejection time (LVET) and the preejection period (PEP) at the same HR: there were positive and negative significant correlations between QS<SUB>2</SUB> and LVET, and between LVET and PEP, respectively, at the HR of more than 100 bpm. These results reveal that, when the HR is increased in exercise, the left ventricular systolic time (QS<SUB>2</SUB>) is shortened while the diastolic time is lengthened for the subjects trained as long distance runners. The shortening of the systolic time is mainly caused by shortening of LVET. The changes in the systolic and diastolic times suggest that contractility of cardiac muscle is enhanced during exercise of above moderate intensity after an extensive period of the aerobic training.

ON THE ENERGY METABOLISM OF ROPE SKIPPING / 体力科学

In this study, energy consumption of three types of basic rope skipping was measured, together with an investigation of work intensities. The subjects were 5 healthy adult male. The results of this study were as follows :<BR>1) The average relative metabolic rate (RMR) of 1 skip (one skip to one forwardturn of rope), 2 skip (double skip to one forward-turn of rope) and running skip were 13.6, 11.7 and 10.3, respectively, and it was noted that work intensities decrease in order of 1 skip, 2 skp and running skip.<BR>2) On the three types of five minute rope skipping, the oxygen intake for the last one minute of exercise of 1 skip was equivalent to 63.7-78.0% of maximal oxygen intake, and in cases of 2 skip and running skip were 57.5-76.3% and 56.8-67.2%, respectively.<BR>3) When skip frequencies of 1 skip were 92, 120 and 156 skips/min, respectively, oxy-gen requirement for 120 skips/min was the lowest, therefore, it was noted that skip fre-quency of 120 skips/min was optimal.