The purpose of this study was to investigate the effect of L-citrulline ingestion on ECG QT interval. To accomplish this purpose, nine male subjects (age: 23.4±0.5 years, weight: 57.7±5.6 kg) participated, who had no history of cardiovascular or respiratory function disorders. Each subject performed two tests (L-citrulline and placebo ingestion) on a separate day. ECG was taken before, and 60 min and 90 min after L-citrulline ingestion. The heart-rate-corrected QT interval (QTc) decreased significantly 60 min (p=0.0004) and 90 min (p=0.011) after L-citrulline ingestion. However, there were no significant changes after placebo ingestion. In addition, the interaction between L-citrulline ingestion and placebo was significant (two-way ANOVA: interaction, p=0.010). Our major finding was that L-citrulline ingestion decreases the QT interval in healthy subjects. This result suggests that transient L-citrulline ingestion may shorten the time required to complete myocardial depolarization and repolarization.

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The present study aimed to examine the sex differences in the cross-sectional areas of the psoas major, quadriceps femoris, hamstrings, and adductors in high school track and field athletes and nonathletes. The cross-sectional areas of the psoas major at L4-L5 and three thigh muscles at the mid-thigh were determined in the right side of the body using magnetic resonance imaging in 61 sprinters (29 boys and 32 girls), 50 jumpers (28 boys and 22 girls), 33 throwers (18 boys and 15 girls), and 40 nonathletes (20 boys and 20 girls), aged from 16 to 18 yrs. On the whole, the cross-sectional area for every muscle group was greater in the athletes than in the nonathletes and in the boys than in the girls. The average value of the cross-sectional area for the girls as a percentage of that for the boys in every subject group was lower in the psoas major (57.6–64.7%) than in the thigh muscles (67.8–82.9%). Among the thigh muscles, the muscle group which showed significant sex differences in the ratio of cross-sectional area to the two-third power of lean body mass was limited to the quadriceps femoris in the sprinters and nonathletes and hamstrings in the throwers. However, the ratio for the psoas major was significantly higher in the boys than in the girls in all subject groups. The current results indicate that, although regular participation in sports training during adolescence promotes hypertrophy in the psoas major and thigh muscles in not only boys but also girls, a greater sex difference exists in the muscularity of the psoas major than of the thigh muscles, in athletes and nonathletes.

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Several contact-type anthropometric instruments have been previously established for use in population surveys that contribute to the construction of anthropometric databases. Manual anthropometric measurements need to comply with or fulfill the following conditions: anatomical landmarks (term, location, and detecting method); measuring methods (item and subject's posture); five contact-type instruments (anthropometer, large sliding caliper, sliding caliper, spreading caliper, and tape measure); and well-trained examiners. Here, two manual non-contact-type portable anthropometric instruments were developed for measuring small regions such as the head and for larger regions such as the trunk of the human body, and for obtaining anatomical longitudinal parameters (length, height, breadth, and depth) based on the principle of projection by spot irradiation using laser markers. A new landmark-detecting method, based on the idea of visual landmarks, was proposed instead of the conventional palpation method (direct feeling with fingers), which was not appropriate for a non-contact measuring system. The accuracy of each instrument was tested using industrial tools, and performance was compared with contact-type instruments using a skeletal model (four measurements), a free posture manikin (eight measurements), and the healthy human body (five males and five females; nine measurements). Measurement errors and visual inspection to detect landmarks were discussed. The instruments show applicability to non-contact anthropometry.

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In this study, curvilinear regression was applied to the relationship between BMI and body fat percentage, and an analysis was done to see whether there are characteristic changes in that curvilinear regression from elementary to middle school. Then, by simultaneously investigating the changes with age in BMI and body fat percentage, the essential differences in BMI and body fat percentage were demonstrated. The subjects were 789 boys and girls (469 boys, 320 girls) aged 7.5 to 14.5 years from all parts of Japan who participated in regular sports activities. Body weight, total body water (TBW), soft lean mass (SLM), body fat percentage, and fat mass were measured with a body composition analyzer (Tanita BC-521 Inner Scan), using segmental bioelectrical impedance analysis & multi-frequency bioelectrical impedance analysis. Height was measured with a digital height measurer. Body mass index (BMI) was calculated as body weight (km) divided by the square of height (m). The results for the validity of regression polynomials of body fat percentage against BMI showed that, for both boys and girls, first-order polynomials were valid in all school years. With regard to changes with age in BMI and body fat percentage, the results showed a temporary drop at 9 years in the aging distance curve in boys, followed by an increasing trend. Peaks were seen in the velocity curve at 9.7 and 11.9 years, but the MPV was presumed to be at 11.9 years. Among girls, a decreasing trend was seen in the aging distance curve, which was opposite to the changes in the aging distance curve for body fat percentage.

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This study investigated predictors of outcome for a three-month group-exercise program among a community-dwelling Japanese population aged over 65 (n=42). The primary outcome variable was health-related quality of life (HRQOL) using the Short Form 36 (SF-36). Candidate predictors included demographic variables, medical history of chronic diseases, and lifestyle-related factors, including self-reported home exercise at baseline examination. At follow-up, only the vitality domain of the SF-36 was significantly improved. Self-reported home exercise and younger age at baseline were significant predictors of a good outcome in the mental and physical components, respectively, of the SF-36. These results indicate that group exercise may be effective to improve the vitality component of HRQOL for Japanese seniors. However, the effects on the physical components of HRQOL are limited. Home exercise and younger age may influence the effects of group exercise on HRQOL for this population.

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