Determining total energy expenditure in 3-6-year-old Japanese pre-school children using the doubly labeled water method.

The doubly labeled water (DLW, 2H218O) method for calculating the total production of CO2 over several days is currently considered to be the most accurate technique for the measurement of total energy expenditure (TEE), and the results obtained using this method have been used to review energy requirements. Presently, there is limited data available on TEE in Japanese children. The objective of this study was to assess the TEE in pre-school Japanese children using the DLW method. We used a cross-sectional population of 140 children (69 boys and 71 girls) aged 3-6 years. TEE was measured using the DLW method over 8 days under free-living conditions. The average weights (kg) of the boys and girls were 15.6 ± 2.5 and 15.0 ± 2.1 for the 3-4 years old and 19.8 ± 3.8 and 19.6 ± 2.7 for the 5-6 years old, respectively. The corresponding TEE (kcal/day) was 1260.9 ± 357.8 and 1265.2 ± 408.0, and 1682.3 ± 489.0 and 1693.1 ± 473.3, respectively, showing a significant difference with respect to age. Furthermore, TEE per body weight (kcal/kg/day) was 83.2 ± 29.2 and 84.9 ± 26.6, and 85.4 ± 23.2 and 86.7 ± 22.6, respectively. However, when TEE was adjusted for body weight or fat-free mass, there were no age or sex differences. We conclude that in Japanese children, TEE in those aged 3-4 years was similar to the current Ministry of Health recommendations. However, TEE in children aged 5-6 years was slightly higher than the recommendations. Based on these findings, the present results obtained from a large number of participants will provide valuable reference data for Japanese children.

Effects of high-intensity swimming training on the bones of ovariectomized rats.

PURPOSE: This study was performed to assess the effects of high-intensity intermittent swimming training(HIT) on bone in ovariectomized rats. METHODS: Six-week-old female Sprague-Dawley rats were randomly assigned to either sham operation or bilateral ovariectomy. After surgery, they were divided into the following four groups: 1) sham-operated sedentary (S), 2) sham-operated exercise training (SE), 3) OVX sedentary (O), 4) OVX exercise training (OE) 5) OVX given 17ß-estradiol (OE2) and 6) OVX exercise training and given 17ß-estradiol (OEE). SE, OE and OEE rats were used extremely high-intensity swim exercise. The rats repeated fourteen 20-s swimming bouts with a weight equivalent to 14, 15, and 16% of body weight for the first 5, the next 9, and the last 5 days, respectively. Between exercise bouts, a 10-s pause was allowed. HIT was originally designed as an exercise method; a method that very quickly induces an increase in the maximum oxygen intake (Tabata I et al., 1996). OEE and OE2 rats were subcutaneously injected ethanol with 25µg/kg body weight 17ß-estradiol 3 times per week. RESULTS: Bone strength, bone mineral density and trabecular bone parameters were measured after a 8-weeks experimental period. Bone strength was significantly higher in the SE, OE, OE2 and OEE group compared with the O group. BV/TV was significant increase in the SE, OE groups compared with the O group. BMD showed no difference in the OE group compared with the O group. CONCLUSION: This study demonstrate some beneficial effects of postmenopausal osteoporosis of high-intensity intermittent swimming training on bone structure and strength.

Effects of skim milk powder intake and treadmill training exercise on renal, bone and metabolic parameters in aged obese rats.

PURPOSE: we aim to examine whether adding exercise has impact on obesity prevention and bone metabolism in senior rats, to which dietary obesity was induced through skim milk intake. METHODS: We used 47, 14-week old Sprague -Dawley (SD) female rats (CLEA Japan, Inc.). The Rats were separated into four random groups: 1) a Non-Ex group with a normal diet (n = 12), 2) an Ex group with a normal diet (n = 12), 3) a Non-Ex group with a skim milk diet (n = 11), and 4) an Ex group with a skim milk diet (n = 12). As the exercise for each Ex group, rats ran on a treadmill starting at 27-week old (TREADMILL CONTROL LE8710 and TREADMILL CONTROL LE8700, Harvard Bioscience). Training protocol stipulated a frequency of five times a week for 12 weeks. RESULTS: The leptin concentration differed with dietary content: compared to the Ex group with a skim milk diet, Non-Ex and Ex groups with a normal diet showed significantly higher values (p < 0.05). The Ex group had significantly lower values in both the normal diet and skim milk diet groups with or without exercise (p < 0.05). Compared to the Non-Ex group with a normal diet, BS/BV (mm(2)/mm(3)), BV/TV (%), Tb.Th (µm), TBPf (/mm) and Tb.N (/mm) had significantly lower in the Ex group, the Ex and Non-Ex groups with a whey protein diet, and the Ex group with a skim milk protein diet (p < 0.05). CONCLUSION: These findings suggest that senior female rats fed SMP would have higher bone structural and strength parameters than rats fed a normal diet.

Relationship between performance test and body composition/physical strength characteristic in sprint canoe and kayak paddlers.

OBJECTIVE: Canoe sprint is divided into canoe and kayak. The difference between the two competitions is in physical performance. The aim of the present study was to compare and investigate the relationship between physical characteristics and fitness between the two canoe sprint competitors. METHODS: Subjects were 11 canoe paddlers (C) and 12 kayak paddlers (K). They underwent anthropometric characteristics, body composition and fitness tests, and 120 s all-out tests using a canoe and kayak ergometer. The unpaired t-test was used to test for significant differences between disciplines, while Pearson's correlation coefficient was used to examine the association between each measurement item and the performance test. RESULTS: The age, height, body mass, body mass index, and total body fat were, C: 20.6±0.9 yr, 172.8±5.2 cm, 70.8±7.8 kg, 23.7±1.9, 14.4%±3.5%; and K: 19.7±1.2 yr, 172.8±5.3 cm, 69.5±7.8 kg, 23.2±2.1, 12.1%±3.6%, respectively. No significant differences were seen in any of the items for physical characteristics or fitness between C and K. A correlation analysis of performance tests and each measurement item revealed a positive correlation with low-speed isokinetic knee extension and flexion strength for C only (extension: r=0.761; flexion: r=0.784; P<0.01). In addition, performance tests were positively correlated with the circumference of arm (upper arm: r=0.876; forearm: r=0.820; P<0.01) and lower limb (thigh: r=0.781; calf: r=0.753; P<0.01) in C and with height (r=0.549, P<0.05), arm span (r=0.639, P<0.05), and leg length (r=0.621, P<0.01) in K. CONCLUSION: We suggest that the factors correlating with the performance test differ depending on the competitions.

The ACTN3 R577X polymorphism is associated with muscle power in male Japanese athletes.

In this study, we investigated whether the ACTN3 R577X polymorphism is associated with muscular power in Japanese collegiate athletes by analyzing the mean and peak power results of a 30-second Wingate anaerobic test (WAnT) with respect to the ACTN3 R577X genotype in 253 Japanese athletes (144 men and 109 women). Each athlete performed a 30-second WAnT with a resistance equal to 7.5% of his or her body weight. Genotyping for the ACTN3 R577X (rs1815739) polymorphism was performed using the TaqMan approach. The ACTN3 R577X genotypes exhibited a Hardy-Weinberg equilibrium distribution in our population. The relative and absolute mean power results of the 30-second WAnT did not differ significantly among the genotypes. However, the relative peak power result of the WAnT was significantly higher in the R-allele-dominant model groups than in the XX group in male but not female athletes. These results suggest that the ACTN3 R allele is associated with the relative peak power during the WAnT in male Japanese collegiate athletes.

The ACTN3 XX genotype's underrepresentation in Japanese elite wrestlers.

PURPOSE: To examine the relationship between ACTN3 polymorphisms and level of athletic performance in Japanese wrestlers. METHODS: The control group consisted of 243 healthy Japanese individuals. The authors divided 135 wrestlers into 3 groups based on their results in national or international competitions. They classified as elite 24 wrestlers who had placed in the top 8 in a world championship or participated in Olympic games, 28 wrestlers who had participated in world championships or become champions in Japan's national championships were classified as subelite, and 83 wrestlers were classified as national (N-W, ie, national-level wrestler). In addition, the authors combined the elite and subelite to form the classification international-level wrestlers (I-W). RESULTS: The frequency of the null X allele and the XX genotype were significantly lower in the I-W group than in the control group. However, there was no significant difference in ACTN3 genotype or allele frequency between the N-W and control groups. The frequency of the ACTN3 XX genotype in the elite groups was lower than that of all groups, and a linear tendency was observed between ACTN3 XX genotype and athletic status. CONCLUSIONS: In conclusion, the data indicated that ACTN3 polymorphisms were related to athletic performance in Japanese wrestlers.

Higher frequency of the ACTN3 R allele + ACE DD genotype in Japanese elite wrestlers.

In this study, the authors investigated the association between the ACTN3 and angiotensin-converting enzyme (ACE) genotypes and the performance of 135 Japanese elite male wrestlers. Fifty-two wrestlers had participated in world championships, including the Olympic Games, or had placed first in Japanese national championships and were classified as "international." The remaining 83 wrestlers were classified as "national." The control group consisted of 333 healthy Japanese college students majoring in physical education. In the ACTN3 genotype distribution, a significant difference between the international and control groups was observed (p < 0.05). The ACE genotype distribution and allele frequency of all wrestlers significantly differed from those of the control subjects (p < 0.001). As compared with the control group, the odds ratio of the ACTN3 R allele + ACE DD genotype being international or national was 3.85 (95% confidence interval [CI], 2.10-7.03) or 1.37 (95% CI, 0.79-2.36), respectively. Our data suggest that the combination of ACTN3 and ACE gene polymorphisms is associated with the athletic status of Japanese elite wrestlers.

Opuntia humifusa supplementation increased bone density by regulating parathyroid hormone and osteocalcin in male growing rats.

We investigated the effect of Opuntia humifusa (O. humifusa) supplementation on bone density and related hormone secretion in growing male rats. Sixteen six-week-old male Sprague-Dawley rats were randomly divided into two groups; control diet group (CG, n = 8), and experimental diet group (EG, n = 8). The rats in the CG were given a control diet and those in the EG were given 5% O. humifusa added to the control diet for eight weeks. The serum OC level of the EG was significantly higher than that of the CG, and the serum parathyroid hormone (PTH) level of EG was significantly lower than that of the CG. In addition, the femoral and tibial BMD of the EG were significantly higher values than those of the CG, and the tibial BMC of the EG was significantly higher than that of the CG. These results suggest that O. humifusa supplementation has a positive effect on bone density by suppressing PTH and increasing the OC level in growing male rats.

Examination of the reliability of the portable calorimeter.

1. The present study was performed in order to determine the reliability of the portable calorimeter. 2. Resting energy expenditure (REE) was measured by two different apparatuses: one was the typical gas analyser, the other was the portable calorimeter. 3. Although there are differences among individuals, unless the subject has been exposed to severe physical activity prior to the measurement, a suitable resting time prior to the measurement of resting metabolic rate is 10 min. 4. For the measurement of resting metabolic rate, fluctuations in respiratory quotient (RQ) are extremely small; there is greater fluctuation due to variations in respiration. Therefore, for the screening of energy consumption, the use of a fixed value for RQ is sufficient when measuring only oxygen uptake. 5. Respiratory fluctuations vary from person to person and it is not possible to make stable measurements in 1 or 2 min. Therefore, a suitable measurement time for resting metabolic rate is from 3 to approximately 6 min. 6. The results indicate that this portable calorimeter is a useful apparatus for measuring REE in the field.

Effects of habitual chitosan intake on bone mass, bone-related metabolic markers and duodenum CaBP D9K mRNA in ovariectomized SHRSP rats.

We have demonstrated that the habitual intake of chitosan can decrease bone mass in ovariectomized (OVX) SHRSP rats fed a low-Ca diet (0.1%). In the present study, we examined both the etiology of bone loss induced by dietary chitosan and the preventive effect of vitamin C supplementation. Rats were OVX and maintained on one of the following diets for 6 wk: 10% cellulose (CE). 10% chitosan (CH) or 10% chitosan with sodium ascorbate (CHVC). CH caused a significant reduction in bone mineral density (BMD) and stiffness in femurs and the fourth lumbar vertebrae (L4). There was no significant difference in intestinal Ca absorption between CH and CE, whereas CH intake significantly reduced intestinal P absorption. The bone loss in CH rats was accompanied with an increase in urinary Ca excretion and a decrease in serum Ca as well as a significant increment In serum PTH and 1,25(OH)2D3. The vitamin D receptor and calcium binding protein D9K mRNAs were also significantly increased in the duodenum of CH rats. Vitamin C supplementation to CH caused an increase in the Ca and P contents of femurs as well as BMD of the L4, with a decrease in urinary Ca excretion. These results indicate that dietary chitosan with low Ca intake possibly induces the loss of bone mass by enhancing urinary Ca excretion rather than by inhibiting Ca absorption, and that vitamin C supplementation could prevent bone loss caused by chitosan through the increment of retained Ca followed by suppression of urinary Ca excretion.

Examination of the reliability of the portable calorimeter.

1. The present study was performed in order to determine the reliablility of the portable calorimeter. 2. Resting energy expenditure (REE) was measured by two different apparatuses: one was the typical gas analyser, the other was the portable calorimeter. 3. Although there are differences among individuals, unless the subject has been exposed to severe physical activity prior to the measurement, a suitable resting time prior to the measurement of resting metabolic rate is 10 min. 4. For the measurement of resting metabolic rate, fluctuations in respiratory quotient (RQ) are extremely small; there is greater fluctuation due to variations in respiration. Therefore, for the screening of energy consumption, the use of a fixed value for RQ is sufficient when measuring only oxygen uptake. 5. Respiratory fluctuations vary from person to person and it is not possible to make stable measurements in 1 or 2 min. Therefore, a suitable measurement time for resting metabolic rate is from 3 to approximately 6 min. 6. The results indicate that this portable calorimeter is a useful apparatus for measuring REE in the field.

Effect of the moderate exercise on performance in upper/lower limb during long term bed rest.

The purpose of this study was to investigate that considers the influence of the moderate exercise has on the upper limbs and the legs during 21 days head down bed rest. Therefore motor evoked potential (MEP) induced by transcranial magnetic stimulation (TMS) in lower leg muscles of four healthy subjects were investigated before/after and during bed rest. There were no significant differences statistically between soleus MEPs before and after bed rest in all subjects. However there were decreased tendancy in MEPs during non-exercise group. And then there were not change discriminal ability on differential threshold of weight sensory in scale test in all subjects during head down bed rest. Theses results indicate that the assign cognitive performance, sensory in scale for upper limb no changes during and after head down bed rest.