An academic cooperation between the Japan Sports Nutrition Association (JSNA) and the Korean Society for Exercise Nutrition (KSEN).

PURPOSE: The Japan Sports Nutrition Association (JSNA) is an academic society that aims to contribute to people's health and the development of sports in Japan. METHODS: After numerous communication and academic events, the JSNA and the Korean Society for Exercise Nutrition (KSEN) exchanged a Memorandum of Understanding (MoU) in 2018. RESULTS: Based on the MoU, the JSNA and KSEN organized academic exchange events until the Coronavirus Disease 2019 pandemic and subsequent travel restrictions and lockdowns. CONCLUSION: After four years of the pandemic and the downgrading of Coronavirus Disease 2019 infection risk, it is hoped that academic exchanges between the societies will resume gradually and enhance members' recognition of the cooperation between the JSNA and KSEN for active collaborations in the future.

Effect of Vitamin D Supplementation on Body Composition and Physical Fitness in Healthy Adults: A Double-Blind, Randomized Controlled Trial.

INTRODUCTION: This study aimed to clarify whether 1 year of vitamin D3 supplementation has a direct effect on body composition and physical fitness in healthy adults. METHODS: Ninety-five participants randomly received either 420 IU vitamin D3 per day (n = 48) or placebo (n = 47) in a double-blind manner for 1 year. Lean body mass and percentage body fat were determined. Physical fitness including hand grip strength, leg extension power and cardiorespiratory fitness (CRF) were assessed. Serum 25-hydroxyvitamin D (25[OH]D) and 1,25-dihydroxyvitamin D (1,25[OH]2D) concentrations were assessed using ELISA kits. RESULTS: Serum 25(OH)D and (1,25[OH]2D) concentrations significantly increased by approximately 11.2 ± 9.2 ng/mL (pinteraction <0.001)and 7.0 ± 7.8 pg/mL (pinteraction <0.001) after 1 year of vitamin D3 supplementation respectively. Lean body mass significantly increased from 43.8 ± 9.6 to 44.3 ± 9.8 kg in vitamin D group, while no change was observed in placebo group (from 42.6 ± 8.9 to 42.4± 8.9 kg) after 1 year intervention. Furthermore, no treatment effects on other indicators of body composition and physical fitness were observed. CONCLUSIONS: One year of vitamin D supplementation effectively improves lean body mass, but not muscle strength and CRF in healthy adults.

Ageing affects the association between serum 25- hydroxyvitamin D concentrations and cardiorespiratory fitness in middle-aged and elderly men.

BACKGROUND AND OBJECTIVES: The studies investigated the association between serum 25-hydroxyvitamin D (25(OH)D) concentrations and cardiorespiratory fitness (CRF) are few, and the results are controversial. We aim to evaluate the association of serum 25(OH)D concentrations with CRF in adults, and assess whether the associations vary with ageing. METHODS AND STUDY DESIGN: The study included 78 middle-aged (30-64 years) and 83 elderly (65-79 years) Japanese men. Hand grip strength and leg extension power were measured using hand grip and leg dynamometers, respectively. CRF was measured via a maximal graded exercise test and quantified as the peak oxygen uptake (VO2peak). Fasting serum 25(OH)D concentrations were determined by enzyme-linked immunosorbant assay. RESULTS: Serum 25(OH)D concentrations were positively related to hand grip strength (r=0.331, p<0.001), leg extension power (r=0.353, p<0.001), CRF (r=0.285, p<0.001) in all adults after adjustment for age. Significant interaction between 25(OH)D and age on CRF was observed (p<0.05). Age-related reduction of CRF was prevented in high 25(OH)D group (p<0.05). In the elderly, subjects in high 25(OH)D group had higher CRF compared with those in low group (p<0.05). CONCLUSIONS: We found that serum 25(OH)D concentrations significantly related with leg extension power, hand grip strength and CRF after adjustment for age. The relationship of vitamin D and CRF was affected by ageing. Higher serum 25(OH)D concentrations are a key predictor for CRF in the elderly, but not in middle-aged men.

Association of Serum 25-Hydroxyvitamin D Concentrations With Glucose Profiles in Male Collegiate Football Athletes.

Low serum 25-hydroxyvitamin D [25(OH)D] concentrations are associated with a high risk of insulin resistance and Type 2 diabetes mellitus in adults. However, it is unknown whether this is the case for American collegiate football and rugby football athletes. This study investigated the associations between serum 25(OH)D concentrations and glucose profiles in male collegiate football athletes. Thirty-four collegiate athletes (13 American football players and 21 rugby football players) aged 21 years were recruited. Their body fat percent and visceral fat area were measured by dual-energy X-ray absorptiometry and magnetic resonance imaging, respectively. The participants completed an oral glucose tolerance test (75 g glucose) with venous blood samples obtained at time points 0, 30, 60, 90, and 120 min for the determination of plasma glucose and serum insulin concentrations. Fasting serum 25(OH)D concentrations were also measured. The prevalence of vitamin D deficiency and insufficiency was 17.6% and 58.8%, respectively. The serum 25(OH)D concentrations were negatively associated with the increments in the areas under the curve (iAUC) for glucose (r = -.429, p = .011) and were borderline significantly correlated with the Matsuda index (r = -.303, p = .082). No relationships were observed between the serum 25(OH)D concentrations and other glucose profiles. Multiple stepwise regression analysis of glucose iAUC concentrations as the dependent variable indicated that the serum 25(OH)D concentrations, but not body fat indicators, were independently associated with glucose iAUC (ß = -0.390, p = .025). The serum 25(OH)D concentrations were only an independent predictor for glucose iAUC in male collegiate football athletes, suggesting that increased 25(OH)D concentrations would be helpful for maintaining glucose homeostasis.

Serum 25-Hydroxyvitamin D Concentrations Are Inversely Correlated with Hepatic Lipid Content in Male Collegiate Football Athletes.

Lower serum 25-hydroxyvitamin D (25(OH)D) concentrations are associated with more weight and fat mass gain in adults in the general population, but it is unknown whether this is the case in collegiate football athletes with greater body weight. This study aimed to investigate associations of serum 25(OH)D concentrations with body fat and ectopic fat accumulation, and to determine which fat indicators are closely related to serum 25(OH)D in male collegiate football athletes. Thirty-four collegiate athletes aged 21 years were recruited. Serum 25(OH)D concentrations and the levels of visceral fat area (VFA), vastus lateralis intramyocellular lipid (IMCL), extramyocellular lipid (EMCL), and intrahepatic lipid (IHCL) were measured. Serum 25(OH)D concentrations were negatively associated with the IHCL values (r = -0.372, p = 0.030), and the relationship remained after adjustment for several factors (r = -0.378, p = 0.047). Additionally, multiple stepwise regression analysis of IHCL content as the dependent variable indicated that 25(OH)D concentrations were a stronger predictor of IHCL content (ß = -0.363, p = 0.030) than % body fat and VO2peakFFM. Higher serum 25(OH)D concentrations are more closely related to lower IHCL content rather than any other fat indicators, suggesting that increasing serum 25(OH)D concentrations may have some effect that inhibits lipid accumulation in hepatic tissue, especially in heavy athletes.

Changes in Stress and Appetite Responses in Male Power-Trained Athletes during Intensive Training Camp.

An intensive consecutive high-volume training camp may induce appetite loss in athletes. Therefore, this study aimed to investigate the changes in stress and appetite responses in male power-trained athletes during an intensive training camp. The measurements at Day 2 and at the end of a 9-day intensive training camp (Camp1 and Camp2, respectively) were compared with those of the resting period (Rest) and the regular training period (Regular; n = 13). The stress state was assessed based on plasma cortisol level, salivary immunoglobulin A level, and a profile of mood states score. The sensation of appetite was assessed using visual analog scale scores, and fasting plasma acylated ghrelin, insulin, and glucose were measured. The cortisol concentrations were significantly higher at Camp2 (466.7 ± 60.7 nmol∙L-1) than at Rest (356.3 ± 100.9 nmol∙L-1; p = 0.002) or Regular (361.7 ± 111.4 nmol∙L-1; p = 0.003). Both prospective and actual food consumption significantly decreased at Camp2, and acylated ghrelin concentration was significantly lower at Camp1 (34.2 ± 8.0 pg∙mL-1) and Camp2 (32.0 ± 8.7 pg∙mL-1) than at Rest (47.2 ± 11.2 pg∙mL-1) or Regular (53.4 ± 12.6 pg∙mL-1). Furthermore, the change in acylated ghrelin level was negatively correlated with the change in cortisol concentration. This study's findings suggest that an early-phase physiological stress response may decrease the acylated ghrelin level in male power-trained athletes during an intensive training camp.

Vitamin D supplementation reduces insulin resistance in Japanese adults: a secondary analysis of a double-blind, randomized, placebo-controlled trial.

Higher circulating 25-hydroxyvitamin D (25[OH]D) concentration has been linked to a lower prevalence of insulin resistance and type 2 diabetes mellitus. However, randomized controlled trials have not clarified the effect of vitamin D supplementation on insulin resistance in healthy adults. The objective of this study was to assess the effect of vitamin D supplementation for 1 year on insulin resistance; the study was a secondary analysis of a clinical trial. We hypothesized that increased 25(OH)D concentration after vitamin D supplementation for 1 year would significantly improve insulin resistance. Ninety-six healthy adults participated in this study, of whom 81 completed the study. The participants randomly received daily either 420 IU vitamin D3 or placebo in a double-blind manner for 1 year. The levels of fasting insulin, glucose, and other parameters were assessed at baseline and after 1 year of intervention. Homeostasis model assessment of insulin resistance index was calculated from insulin and glucose levels. Visceral fat area and physical activity were also investigated. Serum 25(OH)D and 1,25-dihydroxyvitamin D concentrations were significantly increased by approximately 29.5 nmol/L and 7.0 pg/mL, respectively, after 1-year vitamin D supplementation. After vitamin D supplementation, fasting glucose levels and values of homeostasis model assessment of insulin resistance index significantly decreased from 88.3 to 85.3 mg/dL (P < .01) and 1.17 to 0.84 (P < .01), respectively, and the results were independent of physical activity and visceral fat accumulation. In conclusion, the present study showed that vitamin D supplementation for 1 year effectively improves fasting glucose level and insulin resistance in healthy Japanese adults.

Characteristics of body composition and cardiometabolic risk of Japanese male heavyweight Judo athletes.

BACKGROUND: The purpose of this study was to clarify the characteristics of body composition and cardiometabolic risk of Japanese male heavyweight Judo athletes compared with heavyweight athletes of other sports. METHODS: Nineteen heavyweight Judo athletes (mean age, 20.4 ± 1.1 years), as well as 22 heavyweight (mean age, 21.5 ± 0.9 years) and 17 nonheavyweight (mean age, 21.1 ± 0.8 years) American football and Rugby football athletes in Japan participated in this study. Body composition was assessed by using dual-energy X-ray absorptiometry and magnetic resonance imaging. Cardiometabolic risk was evaluated by measuring blood biochemical variables. RESULTS: Heavyweight Judo athletes had significantly heavier body mass (122.7 ± 13.1 kg vs. 99.0 ± 8.1 kg), higher body fat percentage (27.5 % ± 5.2% vs. 19.4% ± 4.7%), and larger visceral fat cross-sectional area (118 ± 35 cm(2) vs. 67 ± 24 cm(2)) (P < 0.01) compared with heavyweight football players. Although the cardiometabolic risk was higher in heavyweight athletes compared to nonheavyweight athletes, there were no significant differences between heavyweight Judo and heavyweight Football athletes in the blood biochemical variables, except for high concentration of uric acid in heavyweight Judo athletes. CONCLUSIONS: Even though heavyweight Judo athletes had more excess fat mass, especially VF mass, their cardiometabolic risk in terms of blood biochemical parameters was not significantly higher compared with heavyweight athletes of other sports. Therefore, excessive fat accumulation may not necessarily increase cardiometabolic risk for heavyweight Judo athletes. TRIAL REGISTRATION: This trial is registered with the University Hospital Medical Information Network Clinical Trial Registration (UMIN-CTR) UMIN000020564.

Cardiorespiratory Fitness is a Strong Predictor of the Cardio-ankle Vascular Index in Hypertensive Middle-aged and Elderly Japanese Men.

AIM: This study aimed to examine whether cardiorespiratory fitness (CRF) is associated with arterial stiffening, evaluated using the cardio-ankle vascular index (CAVI), independent of visceral fat (VF) in middle-aged and elderly Japanese men. We also examined whether the relationship between CRF and the CAVI is modified by age and/or hypertension. METHODS: The CAVI was determined in 157 Japanese men (age range, 30-79 years), including 96 hypertensive subjects (61.1%). CRF was assessed by measuring the peak oxygen uptake (VO2peak). The subjects were divided into low- and high-CRF groups, and the VF area was assessed using magnetic resonance imaging. RESULTS: The VO2peak correlated with the CAVI following adjustment for age and body mass index in the middle-aged and elderly groups (all the subjects: r=-0.285, p＜0.001; middle-aged: r=-0.240, p=0.040; elderly: r=-0.225, p=0.049). VF also correlated with the CAVI (r=0.230, p=0.004). A multiple linear regression analysis revealed that age (ß=0.406, p<0.001) and the VO2peak (ß=-0.186, p=0.015) were associated with the CAVI independently of VF and the mean blood pressure. Two way ANCOVA adjusted for age demonstrated that the hypertensive individuals had higher CAVI values than the normotensive individuals in the low-CRF group, whereas no significant differences in the CAVI were observed in the high-CRF group (p for interaction <0.05). CONCLUSIONS: In the present study, CRF was found to be associated with the CAVI, independent of age and VF, in hypertensive middle-aged and elderly Japanese men.

Associations between the Serum 25(OH)D Concentration and Lipid Profiles in Japanese Men.

AIM: Low circulating 25-hydroxyvitamin D [25(OH)D] concentration has been linked to a high prevalence of cardiovascular disease. One explanation for this phenomenon is that there is an association between the serum 25(OH)D level and lipid profiles. However, studies examining this relationship are limited and have yielded inconsistent results. We thus aimed to evaluate the association between the serum 25(OH)D concentration and lipid profiles in Japanese men taking into consideration confounding factors, including the visceral fat area (VFA) and cardiorespiratory fitness. METHODS: A total of 136 men (age range: 20-79 years) participated in our study. Fasting blood samples were analyzed to determine the 25(OH)D, oxidized low-density lipoprotein (oxLDL), low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), triglyceride (TG), apolipoprotein (Apo)A-1 and ApoB levels. The VFA was evaluated on magnetic resonance imaging (MRI), and cardiorespiratory fitness was assessed by measuring the peak oxygen uptake (VO2 peak). RESULTS: The median 25(OH)D concentration was 35.6 nmol/L, and the prevalence of 25(OH)D deficiency was 78.7%. A multiple linear regression analysis revealed that the serum 25(OH)D concentration was inversely related to the LDL-C/HDL-C, TG, ApoB and ApoB/ApoA-1 values, even after adjusting for age, season, smoking status, alcohol consumption, medication use, vitamin D intake, calcium intake, VFA and cardiorespiratory fitness. CONCLUSIONS: Serum 25(OH)D level is inversely correlated with the LDL-C/HDL-C, TG, ApoB and ApoB/ApoA-1 values in Japanese men, independent of the VFA and cardiorespiratory fitness.

Strong influence of dietary intake and physical activity on body fatness in elderly Japanese men: age-associated loss of polygenic resistance against obesity.

Genome-wide association studies identified single nucleotide polymorphisms (SNPs) associated with body mass index (BMI) in middle-aged populations; however, it is unclear whether these SNPs are associated with body fatness in elderly people. We examined the association between genetic risk score (GRS) from BMI-associated SNPs and body fatness in elderly Japanese men. We also examined the contribution of GRS, dietary macronutrient intake, and physical activity to body fatness by different age groups. GRS was calculated from 10 BMI-associated SNPs in 84 middle-aged (30-64 years) and 97 elderly (65-79 years) Japanese men; subjects were divided into low, middle, and high GRS groups. Dietary macronutrient intake was assessed using a questionnaire, and physical activity was evaluated using both a questionnaire and an accelerometer. The middle-aged individuals with a high GRS had greater BMI; waist circumference; and total abdominal fat, visceral fat, and subcutaneous fat areas than the middle-aged individuals with low GRS, whereas the indicators were not different between the GRS groups in elderly individuals. Multiple linear regression analysis showed that GRS was the strongest predictor of BMI, total abdominal fat, and visceral fat in the middle-aged group, whereas fat, alcohol, and protein intakes or vigorous-intensity physical activity were more strongly associated with these indicators than was GRS in the elderly group. These results suggest that GRS from BMI-associated SNPs is not predictive of body fatness in elderly Japanese men. The stronger contribution of dietary macronutrient intake and physical activity to body fatness may attenuate the genetic predisposition in elderly men.

Cardiorespiratory fitness and visceral fat are key determinants of serum fibroblast growth factor 21 concentration in Japanese men.

CONTEXT: Fibroblast growth factor-21 (FGF21) is an important metabolic regulator suggested to improve glucose metabolism and prevent dyslipidemia. An FGF21-resistant state that increases circulating FGF21 has been reported in obese patients. Although regular exercise prevents metabolic disease, the relationship of the fitness level to serum FGF21 level and body fat distribution in humans remains poorly understood. OBJECTIVE: The objective of the study was to determine the relationship among the serum FGF21 concentration, cardiorespiratory fitness (CRF) level, and visceral fat area (VFA). DESIGN: Serum FGF21 was measured by an ELISA in 166 middle-aged and elderly Japanese men (aged 30-79 y) and 25 untrained and 21 endurance-trained young men (aged 19-29 y). CRF was assessed by measuring the peak oxygen uptake (VO2peak) and VFA by magnetic resonance imaging. RESULTS: In the middle-aged and elderly subjects, the serum FGF21 level correlated with the VO2peak (r = -0.355, P < .001) and VFA (r = 0.487, P < .001). Stepwise multiple regression analysis showed VFA to be most strongly associated with the serum FGF21 level (ß = .360, P < .001), and VO2peak was also an independent predictor of the serum FGF21 level (ß = -.174, P = .019). Furthermore, the proportion of subjects with an FGF21 level below the limit of detection was significantly higher among the endurance-trained than among the untrained young men (71.4% vs 24.0%, P = .001), and the VO2peak and VFA were independently associated with an undetectable FGF21 level (P < .05). CONCLUSIONS: CRF and VFA are key determinants of the circulating FGF21 concentration.

High cardiorespiratory fitness can reduce glycated hemoglobin levels regardless of polygenic risk for Type 2 diabetes mellitus in nondiabetic Japanese men.

High cardiorespiratory fitness (CRF) is associated with a reduced risk of Type 2 diabetes mellitus (T2DM) and improved ß-cell function; genetic factors also determine these risks. This cross-sectional study investigated whether CRF modifies the association of polygenic risk of T2DM with glucose metabolism in nondiabetic Japanese men. Fasting plasma glucose, insulin, and glycated hemoglobin (HbA1c) levels were measured in 174 Japanese men (age: 20-79 yr). ß-Cell function and insulin resistance were evaluated by calculating HOMA-ß and HOMA-IR, respectively. CRF was assessed by measuring maximal oxygen uptake (V̇o2max). Subjects were divided into the low and high CRF groups within each age group according to the median V̇o2max. Eleven single nucleotide polymorphisms (SNPs) associated with T2DM were analyzed and used to calculate genetic risk score (GRS); subjects were divided into the low, middle, and high GRS groups. The high GRS group had higher HbA1c levels than the low GRS group in both the low and high CRF groups (P < 0.05). Furthermore, the individuals with a high GRS had a lower HOMA-ß than those with a low GRS regardless of CRF (P < 0.05). In multiple linear regression analysis, although GRS was a significant predictor of HbA1c (ß = 0.153, P = 0.025), V̇o2max was also associated with HbA1c (ß = -0.240, P = 0.041) independent of GRS. These results suggest that CRF is associated with HbA1c levels independent of GRS derived from T2DM-related SNPs; however, it does not modify the association of GRS with increased HbA1c or impaired ß-cell function.

The relationship between serum 25-hydroxyvitamin D concentration, cardiorespiratory fitness, and insulin resistance in Japanese men.

Here, we aim to investigate the independent and combined associations of serum 25-hydroxyvitamin D (25(OH)D) and cardiorespiratory fitness (CRF) with glucose metabolism. Fasting blood samples of 107 men aged 40-79 years were analyzed for 25(OH)D, glucose, insulin, glycated hemoglobin, and lipid profile. Homeostasis model assessment of insulin resistance index (HOMA-IR) was calculated from the fasting concentrations of glucose and insulin. Visceral fat area (VFA) was determined by magnetic resonance imaging and CRF by measuring maximal oxygen uptake. Median 25(OH)D concentration was 36.3 nmol/L, while the prevalence of 25(OH)D deficiency was 74.8%. Participants with high CRF had significantly lower HOMA-IR, glycated hemoglobin, and insulin values than participants with low CRF (p < 0.05). Higher 25(OH)D concentration was strongly correlated with lower HOMA-IR and insulin values independent of VFA (p < 0.01) but significantly affected by CRF. In the high CRF group, participants with higher 25(OH)D concentration had lower HOMA-IR values than participants with low 25(OH)D concentration (p < 0.05). Higher 25(OH)D and CRF are crucial for reducing insulin resistance regardless of abdominal fat. In addition, higher 25(OH)D concentration may strengthen the effect of CRF on reducing insulin resistance in middle-aged and elderly Japanese men with high CRF.

Relative contribution of organs other than brain to resting energy expenditure is consistent among male power athletes.

We have previously shown that resting energy expenditure (REE) adjusted by fat-free mass (FFM) in male college athletes remains consistent regardless of FFM. The FFM comprises internal organs with high metabolic activity, such as liver and brain, which account for 60 to 80% of REE in adults. The purpose of the present study is to examine the contribution of internal organs to the REE of the FFM fraction among male power athletes. The study included 37 American male college football players. REE was measured by indirect calorimetry and body composition was measured by dual energy X-ray absorptiometry (DXA). Mass of brain, liver, and kidneys was measured by MRI and mass of heart was estimated by echocardiography. Normal levels of thyroid hormone (triiodothyronine: T3) were confirmed in all subjects prior to the analysis. Multiple regression analysis was used to assess the influence of FFM, fat mass (FM), T3, and mass of organs on variance of REE. Average body weight and FFM were 81.2±11.3 kg and 67.7±7.4 kg, respectively. The relative contributions of liver, kidneys, and heart to REE were consistent regardless of FFM, while the REE of brain was negatively correlated with FFM (r=-0.672, p<0.001). Only FFM and T3 were found to be independent factors influencing REE. These results suggest that a steady contribution of internal organs other than the brain is the major reason for the consistency of the REE/FFM ratio in male power athletes.

Organ size increases with weight gain in power-trained athletes.

The purpose of this study was to determine whether overfeeding and high-intensity physical training increase organ mass. We examined this question using cross-sectional and longitudinal studies in which we measured collegiate male American football players. Freshman (n = 10) and senior players in their second and third years of college (n = 17) participated in the cross-sectional study. The same measurements of the same freshman players (n = 10) were assessed after the one-year weight gain period in the longitudinal study. Fat-free mass (FFM), skeletal muscle, and adipose tissue mass were obtained using dual-energy X-ray absorptiometry. Liver, kidney, brain, and heart volumes were calculated using magnetic resonance imaging or echocardiography. Compared with the freshman players, the senior players had 10.8 kg more FFM, and 0.29 kg, 0.08 kg, and 0.09 kg greater liver, heart, and kidney mass, respectively. In the longitudinal study, FFM, liver, heart, and kidney mass of the freshman players increased by 5.2 kg, 0.2 kg, 0.04 kg, and 0.04 kg, respectively, after one year of overfeeding and physical training. On the other hand, the organ-tissue mass to FFM ratio did not change, except for the brain, in either the cross-sectional or longitudinal studies. Our results indicated that the organ-tissue masses increased with overfeeding and physical training in male collegiate American football players.

Fat-free mass can be utilized to assess resting energy expenditure for male athletes of different body size.

The fat-free mass (FFM) of athletes is typically large, and thus the FFM is often utilized to estimate their resting energy expenditure (REE). While the proportional contribution of organ-tissues to the total influence of FFM on REE is known for untrained individuals and female athletes, the extent to which this is valid for male athletes is unclear. The purpose of this study was to clarify the contribution of the components of FFM to REE in male athletes. Fifty-seven male athletes participated in this study. REE was assessed by indirect calorimetry and body composition by dual X-ray absorptiometry. The athletes were equally divided into three groups based on FFM: Small (S), Medium (M), and Large (L). When measured REE (REEm) was compared with REE estimated (REEe) based on the four organ-tissue compartments with set metabolic rates, REEm and REEe had a strong association (r=0.76, p<0.001). In addition, the absolute value of total REE became larger in accordance with body size (S: 1,643±144, M: 1,865±140, and L: 2,060±156 kcal/d) accompanied by increases in mass of all four organ-tissue compartments as body size increased. The consistency of REE/FFM in male athletes in spite of the difference in body size can be explained by the steadiness among the three groups of the relative contribution of each organ-tissue compartment to the FFM. Based on these results, the FFM is the major determinant of REE regardless of body size in male athletes.