Association of Foot Structure with the Strength of Muscles that Move the Ankle and Physical Performance.

The human foot plays an important role in supporting body weight, maintaining postural balance, and absorbing ground reaction forces. Although many studies have indicated that a causal relationship exists between foot structure and alterations in lower extremity kinematics, there is little evidence regarding the possible association of foot structure with strength of muscles that move the ankle and physical performance. A total of 67 adult men with a mean age of 51.19 ± 8.82 years participated in this study. Foot structural parameters were assessed using a 3-dimensional foot scanner. Strength of muscles that move the ankle was measured with a dynamometer. Physical performance items, including agility, force, and proprioception, were also measured. We found that all the measured parameters of the length, width, girth, and height of the foot were positively correlated with the strength of plantarflexion, dorsiflexion, eversion, and inversion (r ranged from 0.26 to 0.57; p < .05). Moreover, all or part of the parameters of the length, width, and girth of the foot but not the height and angles of the foot were correlated significantly with vertical jump, stepping forward and backward, and stepping side to side (r ranged from 0.25 to 0.44; p < .05). These findings indicate a weak-to-moderate association between foot structure and the strength of muscles that move the ankle, as well as physical performance. We therefore suggest that a larger foot may have greater muscle strength of the ankle joint and better physical performance.

Increasing Physical Activity Might Be More Effective to Improve Foot Structure and Function Than Weight Reduction in Obese Adults.

Obesity is reported to be an important factor affecting foot structure and function. For obese individuals, weight reduction or increasing weight physical activity could be an effective approach to improve foot structure and function. The present study sought to determine the effect of weight reduction and increasing physical activity on foot structure and function in obese Japanese and to investigate which intervention is more beneficial. The participants were divided into the weight reduction group (n = 30; body mass index 29.0 ± 2.5 kg/m2), with the intervention consisting of dietary modification, and the increasing physical activity group (n = 15; body mass index 28.2 ± 3.1 kg/m2), with the intervention consisting of walking and jogging. A 3-dimensional foot scanner was used to measure the foot anthropometric data with the participants both sitting and standing. The dorsum height declined and the arch stiffness index increased after the weight reduction intervention, and the truncated foot length decreased and the arch stiffness index increased after the increasing physical activity intervention (p <.05). The arch height index showed a downward trend after the weight reduction intervention (p = .060) and an upward trend after the increasing physical activity intervention (p = .069). Moreover, a greater change was found in the increase of the dorsum height and arch height index and decrease of the truncated foot length in the increasing physical activity group than in the weight reduction group (p <.05). These findings suggest that increasing physical activity might be more effective to improve foot structure and function than weight reduction in obese adults.

Mild-to-Moderate Hallux Valgus Does Not Decrease Ankle Muscle Strength in Middle-Aged Japanese Women: A Comparative Study.

Extreme hallux valgus has been documented to be related to lower functional ability and health-related quality of life. It also has a negative effect on foot structure and biomechanical characteristics, which in turn may affect muscle strength in the foot and ankle. Thus, the purposes of this study were to determine whether there is a difference of ankle muscle strength in varied hallux valgus deformities and to investigate correlations between hallux valgus angles and ankle muscle strength. Hallux valgus angles and ankle muscle strength data were collected from 31 middle-aged Japanese women. The hallux valgus angle was measured with a 3-dimensional foot scanner; ankle muscle strength was measured with a dynamometer. Results showed no differences in ankle muscle strength between normal and mild-to-moderate hallux valgus at both 60º/second and 120º/second (p > .05). Unexpectedly, women with mild-to-moderate hallux valgus had a greater value for inversion peak torque per body weight and eversion-to-inversion ratio than those with normal hallux valgus (p = .019 and p = .022) at 120º/second. Furthermore, hallux valgus was correlated with inversion peak torque and peak torque per body weight (r = 0.47; p = .012 and r = 0.50; p = .007) and associated with eversion-to-inversion strength ratio (r = -0.47; p = .012). The findings indicated that mild-to-moderate hallux valgus did not result in a decrease in ankle muscle strength. Conversely, mild-to-moderate hallux valgus had greater ankle inversion strength in middle-aged Japanese women. Further studies are needed to investigate ankle muscle strength in severe hallux valgus deformities.

Does Weight Reduction Affect Foot Structure and the Strength of the Muscles That Move the Ankle in Obese Japanese Adults?

Obesity is considered a major influential factor of foot structure and function. It has been reported to result in detrimental alterations of foot structure indicators and a decrease in muscle strength, which can lower the quality of life and increase the morbidity of obesity. The purpose of the present study was to determine the effect of weight reduction on foot structure and the strength of the muscles that move the ankle in obese adults. A total of 33 obese Japanese participants (mean body mass index 28.49 ± 2.87 kg/m2) without an exercise habit participated in a 12-week dietary modification program. Their foot structure indicators were measured using a 3-dimensional foot scanner, and the strength of the muscles that move the ankle was assessed using a dynamometer. After the dietary modification, the mean body weight reduction was 7.49 ± 4.10 kg (9.38%; 77.82 ± 13.26 kg before and 70.33 ± 11.37 kg after; p <.001). The wide foot indicators, including the forefoot girth, rearfoot width, and instep girth, had decreased significantly (p <.05), and the decreases correlated positively with the weight reduction. Regarding the strength of the muscles that move the ankle, except for dorsiflexion, all the measured peak torque values per body weight had increased significantly (p <.01). These results suggest that the weight reduction induced by a 12-week dietary modification results in thinner feet and increased strength of the muscles that move the ankle.

Effects of increasing physical activity on foot structure and ankle muscle strength in adults with obesity.

[Purpose] The purpose of this study was to examine the effects of increasing physical activity on foot structure and ankle muscle strength in adults with obesity and to verify whether the rate of change in foot structure is related to that in ankle muscle strength. [Subjects and Methods] Twenty-seven adults with obesity completed a 12-week program in which the intensity of physical activity performed was gradually increased. Physical activity was monitored using a three-axis accelerometer. Foot structure was assessed using a three-dimensional foot scanner, while ankle muscle strength was measured using a dynamometry. [Results] With the increasing physical activity, the participants' feet became thinner (the rearfoot width, instep height, and girth decreased) and the arch became higher (the arch height index increased) and stiffer (the arch stiffness index increased); the ankle muscle strength also increased after the intervention. Additionally, the changes in the arch height index and arch stiffness index were not associated with changes in ankle muscle strength. [Conclusion] Increasing physical activity may be one possible approach to improve foot structure and function in individuals with obesity.

[Effects of self-selection of dietary sessions on weight loss, dropouts during the intervention, and weight maintenance after 1 year].

OBJECTIVES: To compare the effects of weekly or bi-weekly dietary sessions with the same number of total lecture hours, periods, and lecture contents on weight loss, dropouts during the intervention, and the weight loss maintenance after 1 year. METHODS: The study included 52 middle-aged women with at least 1 risk factor for cardiovascular disease (i.e., obesity, hypertension, dyslipidemia, and hyperglycemia) who were encouraged to lose weight. Thirty-seven women were assigned to the weekly class (self-selected weekly class group: n=26) or the bi-weekly class (self-selected bi-weekly class group: n=11) based on their preference. Fifteen women were assigned to the bi-weekly class against their will (bi-weekly class group). All groups participated in the same number of sessions (total, 26 h), and were instructed to reduce their dietary intakes to 1200 kcal/day for 13 weeks. The self-selected weekly class group attended a 2-h instructional session every week, whereas both the bi-weekly class groups received 1-h sessions twice a week. Data on the body weight of the participants was collected 1 year after the intervention using a self-administered questionnaire via mail. RESULTS: The self-selected bi-weekly class group had significantly fewer dropouts (self-selected weekly class group: 5 persons, 19.2%; self-selected bi-weekly class group: 1 person, 9.0%; bi-weekly class group: 8 persons, 53.3%; P<0.05). There was a significant decrease in weight (P<0.05) in all 3 groups during the intervention (self-selected weekly class group: -4.3±2.7 kg, self-selected bi-weekly class group: -6.7±3.0 kg, bi-weekly class group: -6.0±3.4 kg). However, weight loss in the self-selected bi-weekly class group was significantly greater than that in the other 2 groups. A significant change in body weight at the 1-year follow-up was not observed in any group (self-selected weekly class group: +0.4±1.3 kg, self-selected bi-weekly class group: -0.1±2.3 kg, bi-weekly class group: +0.5±0.6 kg). Repeated-measures ANOVA (time×group) revealed no significant interactions in weight loss. CONCLUSION: These results suggest that a greater frequency of dietary sessions contributes to weight loss, while a lesser frequency of dietary sessions contributed to a decrease in questionnaire recovery rates. The dropout rate in the self-selected weekly and bi-weekly class groups was lesser than that in the bi-weekly class group. Therefore, dietary sessions tailored to the needs of the participants might decrease the dropout rate.

Response of coronary heart disease risk factors to changes in body fat during diet-induced weight reduction in Japanese obese men: A pilot study.

OBJECTIVE: Serial measurements were used to examine the response of coronary heart disease (CHD) risk factors to regional fat changes during weight reduction. METHODS: Nine Japanese obese men participated in a diet-induced weight loss program. Regional fat masses, abdominal visceral fat area (VFA), subcutaneous fat area (SFA) and CHD risk factors, including total (TC), high (HDLC)- and low-density lipoprotein cholesterol (LDLC), triglycerides (TG), fasting plasma glucose, immunoreactive insulin, homeostasis model assessment of insulin resistance (HOMA-IR), and glycosylated hemoglobin A(1c) (HbA(1c)) were assessed at baseline and after 1, 2 and 3 months. RESULTS: Meanweight reduction during the study was -11.9 +/- 4.2 kg, which was associated with a gradual, significant decrease (p < 0.05) in arm, leg and trunk fat masses, VFA and SFA. The levels of TC, LDLC and TG decreased significantly within 1 month and remained at these values, whereas HDLC, HOMA-IR, and HbA(1c) did not change. There was no significant correlation between changes in regional fat masses and CHD risk factors in any period studied. CONCLUSIONS: CHD risk factors do not necessarily respond in the same manner as changes in body fat during diet-induced moderate weight reduction.

Association of abdominal fat with metabolic syndrome components in overweight women: effect of menopausal status.

BACKGROUND: The association between abdominal fat distribution and metabolic syndrome (MetSyn) components by menopausal status has yet to be explicated. The purpose of this study was to examine a cross-sectional association between abdominal fat compartments and MetSyn components in pre- and post-menopausal overweight Japanese women. METHODS: Of 212 overweight Japanese women, 76 pre-menopausal overweight (BMI ≥ 25) women (PreM age, 42.1 ± 5.9 years) and 87 post-menopausal overweight women (PostM: age, 56.2 ± 4.5 years) were analyzed in this study. Measurements were taken for body mass index (BMI), abdominal compartments [visceral fat (VF), subcutaneous fat (SF), superficial subcutaneous fat (SSF), and deep subcutaneous fat (DSF)], serum high-density lipoprotein cholesterol (HDLC), low-density lipoprotein cholesterol, triglycerides (TG), and fasting plasma glucose (FPG). Abdominal compartments were assessed using computed tomography. RESULTS: No significant differences were found for BMI, SF, SSF, or DSF between the PreM and PostM. Despite this, the PreM had a significantly smaller VF area than that of the PostM. However, the difference in VF area disappeared when age was adjusted for. VFA significantly correlated with HDLC, TG, and FPG independently of menopause status. CONCLUSIONS: These results suggest that the effect of menopause status on the association between VF and MetSyn components is negligible. Abdominal subcutaneous fat compartments were not associated with MetSyn components in overweight women regardless of menopausal status.

Impact of weight reduction on production of platelet-derived microparticles and fibrinolytic parameters in obesity.

INTRODUCTION: Generation of platelet-derived microparticle (PMP) is implicated in cardiovascular disease (CVD). However, the influence of adiposity and weight reduction on PMP generation remains to be fully elucidated. We compared PMP generation and fibrinolytic parameters between 49 non-diabetic obese (obese group) and 37 age-matched non-obese subjects (control group), and compared the effects of weight reduction on the parameters between a 12-week calorie restricted diet and diet with aerobic exercise in obese subjects. MATERIALS AND METHODS: PMP, plasma levels of plasminogen activator inhibitor-1 (PAI-1) activity and tissue-type plasminogen activator (t-PA) antigen were measured before and after intervention. RESULTS: Before intervention, PMP, PAI-1 activity and t-PA antigen values were elevated in the obese group compared with the control group. In all 86 subjects of both groups, these three parameters correlated with body mass index, waist circumference and fat tissue mass. There was a positive correlation between plasma levels of fibrinolytic parameters and visceral fat area (VFA). PMP values correlated with subcutaneous fat area (SFA). The intervention significantly reduced PMP, PAI-1 activity and t-PA antigen levels. There was a significant correlation between percentages of changes in PMP values and those in BMI, fat tissue mass and VFA in the obese group. No additional effect of exercise on PMP or fibrinolytic parameters was observed. CONCLUSIONS: Overproduction of PMP and fibrinolytic abnormalities may be associated with excessive adipose tissue. Weight reduction by either calorie restriction with or without exercise improves fibrinolytic abnormalities and PMP overproduction, probably through reduction of adipose tissue.

Effects of diet with or without exercise on leptin and anticoagulation proteins levels in obesity.

Obesity is a risk factor for cardiovascular disease and thromboembolic events. We investigated the effects of weight reduction by a 12-week calorie-restricted diet with or without aerobic exercise (diet group and diet plus exercise group) on leptin and anticoagulation proteins levels. Forty-two obese nondiabetic individuals were evaluated for blood levels of leptin, protein C activity, free protein S antigen and for body fat area calculated on computerized tomography before and after intervention. Before intervention, serum levels of leptin and free protein S antigen correlated positively with several adiposity-related parameters. After the program, body weight and fat area were significantly decreased in both groups. Body mass index and leptin levels decreased in both groups, with a larger change in the diet plus exercise group than in the diet group. Although protein C activity levels did not change in both groups, free protein S antigen levels decreased significantly in the diet plus exercise group. In conclusion, the 12-week programs had significant effects on the initial weight reduction and body fat mass, decreasing lepin levels in obese nondiabetic individuals. To clarify whether aerobic exercise has additional or direct effects on the anticoagulation system, a study in a large number of individuals is needed.

Characteristics of foot morphology and their relationship to gender, age, body mass index and bilateral asymmetry in Japanese adults.

BACKGROUND: Different characteristics of foot morphology are commonly accompanied by altering lower extremity biomechanical characteristics and foot function. Clarifying what factors affect foot morphology is helpful in understanding the basis of foot deformity and foot dysfunction. OBJECTIVE: The aim of this study was to investigate characteristics of foot morphology and whether related factors such as gender, age, body mass index (BMI) and bilateral asymmetry have an impact on foot morphology. METHODS: One hundred and eighty adults without exercise habit were included in this cross-sectional study. Participants were categorized by gender, age, BMI, and left and right foot respectively to compare foot morphology differences. The characteristics of foot morphology were measured using a 3D foot scanner. RESULTS: Compared with females, males had longer, larger and higher feet. In terms of age differences, older adults had shorter and stiffer feet. Regarding BMI differences, the value of height and width parameters of foot was larger, and the value of height of arch also larger in those with greater BMI. Regarding bilateral asymmetry, the right foot had a higher foot than the left foot. Multiple linear regression models indicated that gender, age and BMI significantly affected length and girth parameters of foot together. CONCLUSIONS: This study showed that gender has a bigger impact on length, width, height and girth parameters of foot than BMI or age. BMI has an impact on both arch height and stiffness. Besides, bilateral asymmetry affects values of height parameters of foot and arch.

Evaluation of blood rheology in patients with cyanotic congenital heart disease using a microchannel array flow analyzer.

Blood hyperviscosity due to secondary erythrocytosis is a common pathologic feature of cyanotic congenital heart disease (CCHD). In CCHD, it is possible that hematological parameters other than red blood cells influence blood rheology. We measured blood passage time to evaluate the blood rheology in patients with CCHD (n=18, age: 15.3+/-11.9 years, mean +/- SD) and age-matched control subjects (n=27) using the microchannel array flow analyzer (MC-FAN), and the results [several hematological parameters, including hematocrit (Hct)] were compared. Blood passage time in the CCHD group was prolonged, compared with the control group (67.6+/-27.2 s vs. 44.6+/-6.7 s). For the CCHD group, blood passage time correlated significantly with red blood cell (RBC) count, hemoglobin (Hb) concentration, Hct, mean corpuscular hemoglobin concentration (MCHC), platelet (Plt) count, high-density lipoprotein cholesterol (HDL-C) level, and triglycerides (TG) level (RBC, r=0.77; Hb, r=0.69; Hct, r=0.73; MCHC, r=-0.64; Plt, r=-0.49; TG, r=0.53; HDL-C, r=-0.49, p<0.05 for each variable). For all 45 subjects, blood passage time correlated significantly with HbA1c level (r=0.45, p<0.01) and tissue-type plasminogen activator (t-PA) antigen level (r=0.46, p<0.01). Our results indicated that blood rheology is reduced in patients with CCHD as expressed by prolonged blood passage time, and it may be defined by several blood parameters in addition to erythrocytosis.

Significant associations among hemostatic parameters, adipokines, and components of the metabolic syndrome in Japanese preschool children.

Development of cardiovascular diseases could originate in early childhood. However, reference values of hemostatic parameters and adipokines in preschool children remain to be explored. We measured blood levels of adipokines and parameters of the hemostatic/fibrinolytic systems in 167 healthy children aged 4 to 6 years at 9:00 to 10:30 am after a strictly enforced overnight fast. Participants with body mass index (BMI) values ≥90th percentile had significantly higher values of systolic blood pressure and heart rate, as well as blood levels of insulin, coagulation factor (F) VII, FX, protein S, leptin, and homeostasis model assessment of insulin resistance (HOMA-IR), and lower values of desacyl-ghrelin than children with BMI < 90th percentile. Circulating levels of fibrinogen and leptin increased with increased number of cardiovascular risk factors. Stepwise regression analysis identified many hematological variables to be associated with features of the metabolic syndrome. The results implicated the hemostatic/fibrinolytic system or adipokines in the insidious progression of cardiovascular diseases from an early age.

Influence of acute aerobic exercise on adiponectin oligomer concentrations in middle-aged abdominally obese men.

Exercise intensity may induce changes in total adiponectin and adiponectin oligomer levels. However, the effects of acute aerobic exercise on total adiponectin and adiponectin oligomers in middle-aged abdominally obese men remain unknown. The purpose of this study was to investigate the influence of aerobic exercise intensity on changes in the concentrations of total adiponectin and adiponectin oligomers (high-molecular weight [HMW] and middle- plus low-molecular weight [MLMW] adiponectin), and the endocrine mechanisms involved in exercise-induced changes in adiponectin oligomer profiles in middle-aged abdominally obese men. Using a crossover design, 9 middle-aged abdominally obese men (age, 54.1 ± 2.4 years; body mass index, 27.9 ± 0.6 kg/m²) underwent 2 trials that consisted of 60 minutes of stationary cycle exercise at either moderate-intensity (ME) or high-intensity (HE) aerobic exercise (50% or 70% of peak oxygen uptake, respectively). Blood samples were collected to measure the concentrations of adiponectin oligomers, hormones (catecholamines, insulin, and growth hormone), metabolites (free fatty acid, glycerol, triglyceride, and glucose), and cytokines (interleukin-6 and tumor necrosis factor-α). After exercise, plasma catecholamine concentrations were higher during HE than during ME (P < .05). Total adiponectin concentration decreased at the end of HE (P < .05), but remained unchanged after ME. The HMW adiponectin concentration did not change at either intensity, whereas the MLMW concentration decreased at the end of HE (P < .05). The ratio of HMW to total adiponectin concentration increased significantly (P < .05), whereas the ratio of MLMW to total adiponectin concentration decreased significantly (P < .05), at the end of HE. The percentage changes in epinephrine concentration from baseline to the end of exercise were correlated with the percentage changes in total adiponectin concentration (r = -0.67, P < .05) and MLMW adiponectin concentration (r = -0.82, P < .05) from baseline to the end of HE. Our results indicate that the change in total adiponectin was mainly due to a change in MLMW adiponectin concentration during high-intensity exercise in middle-aged abdominally obese men. Epinephrine may partially regulate the decrease in total and MLMW adiponectin concentrations during high-intensity exercise.

Determinants of blood rheology in healthy adults and children using the microchannel array flow analyzer.

PURPOSE: The reference values of blood rheology in healthy participants, especially children, are not available. The purpose of this study was to determine the blood passage time (BPT) as an index of blood rheology, in healthy children and adults, using the microchannel array flow analyzer, and to investigate the hematological factors that define BPT. METHODS: Participants were 61 healthy children (35 boys, 26 girls; age 5-6 years) and 71 healthy adults (24 men, age 35.2 +/- 14.1 years; 47 women, age 44.7 +/- 14.1 years, mean +/- standard deviation [SD]). Blood passage time and various hematological variables (blood cell count, serum lipids, and fibrinogen) were measured and compared among the 4 study groups. RESULTS: Blood passage time values were significantly higher in adult men (48.8 +/- 5.8 seconds) than in boys (41.9 +/- 4.0 seconds), girls (43.7 +/- 7.8 seconds), and adult women (42.4 +/- 4.8 seconds). Stepwise regression analysis identified erythrocyte count and hemoglobin (Hb) as the significant and independent determinants of BPT (P < .05). CONCLUSION: Our study demonstrates that BPT is significantly longer in healthy adult men than in adult women and children, and that erythrocyte count and Hb are significant determinants of blood rheology.

The effects of vigorous physical activity on intra-abdominal fat levels: a preliminary study of middle-aged Japanese men.

AIM: To examine the effects of vigorous physical activity (PA) on intra-abdominal fat (IF) levels in obese men. METHODS: Thirty-seven obese men (mean age: 47.6+/-8.6 years) engaged in a 12-week aerobic exercise program on a regular basis (3 days/week). We divided them into low volume of vigorous PA group (n=19) or high volume of vigorous PA group (n=18), based on the median time spent (34.3min/week) in vigorous PA (over 6.1 metabolic equivalents assessed by a single-axis accelerometer) throughout the program. RESULTS: Regular exercise reduced IF levels (measured by computed tomography) from 188.1+/-53.9cm(2) to 170.3+/-46.6cm(2) for the low volume of vigorous PA group and from 167.9+/-44.3cm(2) to 137.9+/-40.6cm(2) for the high volume of vigorous PA group. Two-way (time x group) ANOVA revealed no significant interactions for the IF level. However, correlation analysis for all participants showed that time spent in vigorous PA throughout the program significantly correlated to IF reductions after adjusting for initial levels of IF, vigorous PA and weight changes (r=-0.42, P=0.02). CONCLUSION: This study suggests that vigorous PA may affect IF reductions in obese men.

Air displacement plethysmography for estimating body composition changes with weight loss in middle-aged Japanese men.

AIM: To examine the degree to which air displacement plethysmography (ADP) can track body composition changes in response to weight loss in obese Japanese men. METHOD: 50 men, aged 30-65 years with a mean BMI of 30 kg/m(2), were included in a 3-month weight loss program. Percentage of fat mass (%FM) was determined by dual energy X-ray absorptiometry (DXA) and ADP at baseline and month 3. RESULTS: With 6.2 ± 4.3 kg of weight loss, %FM, as determined by DXA and ADP, significantly decreased by 3.9 ± 2.9% and 3.9 ± 3.3% respectively. There was no mean difference for change (Δ) in %FM between the two methods. DXA-derived Δ%FM significantly correlated with Δ%FM determined by ADP (R(2) = 0.48, p < 0.01). Furthermore, the Bland-Altman plots demonstrated no systematic bias for Δ%FM (r = -0.20, p = 0.17). However, %FM by ADP (r = 0.42) at baseline and Δ%FM by ADP (r = -0.54) were significantly correlated to the differences between Δ%FM by DXA and ADP. CONCLUSION: These results suggest that ADP is comparably accurate for evaluating Δ%FM when compared with DXA, although there were proportional biases.

Obesity phenotype and intra-abdominal fat responses to regular aerobic exercise.

AIM: To examine the effects of obesity phenotype on abdominal fat responses to regular aerobic exercise. METHOD: Fifty-seven obese men aged 34-70 years were divided into two groups based on baseline intra-abdominal fat (IF) area measured by computerized tomography: moderate (<200 cm(2)) IF (MIF; n=33, age: 52.9+/-10.6 [SD] yr, body mass index [BMI]: 29.2+/-3.1 kg/m(2)) or high (>or=200 cm(2)) IF (HIF; n=24, age: 53.5+/-9.5 yr, BMI: 30.3+/-3.1 kg/m(2)). The 12-week exercise program consisted primarily of aerobic exercise and met 3 days per week for 90 min per session. Weight, BMI, body composition (by dual-energy X-ray absorptiometry), IF and subcutaneous fat (SF) areas were measured before and after the program. RESULTS: Regular aerobic exercise reduced weight by 2.3+/-2.2 kg in MIF and 3.2+/-3.0 kg in HIF. HIF reduced significantly more IF area than MIF (15.1+/-26.0 cm(2) in MIF and 43.3+/-41.9 cm(2) in HIF), and the difference remained significant after adjusting for baseline fat mass, weight change and total energy intake during the 12-week aerobic exercise. CONCLUSION: Exercise-induced IF reduction may be remarkably influenced by obesity phenotype.

Sex differences in substrate oxidation during aerobic exercise in obese men and postmenopausal obese women.

The aim of this study was to compare substrate oxidation during aerobic exercise in obese men and postmenopausal obese women. Ten obese men (mean age, 55.4 +/- 2.2 years; body mass index, 27.5 +/- 0.4 kg/m(2); peak oxygen uptake [Vo(2)peak], 44.4 +/- 1.9 mL/kg fat-free mass/min; mean +/- SE] and 10 postmenopausal obese women (mean age, 57.2 +/- 1.2 years; body mass index, 27.9 +/- 0.5 kg/m(2); VO(2)peak, 39.9 +/- 1.3 mL/kg fat-free mass/min) performed a 40-minute bout of cycling exercise at 50% VO(2)peak. Blood samples were collected for assessment of metabolic variables and 17beta-estradiol concentration at baseline and during aerobic exercise. Breath samples were collected to estimate carbohydrate and fat oxidation using a digital computer-based breath-by-breath exercise analysis system during aerobic exercise. Serum 17beta-estradiol concentration was not significantly different between the men and women subjects at baseline (P > .05). Serum free fatty acid concentration tended to be higher in the men than in the women (P = .07) during the exercise, but the respiratory exchange ratio during exercise was lower in women than in men (P < .05). Fat oxidation adjusted for fat-free mass was higher (P < .05) in women than in men. These results suggest that fat utilization was higher during aerobic exercise in postmenopausal obese women than in obese men and did not depend on resting serum 17beta-estradiol concentration.