Abstract: Background: The purpose was to develop new maximal oxygen uptake (VO2max) prediction models using a perceptually regulated 3-minute walk test. Methods: VO2max was measured with a maximal incremental cycle test in 283 Japanese adults. 3-minute walk test was conducted at a self-regulated intensity corresponding to ratings of perceived exertion (RPE) 13. Results: 3-minute walk distance (3MWD) was significantly related to VO2max (r = 0.60, p < 0.001). Three prediction models were developed by multiple regression to estimate VO2max using data on gender, age, 3MWD, and either BMI (BMI model, multiple correlation coefficients (R) = 0.78, standard error of estimate (SEE) = 5.26 ml•kg-1•min-1), waist circumference (WC model, R = 0.80, SEE = 5.04 ml•kg-1•min-1), or body fat percentage (%Fat model, R = 0.84, SEE = 4.57 ml•kg-1•min-1), suggesting that the %Fat model is the best model (VO2max = 37.501+0.463*Gender (0 = women, 1= men) - 0.195*Age - 0.589*%Fat + 0.053*3MWD). Cross-validation by using the predicted residual sum of squares (PRESS) procedures demonstrated a high level of cross-validity of all prediction models. Conclusions: The new VO2max prediction models are reasonably applicable to estimating VO2max in Japanese adults and represent a quick, low-risk, and convenient means for estimating VO2max in the field.
Abstract: Metabolic syndrome (MetS) is a complex interrelated risk factor for cardiovascular disease and type 2 diabetes mellitus. High cardiorespiratory fitness is known to contribute to prevention of MetS. However, little is known regarding the association between muscular fitness and MetS in Japanese adults. The purpose of this study was to examine the associations between muscular fitness and MetS in Japanese women and men. This cross-sectional study included 335 women and 209 men aged 30 - 79 y. MetS was determined according to the 2009 criteria of the International Diabetes Federation. Muscular fitness was evaluated by muscular fitness composite score (MFS), which was determined using Z scores from grip strength and sit-ups. Participants were classified by MFS tertile into low, middle, and high MFS groups. We used multiple logistic regression analysis to estimate odds ratios for the incidence of MetS in each group. The prevalence of MFS was 27.2% in women and 27.3% in men. Adjusted odds ratios for MetS prevalence in the low, middle, and high MFS groups, after adjusting for age, smoking status, alcohol intake, and exercise habits, were 1.0 (referent), 0.90 (95% confidence interval [CI], 0.50 - 1.62), and 0.49 (95% CI, 0.25 - 0.94; P for trend = 0.03) in women; in men, they were 1.0 (referent), 0.49 (0.23 - 1.04), and 0.42 (0.18 - 0.97; P for trend = 0.04), respectively. Muscular fitness is inversely associated with the prevalence of MetS in Japanese women and men.
Abstract: The link between cigarette smoking and predicted oxygen uptake was investigated using data for 149 Japanese men not taking medication. Cigarette smoking habits were obtained through interviews by well-trained staff. The influence of cigarette smoking on predicted oxygen uptake, predicted work rate and predicted heart rate were evaluated. Predicted oxygen uptake decreased with age. Predicted oxygen uptake and predicted work rate in men who smoked cigarettes was significantly lower than in subjects who did not, after adjusting for age. The differences in parameters did not reach significant levels after adjusting for age and physical activity evaluated by Σ[metabolic equivalents × h per week (METs?h/w)] (predicted oxygen uptake: p = 0.0632, predicted work rate: p = 0.0873). Cigarette smoking might be a modifyable factor for improving the aerobic exercise level in Japanese men.
Abstract: Purpose: To examine the associations of health-related physical fitness (HRPF) and cardiovascular disease (CVD) risk factors in Japanese women and men.
Methods: The subjects were 366 women and 162 men aged 30-79 years. Cardiorespiratory fitness (CRF) was measured with a graded exercise test on a cycle ergometer. Muscular strength was evaluated by measuring hand grip strength, muscular endurance was assessed by an abdominal endurance sit-ups test, and flexibility was measured by a sit-and-reach test. Z-scores for each test were summed to construct the HRPF index composite score (HRPFs). Various CVD risk factors, including systolic blood pressure (SBP), diastolic blood pressure (DBP), HDL cholesterol (HDL-c), triglycerides (TG), and fasting plasma glucose (FPG) were examined for each participant.
Results: After adjusting for age, body mass index (BMI), and smoking status, associations were found between CRF and SBP, DBP, HDL-c and TG, (β=−0.191; p<0.01, β=−0.167; p<0.05, β=0.245; p<0.01, β=−0.233; p<0.01, respectively), and between muscular strength and HDL-c (β=0.156; p<0.01), muscular endurance and HDL-c (β=0.121; p<0.05) in women. In men, CRF was inversely associated with TG (β=−0.255; p<0.05). Logistic regression analysis demonstrated an inverse gradient (p<0.05) across tertiles of HRPFs and individual HRPF levels (including CRF, muscular strength, and flexibility) for prevalence of having two or more CVD risk factors after adjustment for age and smoking status. In comparison with individuals in the lowest tertile of HRPFs levels, those in the middle (odds ratios (ORs) 0.32 (95% CI: 0.17 to 0.60) in women and 0.45 (95% CI: 0.20 to 1.00) in men) and highest tertile (ORs 0.12 (95% CI: 0.05 to 0.28) in women and 0.31 (95% CI: 0.13 to 0.73) in men) had a significantly lower likelihood of having two or more CVD risk factors.
Conclusions: Our results show that HRPF is associated with CVD risk factors in Japanese women and men.
Abstract: We examined whether cardiorespiratory fitness (maximal oxygen uptake, VO2max) and muscular strength (grip strength) are associated with individual and clustered metabolic risk factors independently of abdominal adiposity in Japanese men (n=110) and women (n=110) aged 20–69 years. Blood pressure, triglycerides (TG), HDL cholesterol, and fasting plasma glucose (FPG) were assessed and metabolic risk score was calculated, which is the sum of the z scores for each individual risk factor. Waist circumference was measured and the area of visceral fat was assessed by MRI. Multiple linear regression analysis revealed that VO2max was inversely associated with TG in men (p<0.05) and grip strength was negatively associated with FPG and metabolic risk score in women (p<0.001 and p<0.05, respectively), independently of waist circumference. Adjusting for visceral fat instead of waist circumference, similar results were obtained in women (p<0.01 and p<0.05, respectively), but the association between VO2max and TG in men was attenuated to nonsignificant. This cross-sectional study demonstrates that muscular strength is inversely associated with plasma glucose levels and clustered metabolic risk factors independently of abdominal adiposity in Japanese women, but not in men.
Abstract: Purpose: To investigate the use of the accelerometer-determined physical activity (PA) intensity variables as the objective PA variables for estimating V˙O2max in Japanese adult women.
Methods: The subjects of this study were 148 Japanese women aged 20 to 69 yr. Maximal oxygen uptake (V˙O2max) was measured with a maximal incremental test on a bicycle ergometer. Daily step counts (SC) and the amount spent in moderate to vigorous PA (MVPA) and vigorous PA (VPA) were measured using accelerometer-based activity monitors for 7 consecutive days. Using data of age, SC, MVPA, or VPA, and either body mass index (BMI) or waist circumference (WC), the nonexercise V˙O2max prediction models were derived as BMI modelsMVPA, WC modelsMVPA, BMI modelsVPA, and WC modelsVPA, and cross-validated by using two separate cross-validation procedures.
Results: SC, MVPA, and VPA were significantly related to V˙O2max (r = 0.43, r = 0.52, and r = 0.58, respectively). The multiple correlation coefficients for the BMI and WC modelsMVPA were 0.83 and 0.85, respectively, and for the BMI and WC modelsVPA, they were 0.85 and 0.86, respectively. The SEE was 3.3 and 3.1 mL·kg−1·min−1 for the BMI and WC modelsMVPA, respectively, and it was 3.1 and 3.0 mL·kg−1·min−1 for the BMI and WC modelsVPA, respectively. All regression models demonstrated a high level of cross-validity supported by the minor shrinkage of the coefficient of determination and the increment of SEE in the predicted residual sum of squares procedure, and by small constant errors for the subgroups of age, SC, and V˙O2max between 25 and 35 mL·kg−1·min−1.
Conclusions: This study demonstrated that multiple regression models using data of MVPA or VPA were useful in predicting V˙O2max for Japanese adult women.
Abstract: The purpose of the study was to develop a new non-exercise VO2max prediction model using a physical activity (PA) variable determined by pedometer-determined step counts (SC, steps day−1) in Japanese women aged 20–69 years old. Eighty-seven and 102 subjects were used to develop the prediction model, and to validate the new model, respectively. VO2max was measured using a maximal incremental test on a bicycle ergometer. SC was significantly related to VO2max (partial correlation coefficient r = 0.40, P < 0.001) after adjusting for BMI (kg m−2) and age (years). When the new prediction equation developed by multiple regression to estimate VO2max from age, BMI, and SC (R = 0.71, SEE = 5.3 ml kg−1 min−1, P < 0.001) was applied to the Validation group, predicted VO2max correlated well with measured VO2max (r = 0.81, P < 0.001), suggesting that SC is a useful PA variable for non-exercise prediction of VO2max in Japanese women.
Abstract: The purpose of the study was to develop new VO2max prediction models for Japanese men using a 3-minute walk test. One hundred and twenty-seven Japanese men aged from 20 to 69 years were recruited as subjects of the present study. Maximal oxygen uptake (VO2max) was measured with a maximal incremental test on a bicycle ergometer. The prediction models were derived using data of age, 3-minute walking distance (3MWD), and either BMI, waist circumference (WC), or %Fat. This data was cross-validated by using PRESS cross-validation procedures. 3MWD was significantly related to VO2max (r = 0.54, P<0.001). The multiple correlation coefficients for the BMI, WC, and %Fat models, respectively, were 0.81, 0.82, and 0.85. The standard error of estimate (SEE) was 4.5, 4.4, and 4.1 ml·kg-1·min-1, respectively, for the BMI, WC, and %Fat models. All regression models demonstrated a high level of cross-validity supported by the minor shrinkage of the coefficient of determination and increment of SEE in the PRESS procedure. This study demonstrated that 3MWD was useful for predicting VO2max accurately using VO2max prediction models for Japanese men. The new non-exercise prediction equations derived in this study are applicable to estimating VO2max in Japanese adult men.
Abstract: We assessed the maintenance of physical benefits in a 12-month exercise and nutritional intervention in postmenopausal women (55–75 years) after 6-month post-intervention follow-up by voluntary, home-based exercise, and examined whether physical factors responded differently to high or low exercise frequency during the 6-month post-intervention period. Forty-five women completed the 12-month intervention program followed by 6-month cessation of intervention, and were compared with 19 matched controls. Twenty-one of the former exercisers reported that they continued exercise training at least 30 min at least three days/week (high-frequency exerciser, HFE), while the remaining 24 former exercisers reported that they had done exercise training at least 30 min twice/week or less during the post-intervention follow-up (low-frequency exerciser, LFE). The following items were measured at baseline, 12, and 18 months: bone strength, CS-30 test, 10 m obstacle walk, whole body reaction time, one-leg stance, and grip strength. After 6-month post-intervention follow-up, the beneficial effect on the bone was not fully maintained. These benefits in physical performance obtained in the 12-month intervention program, except one-leg stance, were fully maintained for 6 months by voluntary, home-based exercise. The gained benefit in one-leg stance was not fully maintained; LFE showed a significant decrease over the 6-month post-intervention follow-up period, suggesting that continued exercise training of at least 30 min at least three days/week is required to maintain the balance benefit. These findings suggest that a continued exercise program of voluntary, home-based exercise may be effective to maintain the physical benefits of exercise intervention that may lower fracture risk in later life.
Abstract: This 1-year intervention study was designed to examine the effects of exercise and nutritional intervention on the improvement of physical factors associated with fracture risk in middle-aged and older women. One hundred twenty-six women aged 55-75 years were divided into one of 3 groups: an exercise group, an exercise and nutrition group, and a control group. Nutritional intervention was designed to encourage women to obtain sufficient daily protein (65g or over) and calcium intake (800mg or over). The setting was center-based and home-based exercise. Measurements were bone stiffness, one-leg stance, whole body reaction time, grip strength, 10m obstacle walk and 30-second chair stand. Results show that exercise intervention can significantly improve physical ability in older women with regard to one-leg stance, whole body reaction time, 10m obstacle walk and 30-second chair stand, suggesting that older women are able to ameliorate fall risk factors by exercise intervention. The exercise and nutrition group had success in modifying bone loss when compared with the exercise group, suggesting that multimodal intervention that includes exercise and nutrition targeted at correcting bone loss should be recommended. The results suggest that exercise and nutritional intervention may be an effective approach to fracture prevention in middle-aged and older women.
Abstract: This study aimed to determine if combined exercise intervention improves physical performance and gait joint-kinematics including the joint angle and dynamic range of motion (ROM) related to the risk of falling in community-dwelling elderly women. A 12-week combined exercise intervention program with extra emphasis on balance, muscle strength, and walking ability was designed to improve physical performance and gait. Twenty participants attended approximately two-hour exercise sessions twice weekly for 12 weeks. Participants underwent a physical performance battery, including static balance, sit and reach, whole body reaction time, 10 m obstacle walk, 10 m maximal walk, 30-second chair stand, to determine a physical performance score, and received quantitative gait kinematics measurements at baseline and in 12 weeks. Significant lower extremity strength improvement 13.5% (p<.001) was observed, which was accompanied by significant decreases in time of the 10 m obstacle walk (p<.05) and whole body reaction time (p<.001) in this study. However, no significant differences were seen for static balance and flexibility from baseline. For gait kinematics, in the mid-swing phase, knee and hip joint angle changed toward flexion (p<.01, p<.05, respectively). Ankle dynamic ROM significantly increased (p<.05) following exercise intervention. The plantar flexion angle of the ankle in the toe-off phase was increased significantly (p<.01). However, other gait parameters were not significantly different from baseline. These findings from the present investigation provide evidence of significant improvements in physical performance related to the risk factors of falling and safe gait strategy with a combined exercise intervention program in community-dwelling elderly women. The results suggest this exercise intervention could be an effective approach to ameliorate the risk factors for falls and to promote safer locomotion in elderly community-dwelling women.
Abstract: The purpose of this study was to determine the effects of circuit-training on heel contact velocity (HCV) during walking and reaction time (RT) in community-dwelling elderly women. Subjects were 20 healthy independent elderly women who participated in circuittraining which consisted of posture control, strength training and walking training for 12 weeks. Study outcomes included gait test, reaction time test, and 30-s chair stand test. RT and HCV were decreased significantly. The times of the 30-s chair stand test was increased significantly after training. These findings suggest that 12 weeks of circuittraining may attenuate the risks of slips and slip-initiated falls during walking in community-dwelling elderly women.
