Yoshitake Oshima

Classifying household and locomotive activities using a triaxial accelerometer.

The purpose of this study was to develop a new algorithm for classifying physical activity into either locomotive or household activities using a triaxial accelerometer. Sixty-six volunteers (31 men and 35 women) participated in this study and were separated randomly into validation and cross-validation groups. All subjects performed 12 physical activities (personal computer work, laundry, dishwashing, moving a small load, vacuuming, slow walking, normal walking, brisk walking, normal walking while carrying a bag, jogging, ascending stairs and descending stairs) while wearing a triaxial accelerometer in a controlled laboratory setting. Each of the three signals from the triaxial accelerometer was passed through a second-order Butterworth high-pass filter to remove the gravitational acceleration component from the signal. The cut-off frequency was set at 0.7 Hz based on frequency analysis of the movements conducted. The ratios of unfiltered to filtered total acceleration (TAU/TAF) and filtered vertical to horizontal acceleration (VAF/HAF) were calculated to determine the cut-off value for classification of household and locomotive activities. When the TAU/TAF discrimination cut-off value derived from the validation group was applied to the cross-validation group, the average percentage of correct discrimination was 98.7%. When the VAF/HAF value similarly derived was applied to the cross-validation group, there was relatively high accuracy but the lowest percentage of correct discrimination was 63.6% (moving a small load). These findings suggest that our new algorithm using the TAU/TAF cut-off value can accurately classify household and locomotive activities.

Real-time estimation of daily physical activity intensity by a triaxial accelerometer and a gravity-removal classification algorithm.

We have recently developed a simple algorithm for the classification of household and locomotive activities using the ratio of unfiltered to filtered synthetic acceleration (gravity-removal physical activity classification algorithm, GRPACA) measured by a triaxial accelerometer. The purpose of the present study was to develop a new model for the immediate estimation of daily physical activity intensities using a triaxial accelerometer. A total of sixty-six subjects were randomly assigned into validation (n 44) and cross-validation (n 22) groups. All subjects performed fourteen activities while wearing a triaxial accelerometer in a controlled laboratory setting. During each activity, energy expenditure was measured by indirect calorimetry, and physical activity intensities were expressed as metabolic equivalents (MET). The validation group displayed strong relationships between measured MET and filtered synthetic accelerations for household (r 0·907, P < 0·001) and locomotive (r 0·961, P < 0·001) activities. In the cross-validation group, two GRPACA-based linear regression models provided highly accurate MET estimation for household and locomotive activities. Results were similar when equations were developed by non-linear regression or sex-specific linear or non-linear regressions. Sedentary activities were also accurately estimated by the specific linear regression classified from other activity counts. Therefore, the use of a triaxial accelerometer in combination with a GRPACA permits more accurate and immediate estimation of daily physical activity intensities, compared with previously reported cut-off classification models. This method may be useful for field investigations as well as for self-monitoring by general users.

A Simple Measurement Method of Visceral Fat Accumulation by Bioelectrical Impedance Analysis

Simple measurement of visceral fat accumulation is essential for diagnosis and treatment of metabolic syndrome. Bioelectrical impedance method is most suitable for theses measurements. However, measuring visceral fat volume without the influence of subcutaneous fat has been difficult because of the low spatial resolution of bioelectrical impedance method. In the present study, we have developed a simple method for the measurement of visceral fat accumulation using visceral fat bioelectrical impedance analysis (VF-BIA). For VF-BIA, an electric current (250 μA, 50 kHz) was applied to electrodes bilaterally fixed on the hands and feet, and the voltage was measured between six pairs of electrodes placed around the trunk at the umbilical level. The impedance reflects the total amount of abdomen fat, in addition to obtain the impedance of the body surface which reflects the amount of subcutaneous fat, the voltage induced by applying electric current to the electrodes placed on the body surface around the trunk at the umbilical level was measured with electrodes between the stimulating electrodes. Regarding to measure these two impedance values we adopted the four electrodes method.

A new simple measurement system of visceral fat accumulation by bioelectrical impedance analysis

Measurement of visceral fat accumulation is essential for the diagnosis of obesity. Currently, the visceral fat area (VFA) obtained from the abdominal cross-sectional image measured by X-ray CT is used as the gold standard. However it has problems of complexity, cost, and X-ray exposure. On the other hand, the waist circumference is used as a simple index, but it is indirect method and is affected by subcutaneous fat. Bioelectrical impedance analysis (BIA) is a proven method practically used to measure total body fat, and is the most suitable for the measurement of visceral fat accumulation. For the latter purpose, we developed a new simple measurement system using dual current pathways bioelectrical impedance analysis (dual-BIA). This proposed system measures imped ance reflecting the subcutaneous fat volume (SFV) and the fat free volume (FFV) in the abdomen by passing current via respective pathways. Regarding to measure these two imped ance values we adopted the four electrodes method. The VFA was calculated by using these two impedance values and abdominal body shape data to minimize the influence of FFV and SFV. We compared the VFA measured by dual-BIA system with that measured by X-ray CT in 98 subjects, and found a high correlation coefficient (r=0.888, p<0.001). Our proposed system is suggested to be useful for a simple visceral fat accumulation measurement.

Prediction models discriminating between nonlocomotive and locomotive activities in children using a triaxial accelerometer with a gravity-removal physical activity classification algorithm.

The aims of our study were to examine whether a gravity-removal physical activity classification algorithm (GRPACA) is applicable for discrimination between nonlocomotive and locomotive activities for various physical activities (PAs) of children and to prove that this approach improves the estimation accuracy of a prediction model for children using an accelerometer. Japanese children (42 boys and 26 girls) attending primary school were invited to participate in this study. We used a triaxial accelerometer with a sampling interval of 32 Hz and within a measurement range of ±6 G. Participants were asked to perform 6 nonlocomotive and 5 locomotive activities. We measured raw synthetic acceleration with the triaxial accelerometer and monitored oxygen consumption and carbon dioxide production during each activity with the Douglas bag method. In addition, the resting metabolic rate (RMR) was measured with the subject sitting on a chair to calculate metabolic equivalents (METs). When the ratio of unfiltered synthetic acceleration (USA) and filtered synthetic acceleration (FSA) was 1.12, the rate of correct discrimination between nonlocomotive and locomotive activities was excellent, at 99.1% on average. As a result, a strong linear relationship was found for both nonlocomotive (METs = 0.013×synthetic acceleration +1.220, R2 = 0.772) and locomotive (METs = 0.005×synthetic acceleration +0.944, R2 = 0.880) activities, except for climbing down and up. The mean differences between the values predicted by our model and measured METs were −0.50 to 0.23 for moderate to vigorous intensity (>3.5 METs) PAs like running, ball throwing and washing the floor, which were regarded as unpredictable PAs. In addition, the difference was within 0.25 METs for sedentary to mild moderate PAs (<3.5 METs). Our specific calibration model that discriminates between nonlocomotive and locomotive activities for children can be useful to evaluate the sedentary to vigorous PAs intensity of both nonlocomotive and locomotive activities.

Effect of weight-loss program using self-weighing twice a day and feedback in overweight and obese subject: A randomized controlled trial

OBJECTIVE To investigate the effectiveness of self-weighing twice a day with a supportive program installed on a body composition monitor in overweight adults. SUBJECTS Sixty adults with BMI > 24 kg/m(2) were randomly assigned to either a group that weighed themselves once per day (group 1, n = 30) or a group that weighed themselves twice per day (group 2, n = 30). INTERVENTION Group 1 was instructed to self-weigh at the same time once per day and group 2 was instructed to self-weigh immediately after waking up in the morning and immediately before going to bed every day for twelve weeks. In addition, participants in group 2 was received the daily target setting during morning weighing and the difference between the measured weight and the target weight during bedtime weighing. RESULTS Average weight reduction in group 1 was significantly lower than that in group 2 (1.0 ± 1.4 kg vs. 2.7 ± 2.1 kg, p < 0.05). The proportion of participants who lost ≥ 5% of their pre-program weight in group 2 was significantly higher than that in group 1 (28.6% vs. 3.6%, p < 0.05). CONCLUSION A self-weighing twice per day plus daily target setting and feedback is more effective in promoting weight loss than once-daily self-measurement.

Estimation of whole-body skeletal muscle mass by bioelectrical impedance analysis in the standing position.

Summary Objective To develop a clinical method for evaluating skeletal muscle (SM) mass using whole-body bioelectrical impedance (BI) analysis in the standing position. Subjects Two hundred and forty-four volunteers (men=106 and women=138) participated in this study. The subjects were randomly separated into validation and cross-validation groups. Methods The whole-body impedance ( Z ) between the hands and feet was measured in the standing position. A stepwise multiple regression analysis was used to develop the prediction equation for SM mass. Whole-body SM mass, measured by magnetic resonance imaging (MRI), was used as a reference. Results BI index (height 2 / Z ), body surface area (BSA), gender, and age were selected as significant contributors to predict SM in the validation group. There was no significant difference between the measured and estimated SM mass and no systematic error in BI analysis in the cross-validation group. All data were pooled to generate the final regression equation: SM mass \( kg \) = \( 0.126 × BI index \) + \( 1.937 × BSA \) + \( − 0.062 × age \) + \( − 2.186 × gender \) − 2.881 , where age is in years. Gender for men=1 and women=2. Analysis revealed that the slope and intercept were not significantly different from one and zero, respectively. The r 2 and SEE values of the regression equation were 0.893 and 1.65kg, respectively. Conclusions Using our developed prediction equation, the BIA system can be used to accurately evaluate whole-body skeletal muscle mass with the subject in the standing position.

Validity and reproducibility of a novel method for time-course evaluation of diet-induced thermogenesis in a respiratory chamber.

We developed a novel method for computing diet‐induced thermogenesis (DIT) in a respiratory chamber and evaluated the validity and reproducibility of the method. We hypothesized that DIT may be calculated as the difference between postprandial energy expenditure (EE) and estimated EE (sum of basal metabolic rate and physical activity (PA)‐related EE). The estimated EE was derived from the regression equation between EE from respiration and PA intensity in the fasting state. It may be possible to evaluate the time course of DIT using this novel technique. In a validity study, we examined whether DIT became zero (theoretical value) for 6 h of fasting in 11 subjects. The mean value of DIT calculated by the novel and traditional methods was 22.4 ± 13.4 and 3.4 ± 31.8 kcal/6 h, respectively. In the reproducibility study, 15 adult subjects lived in the respiratory chamber for over 24 h on two occasions. The DIT over 15 h of postprandial wake time was calculated. There were no significant differences in the mean values of DIT between the two test days. The within‐subject day‐to‐day coefficient of variation for calculated DIT with the novel and traditional methods was approximately 35% and 25%, respectively. The novel method did not have superior reproducibility compared with that of the traditional method. However when comparing the smaller variation in the fasting state than the theoretical value (zero), the novel method may be better for evaluating interindividual differences in DIT than the traditional method and also has the ability to evaluate the time‐course.

Effects of telephone-delivered lifestyle support on the development of diabetes in participants at high risk of type 2 diabetes: J-DOIT1, a pragmatic cluster randomised trial

Objectives To examine the effects of telephone-delivered lifestyle coaching on preventing the development of type 2 diabetes mellitus (T2DM) in participants with impaired fasting glucose (IFG). Design Cluster randomised trial. Setting 40 groups from 17 healthcare divisions in Japan: companies (31), communities (6) and mixed settings (3). Participants Participants aged 20–65 years with fasting plasma glucose (FPG) of 5.6–6.9 mmol/L were invited from the 17 healthcare divisions. Randomisation The groups were then randomly assigned to an intervention or a control arm by independent statisticians according to a computer-generated list. Intervention The intervention arm received a 1-year telephone-delivered intervention provided by three private lifestyle support centres (at different frequencies: low-frequency (3 times), middle-frequency (6 times) and high-frequency (10 times) support calls). The intervention and control arms both received self-help devices such as a weight scale and pedometer. Outcomes Participants were followed up using data from annual health check-ups and a questionnaire regarding lifestyle. The primary outcome was the development of T2DM defined as FPG ≥7.0 mmol/L, the diagnosis of diabetes, or use of an antidiabetic drug, confirmed by referring to medical cards. Results Of 14 473 screened individuals, participants were enrolled in either the intervention (n=1240) arm or control (n=1367) arm. Overall, the HR for the development of T2DM in the intervention arm during 5.5 years was 1.00 (95% CI 0.74 to 1.34). In the subanalysis, the HR was 0.59 (95% CI 0.42 to 0.83) in the subgroup that received phone calls the most frequently, compared with the control arm. A limitation of the study includes a lack of blinding. Conclusions High-frequency telephone-delivered lifestyle support could effectively prevent T2DM in participants with IFG in a primary healthcare setting, although low-frequency and middle-frequency phone calls did not. Trial registration number This trial has been registered with the University Hospital Medical Information Network (UMIN000000662).

Non-locomotive physical activity intervention using a tri-axial accelerometer reduces sedentary time in type 2 diabetes

ABSTRACT Objectives: The purpose of this study is to examine whether the use of a tri-axial accelerometer can reduce sedentary time and increase non-locomotive physical activity (N-LPA), and to investigate the effect of this intervention on parameters of glucose and fat metabolism in patients with type 2 diabetes. Methods: Thirty-eight patients with type 2 diabetes (Age: 61.8 ± 1.4 years, BMI: 24.8 ± 0.6, HbA1c: 6.6 ± 0.1 %) participated in this 12-week randomized controlled study, and 31 patients were included in the final analyses. Patients were randomly assigned to one of three groups: control, N-LPA or locomotive physical activity (LPA). Patients in the N-LPA and LPA groups were asked to increase their N-LPA and LPA, respectively, using tri-axial accelerometer feedback. Glucose and fat metabolic parameters were evaluated before and after 12-week intervention. Results: Only the N-LPA intervention significantly reduced sedentary time (p < 0.05) and increased N-LPA (p < 0.05). However, these changes were insufficient to improve parameters associated with glucose and fat metabolism (p > 0.05), despite a significant positive correlation between the change in sedentary time and HbA1c levels (p < 0.05). Conclusion: Our results showed that the N-LPA intervention using a tri-axial accelerometer successfully reduced sedentary time in patients with type 2 diabetes, however that induced no significant improvement of glucose and fat metabolism. Further research is required to determine the degree of reduction in sedentary time and increase in N-LPA needed to improve glucose and fat metabolism.