Predictive models of bone mineral density from anthropometric, physical fitness, body composition and quantitative ultrasound variables in overweight and obese Japanese men / 体力科学

The purpose of this study was to develop a simple and easy predictive model of leg, spine and whole body bone mineral density (BMD) from anthropometric, physical fitness, body composition and quantitative ultrasound (QUS) variables. Participants were 138 Japanese overweight and obese men (50.9 ± 9.6 yr, body mass index [BMI] 29.1 ± 2.6 kg/m²). We measured anthropometric variables (height, weight, BMI, chest, waist, hip, upper arm, thigh circumferences), physical fitness (grip strength, side steps, vertical jump, forced vital capacity), body composition (fat-free mass) and QUS. BMD was measured by dual energy X-ray absorptiometry. Multiple linear regression analyses showed that all predictive models for BMD were significant. As a result, the predictive model for leg BMD showed the highest model fitting. The Bland & Altman approaches demonstrated the (positive or negative) systematic error even though most plots were placed within ideal range. Predictive model from physical fitness, body composition and QUS would be useful for estimating whole body and regional BMD. Because these predictive models are likely to have some systemic errors, further research is needed to improve the predictive accuracy.

EFFECTS OF CHANGE IN DAILY PHYSICAL ACTIVITY DURING AN EXERCISE INTERVENTION ON VITAL AGE AND PHYSICAL FITNESS AGE / 体力科学

<b>Purpose</b>：The purpose of this study was to investigate the effects of change in daily physical activity during an exercise intervention on health status and physical fitness.<b>Methods</b>：Participants were 22 obese middle-aged men (BMI : 29.1±2.8 kg/m², 54.1±11.4 yr). They performed 90-min exercise sessions on a regular basis 3 days per week for 3 months. Physical activity (total energy expenditure, TEE ; activity energy expenditure, AEE ; and step counts) was measured using an accelerometer. Daily physical activity was defined as that which was performed outside of the exercise class. A 3-day food record was used to estimate energy intake. <b>Results</b>：Body weight decreased (-3.0±2.5 kg, <i>P</i>＜0.05). Vital age (VA), an index of comprehensive health status, and physical fitness age (PFA), an index of comprehensive physical fitness, significantly improved (VA : -8.7±5.5 yr, PFA : -8.5±5.1 yr, <i>P</i>＜0.05). Energy intake remained unchanged during the intervention (＋63.7±546.1 kcal/d). Daily physical activity increased (TEE : ＋83.0±130.1 kcal/d, AEE : ＋76.9±103.3 kcal/d, step counts : ＋1789±2819 steps/d, <i>P</i>＜0.05). Change in daily physical activity was correlated with change in VA (AEE : r＝-0.52, step counts : r＝-0.46, <i>P</i>＜0.05), while change in daily physical activity did not correlate with change in PFA. <b>Conclusion</b>：These results suggest that changes in daily physical activity during an exercise intervention are associated with improved health status.

PERSONALITY AND SELF-EFFICACY FACTORS IN WEIGHT MAINTENANCE AFTER WEIGHT REDUCTION PROGRAM / 体力科学

The aim of this study was to examine a weight reduction program and residual effects, through confirming the relationship between changes in the morphological and psychological indices including personality and self-efficacy (SE) of the participants. Twenty-five middle-aged women were divided into two groups based on type of weight reduction program intervention. Thirteen women participated in a 3-month diet-only weight reduction program (DO group, 53.3±7.4 yr), and 12 women took part in a 3-month diet and aerobic exercise program (DE group, 48.3±9.6 yr). After the programs, the compatibility score of personality in the DO group was negatively correlated to SE that is indicated as confidence in ability to maintain decreased body weight at 2, 3, and 4 years after the program (r=-0.69, -0.58, and -0.60). It can be seen that personality has an effect on the results of the DO group weight reduction program. Additionally, despite a significant decrease in body-weight and %fat in both groups, only the change of %fat significantly correlated with SE. On the basis of these correlations, the changes of %fat that related to the movability perception of body movements has a greater effect on SE after the program than the information only of weight loss. The results of this study suggest that personality and SE accounted for weight maintenance, and were associated with the results of the weight reduction program.

EFFECTS OF EXERCISE ON VISCERAL FAT IN OBESE MIDDLE-AGED MEN : COMPARISON TO DIETARY MODIFICATION / 体力科学

It has been reported that visceral fat (VF) is an independent predictor of the incidence for coronary heart disease, and is associated with its risk factors. The independent effects of exercise or dietary modification on VF remain to be fully elucidated, especially in obese middle-aged men. The purpose of this study was to investigate effects of exercise on VF compared to dietary modification. Thirty-five obese middle-aged men participated in this study. They consisted of exercise group (n=22, 51.4±11.6 yr, Group E) and diet group (n=13, 48.8±12.2 yr, Group D). Participants in Group E followed 90-min exercise sessions on a regular basis 3 days per week for 12 weeks. Participants in Group D attended weekly classes aimed at maintaining well-balanced 1,680 kcal/d diet for 12 weeks. Body weight decreased significantly in both groups (Group E : −2.9 kg, Group D : −5.4 kg). Visceral fat area (VFA) determined by computed tomography also decreased significantly (Group E : −32.0 cm², Group D : −39.4 cm²). An analysis of covariance adjusted by weight change revealed no significant group difference in VFA change. These results suggest that exercise-induced negative energy balance does not result in greater decrease in VFA as compared with dietary modification alone.

ACCURACY OF ESTIMATING HUMAN BODY COMPOSITION CHANGES ON BI METHODS -WITH THE STUDY OF SERIAL MEASUREMENTS DURING THE WEIGHT / 体力科学

The purpose of this study was to investigate the accuracy of estimating human body composition changes using bioelectrical impedance (BI) methods during a weight-loss intervention. Subjects were forty-three obese men (age : 49.2±10.5 yr, BMI : 27.8±1.7 kg/m²) who completed a 14-week weight-loss intervention. In all subjects, fat mass (FM) and fat-free mass (FFM) were assessed by dual energy x-ray absorptiometry (DXA) as well as single- and multi-frequency BI methods (SBIM, MBIM) before and after the intervention. Resistance parameters were measured by SBIM and MBIM (SBIM : R₅₀ ; MBIM : R∞, R0, and Rfc). In nine subjects these variables were also measured at weeks 1 and 4. Weight decreased (P<0.05) by -8.0±3.2 kg during the intervention while FFM changes averaged -0.4±1.6 kg (DXA), -2.0±1.5 kg (SBIM), and -1.6±1.7 kg (MBIM). BI methods overestimated FFM before the intervention (before ; DXA : 54.4±4.8 kg, SBIM : 56.5±4.3 kg, MBIM : 55.9±4.5 kg). In nine subjects, FFM measured by SBIM (FFM_SBIM) and MBIM (FFM_MBIM) was similar to FFM measured by DXA(FFM_DXA)(after ; DXA : 54.6±5.4 kg, SBIM : 54.6±3.8 kg, MBIM : 54.6±4.1 kg), although BI methods overestimated the FFM before the intervention (before ; DXA : 54.9±5.1 kg, SBIM : 56.9±3.8 kg, MBIM : 56.3±4.4 kg). The ΔFM_SBIM and ΔFM_MBIM were highly correlated with the ΔFM_DXA(SBIM : r=0.87, MBIM : r=0.88). The ΔFFM_SBIM andΔFFM_MBIM were significantly correlated with the ΔFFM_DXA(SBIM : r=0.54, MBIM : r=0.49). The ΔR₅₀ and ΔRfc were also significantly correlated with the ΔFFM_DXA(R₅₀ : r=-0.63, Rfc : r=-0.48). These results suggest that during a weight-loss intervention, 1) BI methods and DXA provide similar estimates of human body composition change, although they overestimate FFM in obese men, and 2) changes of resistance parameters observed with BI methods may estimate human body composition change more accurately.

THE EFFECT OF A SHORT-TERM WEIGHT-LOSS PROGRAM IN OBESE MEN WITH SLEEP DISORDERED BREATHING / 体力科学

A number of studies have shown that sleep disordered breathing (SDB) has a strong relation with obesity. The purpose of this study was to examine the effect of a short-term weight-loss program in obese men with SDB. In our 14-week weight-loss program, forty-one obese men (mean±SD, age ; 49.6±10.8 yr, body mass index ; 27.9±2.5 kg/m²) were assigned to 2 subgroups : diet only (DO ; n=19) and diet plus aerobic exercise (DE ; n=22). 2%, 3%, and 4% oxygen desaturation index (ODI) were measured by pulse oximetry before and after the weight-loss program. Weight and %fat significantly (<i>p</i><0.05) decreased in the total subject pool consisting of DO plus DE (weight ; -8.4±3.5 kg, %fat ; -7.5±3.5%). 2%, 3%, and 4% ODI significantly decreased by -3.46±5.01 event/hour, -2.37±3.57 event/hour, and -1.99±2.84 event/hour, respectively. Significant correlations were found between 2%, 3%, and 4% ODI at baseline and changes of 2%, 3%, and 4% ODI during the weight-loss program (2% ODI ; r=0.48, 3% ODI ; r=0.51, 4% ODI ; r=0.67). Weight loss and %fat loss did not differ significantly between DO and DE (DO : -7.6±3.2 kg, -6.8±3.2%, DE : -9.2±3.7 kg, -8.1±3.7%). The increase in maximal oxygen uptake was slightly larger for DE (4.7±4.6 ml/kg/min) compared to DO (2.5±3.3 ml/kg/min), but there was no significant interaction. Changes of 2%, 3%, and 4% ODI did not differ significantly between groups. These results suggest that for obese men with SDB, the weight-loss program is an effective method, leading to improvement in SDB, although the combination of aerobic exercise to diet may not produce additional effects to SDB, compared with the diet only.