Relations between daily energy expenditure and body fatness, physical fitness in primary school children using doubly labeled water method and accelerometer / 体力科学

The relationships between physical activity and childhood body size, low physical fitness epidemic are still unclear. The purpose of this study was to examine the relationship between energy expenditure estimated by doubly labeled water (DLW) method and body fatness, physical fitness in children, and the relationship between physical activity levels and percent time spent in activities. 30 healthy Japanese children (20 boys and 10 girls) participated in this study. The total energy expenditure (TEE) and % body fat were measured by the DLW method over a 6-day period. The physical activity-related energy expenditure (PAEE) was calculated as (TEE × 0.90) – basal metabolic rate (BMR). The physical activity level (PAL) was also calculated as TEE/BMR. The physical fitness tests (8 items) were applied to evaluate fitness, and scores of each test were calculated as overall physical fitness score. The TEE was 2009.8 ± 272.6 kcal/day, the PAEE was 558.4 ± 206.1 kcal/day and the PAL was 1.61 ± 0.18. TEE per weight and PAEE per weight (PAEE/wt) was significantly negatively correlated with % body fat (r = - 0.626; r = - 0.400, respectively). These results suggest that increasing energy expenditure is important for achieving adequate body size. The PAEE/wt was most strongly correlated with physical fitness score (r = 0.680). The PAL was associated with percent time spent of inactivity ( r = -0.506), light-moderate activity ( r = 0.450) and vigorous activity ( r = 0.545). It was suggested that physically active lifestyle would be necessary for childhood health.

Relationship between the habitual physical activity and the balancing ability against abrupt acceleration disturbance in elderly females / 体力科学

The purpose of this study was to examine the relationship between balancing ability during abrupt acceleration and the habitual physical activity level of elderly females. Thirty-one elderly females, aged 65-75 years, volunteered for this study. Changes in the center of foot pressure (CFP) were measured during postural sway following platform acceleration, and the response time and CFP displacement were evaluated. The scores of their daily physical activities (TS) -consisting of house-hold activities (HS), leisure time activities (LS) and sports activities (SS) -were estimated by the modified Voorrips's questionaire method. Response time and CFP displacement correlated significantly with age (p<0.001) . Response time also correlated significantly with the SS, LS and TS scores (p<0.05) . CFP displacement also correlated significantly with the SS and TS scores (p<0.05) . These results suggest that postural balancing ability during abrupt acceleration correlates signifi-cantly with the habitual physical activity levels, especially sports activities in elderly females.

Determination of anaerobic threshold in the elderly using integrated electromyographic signals / 体力科学

A study was conducted to examine the feasibility and validity of using integrated electromyographic signals (IEMG) for determination of anaerobic threshold (AT) in the elderly. Twentynine healthy elderly subjects (aged 67.6±7.7 yr) and twelve young males (aged 23.2±7.9 yr) performed ramp cycle exercise to exhaustion, increasing at a rate of 12.5 W/min for the elderly group and 25.0 W/min for the young group, following 3 min of exercise at zero work load. Myoelectrical signals were measured continuously from the vastus lateralis muscle, and values in terms of IEMG were computed every 10s throughout the test with AID conversion at 500 Hz. For the criterion of IEMG threshold, the breakpoint in the relationship between power output and IEMG was determined by two-segmental linear regression. VT was defined as the VO<SUB>2</SUB> at the onset of a nonlinear increase in VE and/or a sustained rise in VE/VO<SUB>2</SUB> without a rise in VE/VCO<SUB>2</SUB>. It was found that the value of VO<SUB>2</SUB> in terms of IEMGT was similar to VT in both groups, 16.3 and 18.1 ml/kg/min for the elderly group and 33.5 and 36.3 ml/kg/min for the young group, respectively. Furthermore, IEMGT was correlated significantly (p<0.001) with VT in both groups (r=0.871 for the elderly group and r=0.925 for the young group) . It is concluded that the IEMGT method for determination of AT in the elderly is simple and useful.

An analysis of physical fitness in the aged people with fitness battery test / 体力科学

Physical fitness of 900 volunteers over 60 years of age were analyzed using a 6-item battery test to obtain fundamental data on the fitness status of the aged Japanese. The test battery consisted of stepping, vertical jump, grip strength, breath holding, body flexion and one-leg balancing, and could be performed safely with relatively mild physical stress in the elderly after simple screening by measurement of resting blood pressure and oral check on mobility problems of the knee and the hip. Males showed significantly higher values in vertical jump, grip strength and breath holding, while females showed significantly higher values in body flexion. There were no sex differences in stepping and one-leg balancing. Lowing trend was found in the score with age in all items except breath holding, but the extent of the reduction differed among the measure elements of fitness. Most of measured items showed significant correlations each other. The values obtained with this test are considered to be useful for future analysis of the fitness of aged people and also to determine the exercise appropriate for them.

ESTIMATION ON ENERGY METABOLISM DURING THE STEPPING EXERCISE / 体力科学

This study was undertaken to examine the mechanical efficiency of stepping exercise on the relations with physical characteristics such as body height, lower limb length, leg length and body weight, and the efficiency was used to estimate the energy metabolism during the stepping exercise. Thirty healthy male students, whose heights ranged from 157.6 cm to 189.0 cm, performed the stepping exercise using a platform from 10 cm to 50 cm. The stepping rate of vertical lifts per minute was fixed to 25 ascents/min., and the height of the platform was increased progressively by 10 cm on every 3 minutes. Oxygen intake during the stepping exercise was measured for the last 1 minute on every stage. Gross, net, work, and delta efficiencies were compited. The results were summarized as follows:<BR>1. It was suggested that there was slightly exponential relationship between energy metabolism and work rate, which was ascribed to the decrease of work and delta efficiencies with increments in work of the stepping exercise.<BR>2. The correlation coefficients between the net efficiency and each physical characteristic were not signifficant for all heights of the platform. This result suggests that the physical characteristics have little or no effect on the mechanical efficiency of the stepping exercise.<BR>3. The mean value and the standard deviation of the net efficiency for heights of the platform above 30 cm were 14.3 and respectively. By using this mean value, energy metabolism during the stepping exercise can be calculated from the equation : Y=0.0163×weight (kg) ×stepping rate (ascents/min.) ×height of the platform (m) +resting energy metabolism (kcal/min.) . The standard error of estimation was ±0.52 kcal. This value was lesser than that calculated from the regression equation between heart rate and oxygen intake during the stepping exercise.