A whole body indirect calorimeter provides accurate measurement of energy expenditure and the respiration quotient over long periods of time, but has limitations to assess dynamic changes in energy metabolism due to the small amplitude of the signal in relation to the size of the room. The present study aimed to improve algorithm for the whole body indirect calorimetry by adopting a deconvolution with a regularization parameter. Performance of the new algorithm was compared with trends identification (Med. & Biol. Eng. & Comput 34 : 212, 1996) against four validation tests. In a simulated problem, in which metabolic rate cycled with a period of 20 min, mean square errors (MSEs) computed at every 1 min by the deconvolution (0.0036 for O2 consumption and 0.0017 for CO2 production) were smaller than those for trends identification algorithms (0.0198 and 0.0142). Deconvolution algorithm clearly separated individual CO2 infusion of 8 min intervals, while trends identification could no longer separate them. During the validation by ethanol combustion, which produced a near-steady state condition, the deconvolution (MSEs were 0.0022 for O2 consumption and 0.0010 for CO2 production) performed better than trends identification algorithms (MSEs were 0.0086 and 0.0041). When validated against direct measurement of gas production rate during non-steady state condition, produced by a human subject intermittently exercising in the calorimeter, deconvolution (MSEs were 0.0032 for O2 consumption and 0.0038 for CO2 production) performed better than trends identification algorithms (0.0182 and 0.0167). The new algorithm significantly improved transient response of the whole body indirect calorimeter.
The purposes of this study were to investigate the relationships between physical activity variables and physical fitness, and between amount and intensity of physical activity in children and adolescents. Subjects were divided into two groups : 178 children (99 boys aged 9.8±0.6 and 79 girls aged 9.7±0.6) who had not reached the age of peak height velocity (PHV), and 336 adolescents (141 boys aged 15.0±1.1 and 195 girls aged 15.3±1.2) who had reached the age of PHV. Physical activity level (PAL : total energy expenditure/basal metabolic rate) which indicates the amount of physical activity, and time engaged in each of physical activity intensity (light, moderate and vigorous), which indicates the intensity of physical activity were estimated from uni-axial accelerometer. Physical activity was monitored for 3 consecutives days : 2 weekday and 1 weekend day. Moreover, physical fitness test suggested by the Ministry of Education, Culture, Sports, Science and Technology was applied. Results of this study showed that PAL was closely related to physical fitness in children, while time engaged in vigorous activity was more related to physical fitness in adolescents. On the other hand, time engaged in light and moderate activity was closely associated with PAL in younger girls, whereas in younger boys, PAL was closely related to time engaged in moderate and vigorous activity. However, time engaged in moderate activity was more related to PAL in the adolescent group. These results suggest that the relationship between physical activity variables and physical fitness and between amount and intensity of physical activity might vary according to the growth development of boys and girls respectively.
There are various methods for gait exercise in rehabilitation medicine. These methods are useful for patients to control weight bearing and gait pattern. But they have good points and bad points. The purpose of this study was to determine the effects of weight release on cardiopulmonary function during walking, and to examine the potential of this weight-release method in rehabilitation medicine. Subjects were 15 males who had no cardiopulmonary disease or past illness. They wore a respiratory mask connected with metabolic analyzers and a lifting jacket, and they performed three walking tasks on a treadmill at 4.8 km/hour speed for five minutes. During walking, they were lifted up for the weight release employing 3 different traction forces, by a lifting system (Pneu-Weight, Pneumex, Inc.). The three conditions for traction were adjusted for their body weight percentage : 0% (full weight bearing ; FWB), 25% and 50% body-weight release. Each trial was measured with a metabolic analyzing system and electromyography. There were no significant differences among the three conditions in respiratory parameters such as oxygen uptake and minute ventilation. However, systolic blood pressure significantly decreased in the FWB condition. There were various sorts of changes in the integral electromyogram. For example, gastrocnemius increased and decreased, bicepsbrachii increased without weight-releasing, and increased more with weight-release. During exercise, oxygen uptake corresponded to the amount of muscle activity, and ventilation and heart rate were increased by oxygen requirement increases. These results indicate that weight-release saved muscle activity, and gait patterns were changed to less thrust force. The amount of total muscle activity as a postural adjustment and thrust was unchanged in this gait, but muscles used were altered. In rehabilitation medicine, we should give much thought to these changes. This weight-release walking method is useful, because the load can be adjusted according to the breathing circulation constant.
The purpose of present study was to examine validity of accelerometer (Lifecorder ; LC) and to assess the free-living physical activity (PA) in Japanese elementary school students used by LC method. Firstly, to examine validity of LC, twelve children, aged 11.2±1.0 years, were measured total energy expenditure (TEE) by doubly labeled water method and resting energy expenditure (REE) by the expired gas analysis. Physical activity energy expenditure (PAEE) is calculated as 0.9 TEE minus REE. At the same time, PA was evaluated by both daily walk count (WC) and vigorous activity time (LC7-9) using LC method. PAEE per 1 kg body weight significantly correlated with WC (r=0.785, p<0.005) and LC7-9 (r=0.828, p<0.001). Secondly, 140 boys and 167 girls, aged 8-11 years were measured PA by LC method. WC and LC7-9 each were 13000-18000 counts and 16-32 minutes in week-day, and 8000-12500 counts and 8-18 minutes in week-end. PA analyzed by MANOVA were significantly higher in boys than in girls, and lower in week-end than in week-day, and decreased in proportion as grade. Present study suggests that LC method is a good measure of PA in free-living condition for elementary school students.
The decrease of balance capacity is considered as a high risk factor of fall accident, so it is important for the middle-aged and elderly people to keep balance capacity on a high level. In this study, we investigated the effects of aqua exercise on dynamic and static balance function. Thirty-two middle-aged women (56.6±8.1 years) participated a 60-min aqua exercise program three times per week for eight weeks. After exercise intervention, body weight, body mass index, grip strength, side step, shuttle stamina walking test were significantly improved (p<0.05-0.001). Functional reach (p<0.001) and total length of centroid shake with eye close condition (p<0.05) was significantly improved, but with eye open condition was not changed. However, when we evaluate the total length of centroid shake by T-score, static balance performance with eye open and close condition was significantly (p<0.05) improved in the below average groups. In addition, measurement value of functional reach was also improved in these groups. These results indicate that aqua exercise benefits not only physical muscle strength and endurance capacity, but also balance function in middle-aged women. Particularly aqua exercise is more effective for the subjects with lower static balance function before intervention.
This study examined the effects of weight-bearing training on frail elderly whose level of care service is "care level 1" or "support required". Thirty-seven frail elderly (67-94 years old, mean age 82.8±6.8 years, men : N=8, 67-94 years, mean age 81.5±9.8 years, women : N=29, 69-92 years, mean age 83.1±5.8 years) participated in weight-bearing training including the use of a rubber band to improve physical function and lower limb muscle strength for eight weeks. Subjects were measured by a physical fitness test before and after the training. Ninety-two percent of the subjects completed the study. There was a significant improvement in knee extension maximum strength (1 RM)(p<0.01, n=32), functional reach (p<0.01, n=30), and sit-and-reach (p<0.01). There was a significant correlation between initial fitness level and improvement value (sit and reach : r=-0.362, p<0.05, n=33, functional reach : r=-0.563, p<0.01, n=31, stand up and sit down test : r=-0.729, p<0.01, n=31, stepping : r=-0.433, p<0.05, n=33, normal walking speed : r=-0.393, p<0.01, n=34). In conclusion, these results suggest that weight-bearing training may be a feasible and effective means of preventing muscle weakness and physical frailty for frail elderly. However, it is suggested that individual training programs need to be designed considering initial level of physical fitness.