The purpose of this study was to examine time trend changes in the amount and type of physical activities obtained by an accelerometer and an activity record over a 20-year period in urban elementary schoolchildren. A total of 388 sixth-grade children (11–12 years old) in an elementary school in Kyoto participated in the study (n = 125 in 1999, 108 in 2009, and 155 in 2017/2018). The size and shape of the school district did not change. The school schedule was nearly the same in 1999, 2009, and 2017/2018. The children were instructed to wear an accelerometer for 5 consecutive weekdays and to keep minute-by-minute activity records with the assistance of their parents. The percentage of overweight/obese children increased with time, but the increases were not significant. The step count per day, activity energy expenditure, and physical activity level were significantly lower than they were 20 years ago, and they were significantly higher than they were 10 years ago. The time spent playing outdoors was significantly shorter than it was 20 years ago, and while it was significantly longer than it was 10 years ago. Independently from year, the time spent playing outdoors was strongly correlated with accelerometer-derived physical activity. The time spent walking to school, sleeping, studying in girls was correlated with accelerometer-derived physical activity. The factor of activity pattern related to secular changes of accelerometer-derived physical activity over the 20-year period is the time spent walking to school, sleeping in boys and the time spent club activity in girls.

This study aimed to examine characteristics of physical functions, physical activity, and cognitive functions among community-dwelling older people who stopped driving automobiles. Participants were 589 community-dwelling older people (age: 65–89, 71.4 ± 5.1 years; 403 men, 186 women). The participants underwent nine physical assessments—hand grip strength, knee extension strength, timed up-and-go test, chair stand, one leg standing with open eyes, functional reach, vertical jump, preferred gait speed, maximal gait speed—and were evaluated for physical activity; and five cognitive assessments—the Mini-Mental State Examination (MMSE), Logical Memory I and II (WMS-R LM-I, LM-II) subtests of the Wechsler Memory Scale-Revised; and Trail Making Test A and B (TMT-A, TMT-B). They were divided into current driver (379 men, 169 women) and driving cessation (24 men, 17 women) groups. Among men, the driving cessation group had poorer vertical jump, TMT-A, and TMT-B results, while women had poorer hand grip strength, one leg standing with open eyes, WMS-R LM-II, and LM-II results, and longer inactivity time, compared with the current driver group and adjusted for covariates (P < 0.05 for all). The findings suggest driving cessation among community-dwelling older people is significantly associated with poorer physical functions, physical activity, and cognitive functions compared with those in current drivers.

This study examined whether physical and cognitive function was independently associated with risk of Musculoskeletal Ambulation Disorder Symptom Complex (MADS) in community-dwelling older people. We examined 640 older people (315 men, 325 women; 65–89 years). We assessed physical performance by one-leg standing with eyes open, timed up and go (TUG), muscle strength, muscle power, and gait speed. Cognition was assessed using Mini-Mental State Examination (MMSE), Clinical Dementia Rating (CDR), and Trail-Making Tests (TMT) A and B. We divided participants by physical function into “MADS” (one-leg standing < 15s or TUG ≥ 11s) and “non-MADS”, and identified cognitive impairment if MMSE was < 27 and CDR ≥ 0.5. We also grouped by sex and age (younger-old: 65–74 years and older-old: 75–89 years), and controlled for age, Body Mass Index, education and steps. Physical and cognitive function was significantly worse in the MADS groups. The younger-old men had poorer muscle strength, muscle power and TMT-A. The younger-old women had poorer muscle power, gait speed, MMSE and TMT-B. Older-old men had poorer muscle strength, and older-old women poorer gait speed (P < 0.05). The MADS groups also had significantly higher adjusted odds ratio (OR) for cognitive impairment (younger-old men: OR: 4.62; 95% confidence interval [CI]: 1.08–19.8; younger-old women: OR: 6.09; 95% CI: 1.03–35.9; P < 0.05). This study suggested that poorer physical and cognitive function was significantly associated with the risk of MADS, and these associations may be differ with sex and age.

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.

The purpose of this study was to examine the relationships between patterns of daily physical activities measured by accelerometer and physical activity level (PAL) in children. Firstly, activity intensities during incremental exercise were measured using a tri-axial accelerometer (HJA-350IT) in twenty one children aged 10.6 ± 0.9 years. As a result of receiver-operating characteristic curve analysis, the cut-off value for discrimination between walking and running activity was set at 7.2 METs of HJA-350IT. Secondly, total energy expenditure (TEE) in daily life was measured by doubly labeled water method, and durations of lifestyle, walking, and running activities were measured by the accelerometer in 6^th grade elementary school children (11 boys and 10 girls). TEE and physical activity level (PAL) were 2,021 ± 343 kcal/day and 1.56 ± 0.17, respectively. The average durations of lifestyle, walking and running activities were 188 ± 30 min/day (50.6 ± 6.0 %), 171±28 min/day (45.9 ± 5.0 %) and 13.3 ± 7.6 min/day (3.5 ± 1.8 %), respectively. The proportion of the duration of running activity was positively correlated with PAL (r = 0.615, p < 0.01), and the proportion of the duration of lifestyle activity was negatively correlated with PAL (r = -0.439, p < 0.05). There was no relationship between the proportion of the duration of walking activity and PAL (r = 0.300, n.s.). These results suggest that running activity is important to increase PAL more than ever in primary school children.

Although skeletal muscle mass decreases with aging, its decrease rate may differ among parts of the body. There have been few studies examining the differences in the muscle mass decrease rate between proximal and distal parts of the limbs or between the left and right legs in a large population. Bioelectrical impedance (BI) index, calculated as the ratio of the square of segment length to impedance, is linearly correlated with the muscle mass calculated by MRI (r=0.902-0.976, p<0.05, Miyatani et al., 2001) in the limb segments. The purpose of this study was to examine differences in the decrease rate of muscle mass between the proximal and distal parts of the limbs and between the upper and lower limbs in healthy Japanese. The BI index was measured in the bilateral thighs, lower legs, upper arms, and forearms of 1006 healthy Japanese men and women (aged 15-97 years). While the BI index decreased with aging in all examined parts of the body, the decrease rate was larger in the lower limb than in the upper limb, and in the thigh than in the lower leg. The percentage of people who showed a difference of more than 10 % in the BI index between the left and right lower limbs was significantly higher in the elderly than in young subjects. These differences in the decrease rate of muscle mass between limbs may be associated with decreases in physical functions in the elderly.

In this study, the states of obesity, physical activity, and diet of 4 th-6 th graders were examined in an agricultural area of the Tohoku region, where many pupils are driven to and from school. The physique (height, weight), physical activity level (Select 2 ; Kenz), and nutritional intake were investigated in 32 elementary school pupils for one week.The subjects showed the following characteristics : 1) A high percentage of obese pupils, 2) a small number of walking steps, and 3) a lower percentage of obese pupils than non-obese pupils participating in sports activities. Therefore, efforts to increase the physical activity level are considered to be necessary for the prevention of obesity. For this purpose, in addition to administrative measures to increase exercise opportunities in the community such as the establishment of a general sports club, local movements such as encouraging pupils to walk to school may be effective.

An Elderly Health and Fitness Promotion Program was carried out in the 32 on areas of Ichihazama Town (now Kurihara City), Miyagi Prefecture to promote the health of the elderly population by making as many townspeople as possible aware of their health and fitness levels, and develop active lifestyles. We evaluated the effectiveness of this program on the basis of the results during the past 4 years.In 2001, the Elderly Health and Fitness Promotion Program was started in each of the town's 32 administration areas. The number of participants continued to increase until it exceeded 600 in 2004, with increases in the percentages of males, those aged 80 years or above, and those withlimited ADL among the participants. While the results of fitness tests varied widely and were very low in some participants, changes in the fitness level were small in regular participants.

In the context of energetics related to a pendular model, the mechanical power (W) and ‘pendular motion efficiency’ (PME) were determined during walking of the subjects who consist of 37 healthy elderly women (65-85 years) and 21 young women (18-25 years) . Using a force plate, the potential and kinetic energies of the body's centre of mass were measured at various constant speeds. Walking speeds were selected and controlled by a newly devised pace-maker. PME, which is equivalent to ‘% recovery’ by Cavagna (1976), indicates a sort of efficiency in transforming potential energy into kinetic energy and vice versa. The external power to accelerate the body (Wext ), which is thought to be supplied by muscles, increased with walking speed, and the rate of increase in Wext tended to be greater in the elderly than in the young subjects. It was noted that the maximal PME values at the optimum speed in both age groups were comparable, but PME values in the elderly decreased more markedly than in the young subjects as walking speed deviated from the optimum. This fact suggests that an adaptability to different walking speeds reduced in the elderly population.