Engaging in physical activity was proved to have positive effects on physical and mental health in children. Built environment is an important correlate of physical activity participation. School recess provides a daily opportunity for children to be active during school day. Therefore, the purpose of the present article was to review literatures regarding 1) physical activity during school recess, 2) the relationship between recess physical activity and school physical environment, 3) intervention for physical activity promotion during recess by changing school physical environment, and to explore trends of current researches and assignments of future research. A review was conducted and included studies published to May 31, 2011. Twenty-two studies were selected in 1) and showed boys often engaged in more physical activity than girls, but the results on differences in physical activity between ages were inconsistent. Six studies were selected in 2) and indicated recess physical activity was associated with playground environments such as equipments, marking, and surface situate. School environment intervention was observed to be a potential method for promoting physical activity in children by 8 studies in 3). Playground environment with marking, additional play equipments, and designated activity zones increased physical activity during recess. Most researches regarding recess physical activity was conducted in U.S., Australia, and Western countries, and confirmed the effectiveness of recess to promote physical activity. However, few studies on this topic were conducted in Japan. Further researches are needed to draw a conclusion about the possibility of recess to promote physical activity among Japanese children.

We investigated the relationship between daily physical activity level and response inhibition control aspect of cognitive function in older adults using event-related potentials. Twenty-eight Japanese older adults (70.6 ± 3.8 years) participated in the present study. Daily physical activity (PA) was measured using an accelerometer, including step count and the intensity of PA. Participants were divided on the basis of their step count into “Higher PA group” (more than 10,000 steps/day, n = 14) and “Lower PA group”(less than 10,000 steps/day, n = 14). Cognitive function was evaluated by performance, NoGo-N2, and NoGo-P3 while they performed a Go/NoGo task. The results indicated that the Higher PA group exhibited shorter reaction time on Go trials, relative to the Lower PA group. NoGo-P3 amplitude was larger in the Higher PA group compared to the Lower PA group, but NoGo-P3 latency did not differ between groups. PA was positively correlated with NoGo-P3 amplitude. NoGo-N2 component was not related to PA. Thus, PA was more sensitive to monitoring of the outcome of response inhibition rather than pre-motor inhibition in Go/NoGo task. These findings suggest that daily PA is associated with preservation of age-related declines in response inhibition control.

A physical activity reference value for health promotion, 23 METs-h/week was established by the Ministry of Health, Welfare, and Labour in Japan in 2006. The purpose of this study was to determine the daily step counts (steps/day) that classify adults as meeting the 23 METs-h/week reference value by using objective measurements. Objectively measured physical activity levels of 1837 Japanese adults aged from 23 - 69 yrs from both urban and rural Japanese cohorts were provided. Amount of physical activity and daily step counts were assessed using a triaxial accelerometer (Actimarker EW4800; Panasonic Electric Works). Receiver operating characteristics (ROC) curve analysis determined the optimal daily step counts (steps/day) that discriminated adults who met the reference value from those who did not. Approximately 48 % of Japanese adults met the 23 METs-h/week of physical activity reference value. ROC curve analysis found that 9341 steps/day produced 77.1 % of sensitivity and 79.5 % of specificity in all subject. When the analysis was performed in each cohort, 9980 steps/day and 8640 steps/day were indicated as the optimal daily step counts for them to meet 23 METs-h/week in urban and rural cohort, respectively. These data suggest that Japanese adults are likely to meet 23 METs-h/week of physical activity reference value if they accumulate between 8500 and 10,000 steps/day of daily step counts.

The purpose of this study was to determine daily steps corresponding to the reference value for the quantity of Physical Activity and Exercise for Health Promotion 2006 (23 METs·h/wk) considering non-locomotive activities. Two hundred and thirty one men and 224 women wore a tri-axial accelerometer for two weeks. We analyzed the data in each age group (young (less than 40 years), middle-aged (40 to 59 years), and elderly (60 years or more) groups), also. There were significant relationships between daily steps and locomotive activity (r = 0.762 to 0.820, p < 0.001) and total (locomotive and non-locomotive) physical activity (r = 0.706 to 0.824, p < 0.001) with intensity of 3 METs or more in all groups. The daily steps corresponding to 23 METs·h/wk, calculated using regression lines between the daily steps and total physical activities with intensity of 3 METs or more in men and women were 6,534 steps/d and 6,119 steps/d. On the other hand, the daily steps corresponding to 23 METs·h/wk, calculated using regression lines between the daily steps and locomotive activities with intensity of 3 METs or more in men and women were 7,888 steps/d and 8,584 steps/d. These results suggest that non-locomotive activity should also be taken into consideration in the case of assessment of a daily physical activity.

The relationship between body fat growth and physical fitness and motor ability development in school age children is not well understood. We determined the similarities and differences in body fat growth and physical fitness and motor ability development curves by applying cross correlation functions, and attempted to show the structure of growth and development between these attributes. The subjects were 647 boys aged 7 to 15 years. The measurements were height, weight, body mass index and body fat percentage as physical characters; and 20-m sprint, Pro Agility test, side steps, standing long jump, vertical jump, and rebound jump (RJ) index as physical fitness and motor ability. The wavelet interpolation method was applied to growth and distance values for physique, body fat and physical fitness and motor ability, and growth and development curves were derived. Cross correlation functions were then applied to the respective pairs of the compared velocity curves. There were large changes in the behavior of the growth velocity curve around the take off age for height, and so the relationship between body fat percentage and physical fitness and motor ability was investigated using the respective cross correlation functions around the take off age. Before the take off age, positive correlations were seen between body fat percentage and physical fitness and physical fitness and motor ability except for the RJ index. After the take off age, in contrast, there were negative correlations between body fat percentage and physical fitness and motor ability except for the RJ index. These results show the new finding that after the take off age in boys, there are contrary similarity between body fat and speed, agility, and instantaneous force.

The purpose of this study was to examine the effects of 9 weeks of resistance training, with and without static acceleration training (AT), on participants' lower-limb muscle strength, power, and physical function. Healthy participants (19 men and 28 women), aged 65-75 years, were assigned to a static AT group (AT, n = 31) or a non-AT control group (C, n = 16). The AT group and the C group trained three times/week for 9 weeks. The AT group performed unloaded static AT and low-intensity aerobic activity. The C group performed dynamic weight-bearing resistance training without whole-body vibration and the same aerobic activity as the AT group. We collected and analyzed data from 45 participants (AT = 30, C = 15) who completed pre- and post-tests. There was no significant Group × Time interaction on any measurements of lower-limb muscle strength, power, or physical function. Significant time effects were observed in the following tests:isokinetic knee extensor and flexor peak torque, 5-time sit-to-stand, usual gait speed, timed up and go, standing time from a long sitting position, and sit and reach. All of these 7 variables showed positive changes. These results suggest that static AT is a suitable training method having approximately the same efficiency as conventional, weight-bearing, dynamic resistance training for improving lower-limb muscle strength and power, mobility, and flexibility in community-dwelling Japanese older adults.

In this study, the influence of self-weight exercise on changes in the bone mass was evaluated in young Japanese women. The subjects were 69 female university students(age: 21.20±0.30). They were assigned to an exercise intervention (Ex, n=26) or control(C, n=43) group according to their requests. Group Ex performed two sets of 10 sit-up, 10 back-extensions, and 10 squats every day for six months. The height, weight, body fat percentage (TANITA, TBF102), bone mass (quantitative ultrasound, Lunar, A-1000EXPRESS), and urinary deoxypyridinoline (DPD) were measured, and their previous and present exercise habits were examined. Group Ex showed no differences in the bone mass or DPD after the training. Group C, on the other hand, showed a significant decrease in the bone mass (p<0.01) and an increase in DPD (p<0.01) after the training. It was suggested that the bone mass can be possibly maintained through self-weight exercise.

The primary purpose of this study was to investigate whether the baseball pitchers have asymmetric characteristics of muscle thickness (MT) in upper extremities, trunk, and lower extremities because of repetitive pitching. The secondary purpose of this study was to investigate the relationship between MT and ball speed. Twenty-six college baseball pitchers participated in this study. Twenty-six sites were selected to quantify the asymmetric characteristics of MT. The MT was measured by a B-mode ultrasound. The ball speed, measured by a radar gun, was used to quantify the pitching performance. The MT of forearm, subscapula, and chest in dominant side (pitching side) were significantly greater than those in nondominant side, and the MT of abdomen, lateral abdomen, and anterior thigh in nondominant side were significantly greater than those in dominant side. On the other hand, the MT of forearm in both sides and the MT of lateral abdomen in dominant side were significantly and positively correlated with ball speed. These results suggest that asymmetric muscle thickness in upper extremity, trunk, and lower extremity in baseball pitchers resulted from repetitive pitching, and the MT of forearm and lateral abdomen are related to the ball speed.

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.

The purpose of this study was to reveal physiological conditions of commuter cyclist from the standpoint of multiple approaches. Ten male employees (37 ± 9 yr) who usually commute by bicycle participated in this study. Global Positioning System (GPS) was used to analyze their commuting route three-dimensionally. And heart rate was recorded simultaneously to determine their exercise intensity. Blood test, oral glucose tolerance test (OGTT), and maximal aerobic test was conducted in our laboratory. Semantic differential method (SD) questionnaire was conducted to clarify their feelings during and after their commute. The results of blood test and OGTT showed that all of determined values were good and no one exceeded the standard value. GPS log showed that subjects covered 13.3 ± 7.2 km and 40 ± 20 minute with integrating 201 ± 114 meter altitude gain per commute. Heart rate data showed 129 ± 12 bpm per commute. However, subjects demonstrated higher peak heart rate during their commute ranged between 157 and 181 bpm, we determined details by frequency distribution method. The data revealed that commuter cycling was consisted by aerobic exercise with intermittent vigorous intensity exercise. Despite of such a hard exercise cycling to work, the result of SD questionnaire indicated that subjects felt briskness with less tiredness when they commute. Commuter cycling with a higher than moderate exercise intensity, could have good physical and mental effects for employees.