This study aimed to verify the effect of playing in specific exercise programs on improvement of motor ability. Various play elements with emphasis on intrinsic motivation in preschool children were introduced, and free-flow play was compared with ladder challenge play, circuit challenge play. The subjects were 76 preschool children (40 boys and 36 girls) aged 4 and 5 years old. Among the above subject, 15 consisted of a group that played ladder challenge, 31 served as the group that played with circuit challenge and 30 formed the group with free-flow.
The playing activities by the ladder challenge group included seven kinds of tasks. Playing activities by the circuit challenge group performed six kinds of tasks. They performed fundamental ability tests (25 meter dash, standing long jump, tennis-ball throw, continuous bilateral hop, self body support using both hands, ball catch, jump over and crawl under, grip strength, forward bend).
Results were as follows.
1) In the case of 25-meter dash, the experimental the ladder challenge group & circuit challenge group set better records than free-flow play group.
2) In the case of standing broad jump, the ladder challenge play & circuit challenge group set better records than the free-flow play group. Boys set better records than girls.
3) In the case of jump over and crawl under, boys from circuit challenge play and ladder challenge play finish faster than those from free-flow play. On the other hand, girls from free-flow play and ladder challenge play finish faster than those from circuit challenge play.
4) In the same event, we can identify some significant distinction according to gender only within the experimental group of circuit challenge play. Girls finish faster than boys.
5) Some element of intrinsically motivated free-flow play enables children to experience multiple activities and, repetitive physical activities, without being bored.
It is proved here that the physical exercise programs, which incorporate intrinsically motivated free-flow play, enhance motor ability more than free-flow play, especially in activities that contain locomotive movement pattern and manipulative movement pattern.

At present, it is recommended that children perform at least 60 min of physical activity per day. However, the duration of physical activity inevitably depends on subjective assessment. Therefore, this study aimed to clarify the discrepancy between subjective and objective assessments of the duration of physical activity, and the 2nd aim of this study propose guidelines in terms of the number of paces needed to ensure people perform at least 60 min of physical activity. The results clarified the following points:
Subjective assessments of physical activity tend to overestimate the duration, and this tendency is particularly strong in the group belonging to sports clubs. While the non-sports club group showed a reduced tendency to overestimate the duration.
The guideline numbers of paces are approximately 12,500～13,000 paces as an index for ensuring 60 min of LC3-9 (walking intensity or greater), approximately 15,500～16,000paces as an index for LC4-9. These may be regarded as the basic number of paces, the recommended number of paces.

In this study, the association of parental exercise preferences with children's fitness were investigated in 546 children of 1-6 grades and their parents in a local public- and a suburban private school. As a result, even though adjustments were made with other factors related to physical fitness, the odds ratio for children's low fitness was 6.4 in the group of parents having low exercise preferences, which was significantly higher than that of parents having high exercise preferences. The odds ratio of children's low fitness in the group of either parent having high exercise preference was almost equal to that in the group of both parents having high exercise preferences. On the other hand, no significant association was recognized between children's fitness and the actual exercise habits of each parent. In conclusion, it was considered that the parental exercise preferences might be one of the strong relevant factors of children's fitness.

The purpose of this study was to investigate the association between continuous exercise and engagement in sports activities from junior high school and generalized self-efficacy (GSE) during senior high school in male students.
Methods:
We conducted this study at a private boys' senior high school in Japan. A self-report questionnaire assessing previous (i.e., junior high school) and current (i.e., senior high school) exercise and sports practices was administered to all 1st and 2nd year students in physical education classes; cross-sectional data were obtained from 1,187 students (response rate: 83.0％). We evaluated current GSE using the Japanese version of the GSE Scale. Subjects were divided into the following six groups based on whether they belonged to a sports club at junior high school (belonged or did not belong to sports club) and exercise and sports habits in senior high school (no practice, individual practice, belonged to a sports club): 1) never belonged to a sports club (did not belong/no practice, n＝96), 2) stopped belonging to a sports club (belonged/no practice, n＝454), 3) began sports individually (did not belong/individual practice, n＝10), 4) continued sports individually (belonged/individual practice, n＝79), 5) began belonging to a sports club (did not belong/belonged, n＝21), and 6) continued belonging to a sports club (belonged/belonged, n＝527). We used analysis of covariance (ANCOVA), adjusting for potential cofounders, to compare GSE between the six groups.
Results:
As a result of the ANCOVA, the following three groups had significantly higher GSE than the never belonged to sports club group: the stopped belonging to a sports club, continued sports individually and continued belonging to a sports club groups. Additionally, the continued sports individually and continued belonging to a sports club groups had significantly higher GSE than the stopped belonging to a sports club group.
Conclusion:
These results suggest that belonging to a sports club from junior high school to senior high school may enhance GSE in male adolescents. However, stopping involvement with a sports club and individually continuing exercise or sports may also be effective for enhancing GSE.

A survey was conducted to assess physical activity, depression, and sense of coherence among early adolescents. This study used a cross-sectional sample of 12,086 students (G5-G9) from 28 public elementary schools and 22 public junior-high-schools in Japan. A total of 9,424 students (G5-G8) were surveyed from December 2013 to December 2015 using the International Physical Activity Questionnaire (IPAQ) -short form to measure physical activity (PA), the Depression Self-Rating Scale for Children (DSRSC) for depressive symptoms, and the Sense of Coherence Scale-13-item version (SOC-13).
Vigorous PA (VPA) of the G5 boys (4h 20 min) was significantly longer than that of the G5 girls (1h 30min) and the VPA of the junior-high-school students increased significantly compared with that of the elementary-school students. The VPA of the G8 boys reached 6h 30 min, whereas that of the G8 girls approached 3h, which was a significant difference. Additionally, more junior-high-school students participated in sports-club activities than did elementary-school students.
The mean DSRS-C score of the G5 girls (10.24±5.73) was significantly higher than that of the G5 boys (9.31±5.31). No other differences by grade, were found among the elementary-school students. The depressive symptoms of the junior-high-school students indicated they had a greater risk for depression than the elementary-school students did.
The mean SOC score of the G8 boys (44.58±8.11) was higher (better) than that of the G8 girls (43.46±8.30). Furthermore, the elementary-school students' score on the SOC was higher than that of the juniorhigh-school students; the score tended to decrease as the grade increased.