The purposes of this study were to identify typical motor patterns that indicate elementary school children's level of proficiency in squat-vault movement and to consider teaching points according to this level. The analysis subjects were 215 elementary school children (98 boys, 117 girls) from the 5-6th grade. A squat-vault was performed and the motion was recorded from the left and front sides. The motions were scored using evaluation criteria based on the consideration of motion causality. Latent class analysis was used to extract characteristic motions based on the response patterns to the criteria.
The research conclusions were as follows:
1. The squat-vault movements of elementary school children can be summarized as failed vaulting movements, arm-dependent vaulting movements, and strong take-off vaulting movements.
2. Looking at the proficiency of the elementary school students in the squat-vault movements in detail, there were failed vaultings with strong take-off movements and stable vaulting movements.
3. There was a tendency for more failed vaultings with strong take-off movements when the vaulting box was in a portrait orientation and for more arm-dependent vaulting movements in a landscape orientation.
Internationally, it is said that the “era of sleeping difficulty” has arrived, and for Japanese children, this is no exception. On the other hand, it is well-established that daytime light reception promotes phase advances in melatonin secretion. Thus, it is undeniable that the sleep situation and melatonin secretion patterns of schoolchildren may depend on whether the classroom seat where they spend a relatively long time during a school day is on the window side of the classroom. This study examined the relationship between classroom seat location and children's sleep situation and melatonin secretion patterns. Our subjects were 88 elementary school children (47 boys and 41 girls) from the 5th to 6th grades enrolled in public elementary schools in Tokyo; we analyzed the data of 73 (37 boys and 36 girls) with whom there was no data loss. The study was carried out on weekdays from September to October 2018. From the analysis, a 1.7-times difference in the average illuminance median was observed between seats that were on the window side and those on the corridor side (window side group: 362.2 lx, control group: 207.7 lx) In addition, the odds ratio of children with high melatonin (night to morning) was 10-times higher in the window side group than in the control group (OR＝10.179, 95％ CI＝1.492-69.455).
Based on our findings, we conclude that the sleep situation of children should be an important determinant in classroom seating.
The purpose of this study was to clarify the characteristics of body composition of Japanese elementary and junior high school students. In this study, body composition was measured using a body composition analyzer (Inbody470).
In this method, body composition take as a 4-components model (total body water/protein/mineral/body fat mass), and the subdivided data can be easily analyzed. Subjects that were included in this study total 791 students (Boys: 373, Girls: 418) from the 1st grade of elementary school to the 3rd grade of junior high school.
As a result of the analysis, both the boys and girls height and weight gradually increased year by year. The amount of fat-free mass also increased, but body fat mass decreased in boys after the 6th grade of elementary school. For the girls, it increased year by year. The results showed the differences for each gender in all components since junior high school. In particular, there was a marked difference in the 3rd grade of junior high school (total body water: p < 0.001, protein: p < 0.001, mineral: p < 0.001, body fat mass: p < 0.001). In the 4-components, regardless of the age difference in junior high school students, only protein significantly increased in boys (p < 0.05). For the girls, total body water (p < 0.001), protein (p < 0.001), and minerals (p < 0.01) were significantly decreased, and body fat percentage (p < 0.001) was significantly increased.
This study clarified the gender differences and age differences of the 4 components of the body. From these results, the deterioration of the body components especially for junior high school student girls were concerned, and the necessity of taking countermeasures in exercise habits and lifestyle habits were indicated.