This study aimed to investigate the relationship between risk factors for low bone mineral density (BMD) and vitamin D receptor (VDR) gene Apa I polymorphism in female athletes.

The subjects were 193 female athletes participating in 12 competitive sports (age 20.1±1.0 years). Data on sports participation, age of menarche, prior stress fracture and menstrual abnormalities were obtained by questionnaire survey. The competition types were classified into five types: endurance type, aesthetic type, aquatic type, ball type and high load type in consideration of exercise load characteristics. Whole body BMD was measured by the dual-energy X-ray absorptiometry method (DXA). Analysis of VDR gene Apa I polymorphism was done using the TaqMan® SNP Genotyping Assay.

There was no significant differences in BMD and VDR gene Apa I polymorphism for all competition types. The analysis of low BMD risk factors and BMD in all subjects, indicated that four items (BMI, competition type, age of menarche and prior stress fracture) were shown as significantly related to BMD. As for relationship between low BMD risk factors and BMD in each competition type, prior stress fracture in endurance type, age of menarche in aquatic type, and BMI in ball type and high load type showed a significant negative correlation. As a result of analysis of low BMD risk factor and BMD according to Apa I polymorphism of VDR gene, AA+Aa type significant association was recognized in two items (BMI, competition type). On the other hand, in the aa type, four items (BMI, competition type, age of menarche and prior stress fracture) were shown as significant related items.

It was suggested that risk factors for low BMD has different effects on BMD depending on competition type and female athletes with the expression of Apa I polymorphism aa type of VDR gene may be more susceptible to low BMD risk factor than AA+Aa type.

The purpose of this study was to clarify the actual learning evaluation situation by conducting a questionnaire evaluation of junior high school and senior high school health and physical education student teachers who wished to obtain a license for both men and women. The subjects were 1094 first-year college students (689 males and 405 females) who took dance classes, which are mandatory courses for both men and women. In the questionnaire survey, five questions were asked. Chi-square test was used to evaluate gender differences in answers, while text mining and co-occurrence networks were used for the free description answers. The main results are shown below.

(1) 61.4% of the students selected “creative dance” as their most memorable class.

(2) A total of 81.3% of students replied that their impressions and interests in dance changed positively; and in a co-occurrence network with the consideration of frequently appearing free words, the words “difficult” and “hip hop” were seen to be linked; the “various movements” and “knowing the expression” community were also shown.

(3) 14.9% of the students answered that the dance class was difficult; a higher percentage of whom were male students.

(4) 47.2% of students answered that they were able to tackle the class with an image (consciousness) of when they become teachers.

(5) 61.7% of the students answered that dance classes are different from other practical classes, and in a co-occurrence network with frequent words in free description, the “I often think for myself” community, and the “cooperate and unite in class” community were shown.

This study aimed to examine student teachers’ views of teaching physical education at the Provincial Teacher Training College (PTTC) in Cambodia and to reveal the impact on their views of physical education teaching methods. We conducted a free-description questionnaire survey of 27 freshmen at PTTC concerning their views of teaching physical education. These free descriptions were coded into categories and subcategories using the NVivo12 information analysis software package (QSR International). The results are the following points.

1. The student teachers’ views of teaching physical education included the 2006–2007 objectives and goals of the national curriculum of physical and health education for primary schools in Cambodia and focused on teaching performance and classroom management, based on their educational background in Cambodia.

2. After completing the study of physical education teaching methods, the proportions of the categories changed.

3. Some of the student teachers’ views of teaching physical education changed after studying the physical education teaching methods.

4. Student teachers who had not had the opportunity to take physical education in primary school were likely to rebuild or change their views of teaching physical education.

5. Some student teachers maintained their views of teaching physical education without being influenced by the physical education teaching methods.

A skilled service is important for an effective tennis match. There are primarily three types of tennis service styles: a flat service, a slice service, and a kick service. There is a trade-off between the speed at which a tennis ball is served and its RPM. Studies indicate that a high-quality kick service or slice service requires hitting the ball at a high speed with a rapid spin. Japanese top tennis players including Kei Nishikori have ascended to the top of the rankings at the ATP World Tour tournaments, but no study has quantified the speed and spin rate of tennis balls served by Japanese top-ranked professional male tennis players (Pro group), top university male tennis players (UT group), and top junior male tennis players (JrT group). This study compared and quantified the correlation in ball speed and RPM within the top tier of each competition level in japan (Pro group, UT group, JrT group) to determine the relationship between the level of competition and the service success rate.

The following were revealed. 1) A significant negative correlation between the speed at which a ball is served and its spin rate (trade-off relationship) was observed in all groups, as measured using TRACKMAN. 2) The higher the competition level, the greater the tendency of the values to be at the upper right of the graph (X axis speed, Y axis RPM). 3) The performance of the serve can be evaluated from ball speed, RPM and the number of attempts to achieve the task.

The purpose of this study was to investigate the tendency of injuries and physical characteristics in junior high school soft tennis players and clarify the characteristics of movements associated with the cause of injuries. A total of 20 players(16 males and 4 females) were involved in the study and were divided into the Injury group(n=11) and the Non-injury group(n=9) based on a medical history questionnaire. One person from each group was selected considering their position and handedness, and their forehand stroke motions were recorded using a 3-D motion analysis system. The joint angle was determined from the calculated three-dimensional coordinates. During the swing, participants in the Injury group started the joint movement in the order of trunk, lower extremity, and upper extremity; whereas those in the Non-injury group started the joint movement in the order of lower extremity, trunk, and upper extremity. In the forehand stroke, rotational energy is mandatory to be transmitted from the lower limbs to the trunk and then to the upper limbs for generation of effective swing velocity. It was suggested that deviation from this transmission pattern of the rotational energy could be one of the factors causing the injury.