We aimed to examine the influence of the leg step on the throwing motion in male children by performing kinematic analysis. The subjects were 36 boys (average age: 4.37 ± 0.26 years). The subjects’ softball-throwing motion was filmed with high-speed video cameras and three-dimensional analysis was performed by using the DLT method. The young children were classified into the following 3 groups according to the step motion of the leg: (1) non-throwing arm side-step group (NTA, n=17), (2) throwing arm side-step group (TA, n=10), and (3) non-step group (NS, n=9). Our results showed that there was no significant difference in ball speed among the NTA (6.6±1.5m/s), TA (6.8±1.5m/s), and NS (5.4±1.3m/s) groups. Subjects in the NTA group showed a great range of rotation and higher rotating angular velocity of the shoulder and waist; however, they did not transfer the energy of the lower limbs to elbow extension angular velocity or ball speed. In contrast, subjects in the TA group showed excessive trunk twisting while throwing; however, they threw the ball with a substantial forward inclination of the trunk. These findings suggested that the step motion of the leg did not influence the ball speed in 3-year old children because the children’s movement patterns were still immature.

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　To determine the variations of myonuclear number and cytoplasm-to-nucleus ratio (domain size) relative to the cross-sectional area (CSA) in the expression of myosin heavy chain (MHC) isoforms, and across fiber types in muscle, the nuclear number and CSA were examined in single fibers from rat soleus (Sol) and medial gastrocnemius (MG) muscles. Confocal microscopy was used to measure CSA, count nuclear number, and to estimate domain size. 　The nuclear number varies across fiber types in rank order, type I > I+IIa > IIa in Sol, and type IId/x > IIa > IIb in MG. In contrast, the nuclear domain sizes varied across fiber types in rank order, type IIa > I+IIa > I in Sol, and type IIb > IId/x > IIa in MG. These results may imply a higher metabolic protein turnover rate per nucleus in type I in Sol, and in type IId/x in MG. 　The nuclei number and domain size seem to vary in relation to CSA in each type of MHC expression and across fiber types in both Sol and MG. We found that higher relationships existed between the number of nuclei and CSA in Sol compared with MG, but, showed that higher relationships existed between the domain size and CSA in MG compared with Sol. These relationships suggest that in fibers from Sol the fiber size is more dependent on nuclear number, however, in the fibers from MG the fiber size is more dependent on domain size per nucleus. Our data suggest that the mechanisms regulating the modulation of the relationship among nuclear number, domain size and fiber size are different in these two muscles.

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　Relations between motivation and adjustment among learners have attracted considerable interest. Self-determination theory has recently received attention as a useful framework to guide understanding the relations. The main purpose of this study was to examine relations between academic motivation and adjustment among learners based on self-determination theory. The secondary purpose was to develop a convenient measure of academic motivation based on the theory. 　In Study 1 on the development of a new academic motivation scale, participants were 157 college students (mean age 19.9 years old). Only 98 of them participated in two sessions separated by four weeks. Results showed adequate reliability and validity of 15-item academic motivation scale with five subscales to measure five regulatory styles in the self-determination theory (non-regulation, external regulation, introjected regulation, identified regulation, and intrinsic regulation). 　In Study 2 on the examination of the relations between academic motivation and adjustment among learners, participants were 200 college students (mean age 21.2 years old). They completed the academic motivation scale and questionnaires about learning-related satisfaction, efforts, self-efficacy, self-actualization, anxiety, interpersonal relationship, and general adjustment. The results showed that more self-determined motivation was positively correlated with academic adjustment, and less self-determined motivation was negatively correlated with academic adjustment. In addition, learners with autonomous motivation style showed better academic adjustment than those with heteronomous motivation style.

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　In this study we applied least square approximation polynomials to the physique and physical fitness of preschool girls in 10-year spans for the 40 years from 1969 to 2009, and investigated the behavior of these mathematical functions. Height, weight, and BMI were measured as parameters for physique, and the 20 m dash, tennis ball throw, standing long jump, one-leg hop, and hanging from a horizontal bar were measured as parameters of motor performance. No further shifts toward earlier or larger growth were seen among parameters of physique. Among parameters of motor performance, declining trends were seen in the tennis ball throw and hanging from a horizontal bar, suggesting decreased upper body muscle strength. A decreasing trend was seen in the 20 m dash and increasing trends were seen in the standing long jump and one-leg hop, although that rising trend has leveled off in recent years. These findings suggest that lower body strength may also shift to a declining trend in the coming years.

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　Recently, a decrease in children’s throwing ability has been recognized. Therefore, it is necessary to examine a simple training method that can be introduced in schools to increase children’s ability to throw. This study analyzes the effect of ball-throwing training (Zero-Mashitanage) on throwing performance in early elementary school children (1-2 year ones and year twos olds) by gender. Subjects included 120 healthy school children: 59 boys (experimental group: 30, control group: 29) and 61 girls (experimental group: 30, control group: 31). They underwent the Zero-Mashitanage training thrice a week for four weeks. The training included throwing a tennis ball 15 times with slightly less than the maximum effort. Results of the two-way ANOVA (one factor repeated measures: experimental and control groups × pre- and post-tests) showed that throwing performance was significantly higher in the post-test than that in the pre-test for both groups of boys and girls. However, change-rates (post-test/pre-test)×100) of throwing performance showed a significant difference in boys, but not in girls. In conclusion, throwing performance improves with Mashitanage training at the frequency of three times a week for about one month in early elementary school children; however, these effects may vary by gender.

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In this study, a least squares approximation polynomial was applied to the mean motor ability development distance of young girls and the changes with age were investigated. A least squares approximation polynomial was also applied to the standard deviation for each age group and a regression evaluation polynomial chart was made. The validity of evaluating motor ability development of young children with this method was then investigated. A motor ability test consisting of 6 items (25-m run, standing long jump, ball throw, two-leg consecutive jump, body support time, and ball catching.) was conducted with 1,714 girls aged 3 to 6 years as subjects. A regression polynomial evaluation chart for these 6 items was made, and the validity of development evaluations for each item was investigated. The following results were obtained. In all motor ability items, especially the 25-m run, standing long jump, and two-leg consecutive jump, the developmental characteristics were clearly seen from the second half of age 3 to the first half of age 5 in these young girls. The results suggest that, in the improvement in motor ability, play that involves motor activity leads to the acquisition of the various motor forms of running, jumping, throwing, and catching from an early stage of childhood. Therefore, since simultaneous comparison evaluations are possible in early childhood even for different ages, it is concluded that age changes in motor ability development can be ascertained more objectively with establishment of an evaluation method that considers the age change composition using least squares approximation polynomial for motor ability development in early childhood.

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