The purpose of this study was to investigate the development of motor control on the aspect of information processing, using a serial stimulus (S)-response (R) system. In this study, major focuses were not only on physical but also cognitive development in children aged 3 to 11.
Subjects executed a task to respond to a set of indicated auditory stimuli as quickly as possible by tapping the board. Each time lag in S-R was recorded.
From the results, developmental characteristics were summarized as follows. 1) In the youngest children group (3-4 yrs), S seemed to promote children's response motion while it also accelerated the motion itself as the stimuli continued. 2) Although younger children (4-5 yrs) could perceive the time lag, they couldn't adjust it to the stimuli while tapping. In the early stage of elementary school children (7-8 yrs) on the other hand, the cognition of time lag in their responses seemed to make them inhibit to go on the tapping. 3) Children (5-6 yrs) became to perceive a set of stimuli as a pattern, furthermore their response motions in themselves were patterned and rarely changed during a sequence. 4) Older children (9-11 yrs) were able to control their motion according to their definite cognitive set almost as well as adults were.

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During heel raising from standing position, the EMG reaction time (EMG-RT) can be devided into two phases, the cognitive factor (LT) and the postural response (DUR), because of the anticipatory EMG activity in the Tibialis anterior (TA) appeared prior to the onset of the EMG activity in the agonist (LG). The aim of this study was to examine the developmental changes of the LT, the DUR, and the ratio of the LT (%LT) and the DUR (%DUR) to the EMG-RT, in the training of normal adults (aged 21 and 23 years) and with advance of the age in normal children (aged between 8 and 15years).
In the training of the adults, The DUR shortened but the LT did not change with shortening of the EMG-RT. With advance of the age in the children, however, the LT shortened but the DUR did not change with the shortening of the EMG-RT. Then, the %LT in the children was larger than that of the adults, while the %DUR was smaller than that of the adults. Thease results suggest that the manner of the develpmental changes of the LT (cognitive factor) and the DUR (postural response) with the shortening of the EMG-RT was different between the traing in the adult and with advance of the age in the children during heel raise from standing position.

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The purpose of this study is to investigate the development of factors that have effects upon gaining ball-speed in kicking motion under two different ball conditions: stationary and tee-up. Fifty one boys aged from 5 to 12 years, were filmed by the use of a high-speed camera operated at 64fps while they were kicking. Multiple regression analysis was applied to get interrelationship among ball speed, maximal swing speed, swing speed, ankle angles and knee angles at the impact. At each stage, from 5 to 12 years of age, the ball speed depended on the maximal swing speed as a whole, especially remarkable under 9 years of age. At the stage of 9 and 10 years of age, ball speed was supposed to depend upon other technical factors as well. At stage of 11 and 12 years of age, in addition to the maximal swing speed, other muscular factors might also be related to the ball speed.

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The purpose of this study is to examine the serial information processing capacity in children and middle-aged and elderly people by using a tracking task of serial pattern.
Subjects tracked two serial patterns twenty times respectively. In experiment I, the task was to switch the key in response to lighting without previous trial. In experiment II, subjects watched the pattern until they felt they had learned it, and then began responding. The stimulus interval (100ms) and the interstimulus interval (500ms) were always constant in experiment I and II. In experiment III, subjects tracked the pattern in 60 trials consisting of 20 trials of three interstimulus intervals (ISI): 500ms, 300ms and 800ms respectively. Samples were 60 right-handed females and males consisting of 10 members of six age groups 8, 10, and 12 years old childern, college students (ages 18-21), the middle (ages 41-43), and the elderly (ages 59-63).
College students could approximately execute the switch task in response to lighting in experiment I and II, and 12 years old children could also execute the same task in experiment II. In experiment I the reaction time of 8 and 10 years old children and middle aged and elderly people were longer than that of 12 years old children and college students by 100-400ms. In experiment II, however, the proportion of the anticipatory response of 8 and 10 years old children were more larger than that of other age groups. When the ISI was prolonged from 300ms to 800ms, the proportion of the anticipatory response of children was more noticeable than that of college students.
Thus 8 and 10 years old children responded to the learned serial pattern by the anticipatory response. However, performance in the middle and the elderly was slow and stereotyped. Twelve years old children, on the other hand, had the similar response properties as in both 8 and 10 years old ones and college students.

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Development of the voluntary movement was studied from the aspect of motor programming changes caused by various stimuli operation. Input stimuli are a group of stimuli that change in the series of time and space. From responses of these series of stimuli, the perception of time, the estimate of reaction, the cancel of motor programming and the change of motion are studied according to the process of its development.
During childhood when a remarkable development in the voluntary motion was made with the growth of nervous system, the estimate of a simple stimulus resembles that of an adult. In case of complicated, advanced stimuli operation, the changes of programming and reprogramming in a child differ from that of an adult. The motion of a 12-years old child gets closer to that of an adult. Temporary change of motion is recognized at the age of 10. In the case of 8-years old children, tehir motions were less streotyped than those of an adult; their programming has greater plasticity. As for the changes caused by stimuli input into either brain (right or left), reaction in children was delayed and was affected with input route of stimuli.

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This study focuses on the development of the sequence of movement of the four limbs in quadrupedal walking and tries to clarify its relation to the position of the neck.
Samples were 60 children aged 3 to 5. A theme was how the locamotion was affected by the position of the neck relative to the body under three conditions: neck straight, neck flextion, neck extention.
It was difficult to interpret the relationship from the results because the sequence of movement of the four limbs in human beings seems to be influenced, at least partially, by visual judjement. The most suitable quadrupedal walking for humans may depend on the individual walker. It can be concluded that the position of the neck relative to the body is not a critical factor in quadrupedal walking.

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In this paper, the established methods of age estimation by tooth attrition were reviewed. The authors have started a joint study on the relationship between dental status and physique/physical function with investigators at the department of preventive dentistry.

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