The purpose of this study was to examine whether male high school students can increase their sprinting velocity by improving sprint techniques according to the sprinting abilities in physical education. The participants were grouped according their sprinting velocity by classification criteria (Nishimura et al., 2016) from 139 male students in the 2nd year of high school. The Normal group and the Poor group had 16 and 18 students, respectively. Participants received sprinting instruction over 6 lessons, and 50m sprinting measurements were taken during the 1st and 6th lessons. Their sprinting motions were recorded approximately 35 m from the start line with a high-speed video camera using the side view angle. For evaluating the sprinting motion, joint and segment angles were obtained from the video. The 2 groups were compared using a paired t-test, which revealed significant differences between the pre and post-measurements. Both the Normal group and the Poor group increased their sprinting velocity by improving not so much common sprint technique as specific sprint technique. This result suggested that high school male students could increase their sprinting velocity by improving techniques according to their sprinting abilities.

The purpose of this study was to determine whether physical education lessons focusing on the long jump for elementary school fifth graders would be able to improve their vertical jump velocity. Twenty-eight elementary school fifth graders were instructed in the long jump over 5 lessons. To gain a higher vertical velocity, participants were instructed to pull their swing legs forward at the moment of touchdown and to lean their trunks backward during the jump. Measurements were taken during the first and fifth lessons. To evaluate the jumping motion, the body's center of gravity and segment angles were obtained using a high-speed video camera from a side angle.<br>  The main results were as follows:<br>  1) Since vertical velocity at takeoff and jumping distance were both significantly increased, elementary school fifth graders were able to learn to gain a higher vertical velocity. However, the increase in jumping distance was not due to the increase in vertical velocity but rather a decrease in the distance lost during landing.<br>  2) Although post-measurement showed that the swing legs at touchdown were pulled more forward than at pre-measurement, the change in that motion did not contribute to the increased vertical velocity.<br>  3) At post-measurement, the trunk was inclined more backward than at pre-measurement. Therefore, forward rotation of the body was suppressed at takeoff, which increased the vertical velocity. In addition, suppressing the forward rotation of the body strongly contributed to the decrease in distance lost during landing.<br>

This study aims to reveal necessary sprint techniques based on the abilities observed in male high school students. The participants were 232 boys. The experiment involved the participants performing a 50 m sprint.

Their sprinting motions were recorded approximately 35 m from the start line with a high-speed video camera using the side view angle. The participants were extracted according to their sprinting velocity by following criteria: the Excellent group (35 students, M + 1SD), Normal group (27 students, M ± 0.25SD), and Poor group (27 students, M−1SD). For evaluating the sprinting motion, joint and segment angles were obtained from the video. These were ankle joint angle, knee joint angle, shank segment angle, thigh segment angle, and body trunk segment angle. The three groups were compared through an analysis of variance to explain the significant differences between them. We identified the techniques each group needed to learn for good sprint ability based on these differences.

The results were as follows:

1)<b> </b>The sprint techniques that the Normal and Poor groups both needed to acquire were swinging the free leg forward with a flexed knee just after takeoff and pulling the thigh of the free leg up.

2)<b> </b>Specific sprint techniques that the Normal group needed to acquire were keeping the knee of the support leg less flexed during the support phase and not leaning the body trunk forward excessively at prophase in support phase.

3) Specific sprint techniques that the Poor group needed to acquire were bringing the shank perpendicular to the ground and landing forefoot.

The aim of this study was to ascertain the effects of the number of run-up steps on the distance jumped by fifth graders in the long jump. Such a topic has been studied previously, but participants in those studies were elementary school students with no experience performing the long jump. Elementary school students typically improve their skill at the long jump through physical education classes, so the findings yielded by the aforementioned studies cannot be put to full use in physical education classes. In the current study, fifth graders received 5 hours of instruction in the long jump, and performance was measured 3 times. In the first lesson, long jump attempts were measured with an arbitrary run-up distance. In the fifth lesson, long jump attempts were measured with 9 run-up steps. In the sixth lesson, long jump attempts were measured with 13 run-up steps. The distance jumped each time was compared, but significant differences were not noted. This indicated that the fifth graders participating in this study were unable to improve their skill at the long jump. This means that the current study was unable to achieve its goal. Reasons why participants were unable to improve their skill at the long jump were examined. Results indicated that participants elongated their stride of last step before takeoff to match the takeoff position when attempting a jump with 9 or 13 run-up steps.
identifier:科研費研究者番号 : 00792201
identifier:J-GLOBAL ID : 201901005962474052
identifier:科研費研究者番号 : 00806177
identifier:J-GLOBAL ID : 200901089968097589

identifier:J-GLOBAL ID : 200901089968097589