Taiikugaku kenkyu (Japan Journal of Physical Education, Health and Sport Sciences)
Online ISSN : 1881-7718
Print ISSN : 0484-6710
ISSN-L : 0484-6710
Volume 51, Issue 4
Displaying 1-11 of 11 articles from this issue
Reviews
  • Masanobu Wada, Makoto Sakamoto, Minako Sugiyama, Satoshi Matsunaga
    2006 Volume 51 Issue 4 Pages 399-408
    Published: 2006
    Released on J-STAGE: January 25, 2008
    JOURNAL FREE ACCESS
    Skeletal muscles induced to contract repeatedly respond with a progressive loss in their ability to generate a target force or power. This decline in function, referred to as muscle fatigue, has a complex etiology that can involve various metabolic and ionic factors. Of these, intracellular acidosis due to lactic acid accumulation has been regarded as one of the important causes of muscle fatigue that occurs with intense exercise. Recent surveys, however, have demonstrated little direct effect of acidosis on muscle function at physiological temperatures, and in fact several putative mechanisms by which intracellular changes can attenuate contractile function have been proposed. The most likely mechanisms to explain muscle fatigue include elevated inorganic phosphate concentrations that result from phosphocreatine breakdown, compartmentalized depletion of endogenous muscle glycogen and/or modification by reactive oxygen species that are produced extensively in contracting muscle fibers. This brief review seeks to examine how these three alterations contribute to muscular fatigue processes.
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  • Masaaki Kagawa
    2006 Volume 51 Issue 4 Pages 409-419
    Published: 2006
    Released on J-STAGE: January 25, 2008
    JOURNAL FREE ACCESS
    The present paper reviews the effects and problems associated with the use of personal computers in physical education, and seeks more effective methods of use for this purpose. First, previous reports about computer use in physical education were divided into the two categories: Measurement and Assessment, and Computer-assisted Instruction or Computer-assisted Learning. Second, reports belonging to the two categories were reviewed, and checked from the viewpoint of using effects verification. Finally, the potential and the noteworthy points were discussed in relation to future use of computers in physical education. The results obtained through these steps are summarized as follows; 1. Many kinds of application software have been developed and used in physical education, but there are few reports in which strict verification of the effects has been discussed. Although limited in extent, effects at a cognitive level have been suggested in physical education classes for primary and junior high school children, and effects on knowledge acquisition and motor skill acquisition have been suggested in physical education classes for high school and college students. 2. For future effective use of computers in physical education, stricter verification of the effects through practical study involving qualitative analysis or case studies, introduction of new techniques, and adequate consideration of relevant problems are necessary.
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  • Mitsuo Matsuda
    2006 Volume 51 Issue 4 Pages 421-433
    Published: 2006
    Released on J-STAGE: January 25, 2008
    JOURNAL FREE ACCESS
    The age-related decrease in arterial distensibility, particularly central arterial distensibility, may increase systolic blood pressure and/or pulse pressure in the elderly. Previous studies have shown that daily physical activity is positively related with arterial distensibility, and that aerobic exercise training could improve arterial distensibility. Some likely biological mechanisms through which aerobic exercise improves arterial distensibility have been revealed. Thus, habitual physical activity and aerobic exercise training may retard age-related changes in the arteries, and prevent cardiovascular and cerebrovascular diseases in the elderly. However, more studies targeting diverse groups are needed to clarify the optimal use of aerobic exercise training in the management of arterial distensibility.
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  • Komei Hattori
    2006 Volume 51 Issue 4 Pages 435-446
    Published: 2006
    Released on J-STAGE: January 25, 2008
    JOURNAL FREE ACCESS
    Obesity is a condition resulting from excess body fat, and is associated with several risk factors for chronic diseases in later life. Hence, the prevention of obesity is a public health priority, with much of the concern focusing on childhood and adolescence. Recently, body mass index, calculated as weight divided by height squared (BMI, kg/m2), has been widely used as a surrogate measure of adiposity for children and adolescents, and international age- and sex-specific cut-off points to define overweight and obesity have been proposed. Various surveys using the international BMI criteria have revealed that the prevalence of child obesity is accelerating throughout the developed world. However, BMI is a measure of excess weight relative to height, rather than excess body fat. The interpretation of BMI among children and adolescents is further complicated by the changes that occur in weight, height, and body composition during growth. There is a now a considerable body of evidence that during the growth stages, weight increase is frequently due to an increase in fat-free mass rather than fat mass. Therefore, application of the BMI norm to define overweight and obesity in children and adolescents should be done with caution. Furthermore, it is necessary to be aware that adopting an international standard for a specific population may introduce error because the relationship between BMI and adiposity is race-specific. For this reason, it is expected that race-specific standards of BMI with additional body composition-related information for children and adolescents will become available in the future to ensure reliable assessment of adiposity levels.
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Original investigations
  • Takashi Mitsui, Koji Zushi
    2006 Volume 51 Issue 4 Pages 447-457
    Published: 2006
    Released on J-STAGE: January 25, 2008
    JOURNAL FREE ACCESS
    In the present study we investigated factors increasing stride length in the elderly during walking in order to devise an effective training method for improvement of walking ability. Nine elderly subjects (84.1±6.1, 73-93 yr) walked at three different stride lengths (free, wide, and supra-wide) on a floor. Kinematics and ground reaction forces were recorded by using a video camera and force plates. Walking was modeled as an inverted pendulum system including a compliant leg, connecting the center of gravity and the center of pressure (pendulum leg). The decline of speed with age during free walking was affected by stride length (r=0.810, p<0.01), but not stride frequency (r=0.122, n.s.). With increasing stride length, the range of the pendulum angle was significantly greater in both the former (r=0.998, p<0.001) and latter (r=0.995, p<0.001) phases. Also, the amount of change in the pendulum leg increased significantly in both the former (r=0.752, p<0.001) and latter (r=0.943, p<0.001) phases with the greater kinetic demands related to pendulum angle. These results were clearly demonstrated when we compared faster subjects with slower ones under any stride conditions. It is concluded that with a large change in the pendulum leg, the spring-like behavior of a leg could be an important factor enabling elderly people to produce greater pendulum rotation, which is necessary to increase stride length.
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  • Motoki Okumura, Shigeru Yoshida
    2006 Volume 51 Issue 4 Pages 459-470
    Published: 2006
    Released on J-STAGE: January 25, 2008
    JOURNAL FREE ACCESS
    A study was conducted to examine the processing efficiency of response selection in collegiate kendo players. Skilled and sub-skilled groups (each n=8) reported their skill knowledge utilized in practices and matches. Experimental tasks in which subjects found and attacked the vulnerable points of an opponent were solvable with skill knowledge, and had three levels of difficulty. For the tasks, the two groups participated in a motor skill confirmation experiment, and a response selection experiment with environmental interference (with and without attacks by an opponent). Five attacking trials were allowed for one subject in each task. It was verified that both groups had acquired skill knowledge and motor skills of the same grade. Although the thinking processes in response selection were almost the same in both groups, the skilled group used their skill knowledge more frequently and had higher scores in terms of time efficiency and skill exertion. The results showed that the skilled group selected responses actively and frequently by anticipating with their skill knowledge, and this processing function was robust against environmental interference. Such active response selection, which differs from the passive processing of environmental information by skilled players in other studies, indicates that the processing mode in response selection changes according to the characteristics of a sport. Kendo players should acquire effective skill knowledge, then utilize it actively and frequently in response selection in order to refine that knowledge and reinforce the processing function.
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  • Yoichi Hayashi, Shigeharu Numao, Masaki Nakagaichi, Kiyoji Tanaka
    2006 Volume 51 Issue 4 Pages 471-481
    Published: 2006
    Released on J-STAGE: January 25, 2008
    JOURNAL FREE ACCESS
    The safety of cardiorespiratory function is an accentuated factor in exercise prescription for improvement of physical fitness. When regulating exercise intensity using a self-selected exercise intensity (SSEI) method, it is important to not only consider responses in cardiorespiratory function but also the safety of exercise intensity. In this study, therefore, we compared changes in cardiorespiratory function during exercise at anaerobic threshold (AT) and by the SSEI method. In addition, we attempted to acquire new information regarding the safety of the SSEI method. Group 1 consisted of 28 healthy men, aged 25.5 ± 2.7 years, who completed two 20-min exercise trials. During the first trial, participants performed cycling for 20 min by the SSEI method (SS-trial). The second trial consisted of 5 min of fixed-load cycling at 70% (high intensity) of Vo2max (SSFL70%) followed by 15 min of cycling at SSEI. Group 2 consisted of 10 healthy men (25.0 ± 1.8 years) who completed two 20-min exercise trials at AT (AT-trial) and Above AT (AbAT-trial). Oxygen uptake during the SS-trial increased to the same level as that during the AT-trial. However, it was noteworthy that the exercise intensity selected by each subject was maintained at approximately 65%Vo2max during SSFL70%. These data suggest that a constant-load exercise relative to AbAT level can be sustained for a prolonged period of time without inducing a marked risk for the cardiorespiratory system.
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  • Hiroo Takahashi, Akira Maeda, Hidetsugu Nishizono, Hiroshi Kurata
    2006 Volume 51 Issue 4 Pages 483-492
    Published: 2006
    Released on J-STAGE: January 25, 2008
    JOURNAL FREE ACCESS
    The purpose of the present study was to elucidate tactical strategies for winning a tennis match. Forty-two men's singles matches in the 1997 and 1998 Kyushu collegiate tennis championships were analyzed. Analytical criteria were the relationship between point-winning at each score and the techniques used. In the present research, techniques were categorized into the following 5 groups: service, return, stroke, offense and defense. The following results were obtained: 1. Stroke was the most frequently utilized technique regardless of point-winning. 2. Return and defense techniques, which are considered “passive” techniques, produced significantly high rates of point-losing. 3. The rate of point-winning by service was low at high rate counts (HRC), but high at low rate counts (LRC). In contrast, the rate of point-losing by service was high at LRC-game-points. The rate of point-winning by service was higher for players leading in score, and was low at important scores. 4. The rate of point-winning by players using the defense technique was high at HRC-opponent's game-points. To win a point using passive techniques is the most important tactic at opponent's game-points. 5. The rate of point-losing during the offense technique was high at LRC-up counts. Offense techniques are effective for winning points; however, they involve a higher risk of losing points. These results indicate that players should analyze the relationship between point-winning and strategies at each score.
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  • Banjou Sasaki
    2006 Volume 51 Issue 4 Pages 493-503
    Published: 2006
    Released on J-STAGE: January 25, 2008
    JOURNAL FREE ACCESS
    This study examined the relationship between precompetitive state anxiety and competitive trait anxiety, sport motivation, sport achievement orientation, stress appraisal, and stress coping prior to competition. Sixty-five male junior high school baseball players responded to the Competitive State Anxiety Inventory-2 (CSAI-2) on three occasions during the precompetition period: 1 week, 2 days, and 1 day before competition. They also completed a series of questionnaires 1 week prior to competition, measuring sport competitive trait anxiety (SCAT-C), sport achievement goals (TEOSQ), sport motivation (SMS), and their stress appraisal and stress-coping style when they were unable to exhibit anticipated performances in their club activity. Path analyses were employed in order to clarify the dependence of these psychological factors on the basis of the Lazarus stress model (Lazarus and Folkman, 1984). It was found that the junior high school baseball players were distressed, reported high precompetitive trait anxiety and high amotivation, or reported themselves to have a high intrinsic motivation to accomplish their goal, when they felt they were unable to fulfill assignments during club activity. However, players who considered that they could cope positively with stressful circumstances reported low precompetitive state anxiety.
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  • Miwako Bandou, Satoru Tanabe, Akira Ito
    2006 Volume 51 Issue 4 Pages 505-514
    Published: 2006
    Released on J-STAGE: January 25, 2008
    JOURNAL FREE ACCESS
    A study was conducted to clarify the relationship between hammer throw performance and hammer head velocity during four-turn throwing. Hammer head movements of 26 male hammer throwers including from world's top-ranking athlete down to unskilled level performing the four-turn throwing method were filmed at 60 fps using two video cameras at five athletic competitions. The hammer head was digitized and the three-dimensional coordinates were calculated using the DLT method. The results revealed a significant positive correlation between throw distance and the initial velocity of the hammer head (r=0.917, P<0.001). However there were no significant correlations between throw distance and the release angle of the hammer head, or between throw distance and the release height of the hammer head. The velocity of the hammer head increased with the number of turns, and the maximum velocity of the hammer head at each turn showed a significant positive correlation with the throw distance. The radius of curvature of the hammer path was calculated from the velocity and acceleration of the hammer head. The hammer head showed greater tangential acceleration when the radius of curvature of the hammer path was reduced. Furthermore, the normal acceleration increased during the phase when the radius of curvature of the hammer path was reduced.
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  • Tsuyoshi Takeda, Hiroshi Ichikawa, Seiji Sugimoto, Takeo Nomura
    2006 Volume 51 Issue 4 Pages 515-524
    Published: 2006
    Released on J-STAGE: January 25, 2008
    JOURNAL FREE ACCESS
    The starting technique is one of the most important factors for sprint performance in competitive swimming. Take-off velocity and take-off angle determine the horizontal take-off velocity and flight distance in the aerial phase. The most appropriate take-off angle for start performance has not been investigated, although the importance of take-off velocity is well known. The purpose of this study was to clarify the effects of take-off angle on take-off velocity, flight distance and block time during swim-start. Twelve elite competitive swimmers performed three different types of start trial. In the experimental starting trials, swimmers were instructed to take off from the starting block higher (High) and lower (Low) than the usual grab start trial (Normal). The starting motions of subjects were recorded by a high-speed camera (Photron FAST-CAM PCI, 250 fps) and the 2D-DLT method was used for calculating the kinematic variables. The starting movement was modeled by a pendulum model, and the take-off velocity was resolved to the rotational component and the extensional component. A decrement of the take-off angle resulted in an increment of rotational component, extensional component of take-off velocity. Therefore, the decrement of flight distance with decrement of the take-off angle resulted in fewer disadvantages for start performance. In addition, there was no correlation between take-off angle and the block time in Normal trials. Considering the importance of horizontal take-off velocity, which is in the direction of swimming, take-off angle should be approximately 0 degree in the aerial phase.
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