Journal of the Society of Biomechanisms
Print ISSN : 0285-0885
Volume 34, Issue 4
Displaying 1-15 of 15 articles from this issue
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Papers
  • Shogo MIYAZAKI, Tatsuro KATO, Hiroshi YAMADA, Keita OGAWARA, Takashi U ...
    2010 Volume 34 Issue 4 Pages 312-316
    Published: 2010
    Released on J-STAGE: April 15, 2016
    JOURNAL FREE ACCESS
    The purpose of this study was to investigate the development of the activity of running in infants. Kindergarteners (n=102, 71.2±6.6age of the moon) and primary schoolchildren (n=18, 87.8±3.7age of the moon) were examined over a period of one year for the following three parameters in a 25-m race: running speed, step frequency, step length . Partial correlation analysis showed a very high significant correlation between the rate of change of step frequency and that of running speed. Therefore, it was suggested that increase in running speed (m/sec) was due to not only increase in step length (m/step) but also increase in step frequency (step/sec). Furthermore, the low and middle age groups showed a large deviation of individual measurements of step frequency and step length from the average, while the high age group showed less deviation. These results suggested that increase in running speed was dependent on increase in step frequency and increase in step length. Furthermore high age group learned the basic form of running.
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  • Yoshiyuki KOBAYASHI, Hiroshi IZUMIKAWA, Hiroshi FUJIMOTO
    2010 Volume 34 Issue 4 Pages 317-324
    Published: 2010
    Released on J-STAGE: April 15, 2016
    JOURNAL FREE ACCESS
    Present study focused on the effect of approaching directions for stepping over an obstacle. Ten young adults were asked to head towards an obstacle from seven directions (+60, +40, +20, 0, -20, -40, and -60 degrees), and step over it. In each trial, one of the three obstacles with different heights (25mm, 50mm, and 150mm) were placed. Participants repeated the movement against each obstacle condition 5 times for a total of 105 trials. Kinematics while the participants step over the obstacles were recorded using 3-D motion capturing system, and were compared using the following parameters among the conditions: toe clearances, step length, step width, and walking speed. The results revealed that the approaching direction to the obstacles does not critically affect the obstacle avoidance movement in regards to tripping, but may critically affect the movements in regards to loss-of-balance.
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  • Toru SAKUMA, Michiyoshi AE
    2010 Volume 34 Issue 4 Pages 325-332
    Published: 2010
    Released on J-STAGE: April 15, 2016
    JOURNAL FREE ACCESS
    The purpose of this study was to investigate effects of the trunk inclination on biomechanical parameters of gait for healthy males. Ten healthy males were asked to walk in three different trunk inclinations: (1) normal for subjects, (2) with trunk leaned 10°forward, and (3) with leaned 10°backward. The gait motion was analyzed with a Vicon 612 system and two Kistler force platforms. In the forward lean gait, increases in hip flexion and knee flexion angles were observed during the stance phase. Increases in hip extension joint torque and positive joint torque power during the stance phase were likely to contribute to keep the trunk forward and swing the lower limb. In case of the backward lean gait, increases in hip flexion, knee flexion and ankle dorsiflexion angles were observed during the stance phase. These changes observed during the stance phase compensated the position of the pelvis to offset the effect of the trunk inclination. Increases in hip flexion joint torque and negative joint torque power during the stance phase seemed to be induced by the trunk position.
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Short_Paper
  • Hai-peng TANG, Atsushi OKAMOTO, Itsuki KANAAKI, Shintaro TOYOSHIMA
    2010 Volume 34 Issue 4 Pages 333-338
    Published: 2010
    Released on J-STAGE: April 15, 2016
    JOURNAL FREE ACCESS
    The purpose of this study is to evaluate the stability of the lower limbers during high speed motion. The tests included analysis of motion in 15-second stationary stepping motions and muscle strength measurements of the hip flexion in a sitting position. The motions of 80 subjects ranging from a teenager to an elderly person were videotaped with a video camera operating at 60 Hz. The stability was evaluated by the change of coefficient of variation of the knee during the stepping motion. The coefficient of variation was calculated on the ratio of the standard deviation to the mean of peak height values the knee joint reached at each step. The result showed that a sexual distinction of stability exists in the teenaged and middle-aged group, being less stable in the female teenaged group and male middle-aged group. Stability of motion and muscle strength were not influenced by aging and muscle strength from the age of 12 to 70. Stability of motion and muscle strength showed a tendency of decline from the age of 70 in both males and females. The decline of muscle strength had an influence on the stability of motion in elderly, having reduced stability from less than 17kg in males and less than 9 kg in females. The decline of stability of motion may be an important factor explaining the fall risk of elderly during fast walking or running.
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Technical_Report
  • Sunao UCHIDA, Kenji KONISHI, Chie KUBOTA, Kensuke TAKEZAWA, Kazuma ITO ...
    2010 Volume 34 Issue 4 Pages 339-343
    Published: 2010
    Released on J-STAGE: April 15, 2016
    JOURNAL FREE ACCESS
    Non-contact sheet type movement sensor for sleep monitoring was applied to monitor collegiate long-distance runners' sleep. Recordings were made during summer camp and during autumn semester,about two weeks each throughout 24 hours. The percentage of missing data was 11.6% out of total recording time of 13 subjects. Sleep lengths during summer camp season were significantly longer. Night sleep phase during semester varied whereas those during summer camp were very fixed. Compared to wrist actigram,this sheet type sleep monitor gives less interference for athletes schedule and suitable for monitoring their sleep specially for long-term monitoring.
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