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Copyright of Rigakuryoho Kagaku is the property of International Press Editing Center Incorporation and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Rigakuryoho Kagaku is the property of International Press Editing Center Incorporation and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Rigakuryoho Kagaku is the property of International Press Editing Center Incorporation and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Rigakuryoho Kagaku is the property of International Press Editing Center Incorporation and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Rigakuryoho Kagaku is the property of International Press Editing Center Incorporation and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Center of pressure (COP) has been one of the most popular index for balance evaluation in quiet standing. However, the balance evaluation based on COP has been limited due to its accuracy. For accurate balance evaluation, an estimation method of the center of mass (COM) from simple measuring devices is desirable. The purpose of this study is to estimate COM on sagittal plane from force plate measurement. One of the most popular method suggested in past studies is to integrate the COM acceleration estimated from shearing force on support surface, however, this technique requires appropriate boundary conditions. Instead of the integration method, we adopted a COM estimation method via gravity term in equation of angular motion. While the method can estimate COM in real time, an estimation error arose from the assumption of a single rigid body model. To clarify the estimation error in theory, we introduced a modal coordinate (rigid body mode and zero shearing force mode) in the analysis of double-link model. As a result, we found that the estimation accuracy decreases due to the influence of acceleration of zero shearing force mode. From a practical point of view, if the amplitude of COP and the ratio of zero shearing force mode is relatively small, COM can be estimated with high accuracy. Validation of the present method was verified by comparing COM from force plate measurement with that from motion capture measurement in stationary standing test and horizontally sway test.

[Purpose] The purpose of the present study was to investigate the mechanisms of center of pressure (COP) management for initiating single leg squatting. [Participants and Methods] Nine healthy young males were categorized according to the initial anterior-posterior direction of their COP migration when initiating squatting. The COP location within the foot area, sagittal plane knee and ankle joint movements, and electromyographic activities of ankle joint muscles before and during squatting were analyzed. [Results] The COP of 5 subjects initially moved forward when initiating squatting, whereas the COP of the other 4 subjects initially moved backward. In the forward group, the COP was located in a significantly posterior position within the foot area before squatting and the EMG activities of the gastrocnemius significantly decreased after the movement started. [Conclusion] It is probable that the direction of initial COP migration depends on the COP positioning of the initial standing posture prior to initiating single leg squats. [ABSTRACT FROM AUTHOR]

Copyright of Rigakuryoho Kagaku is the property of International Press Editing Center Incorporation and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Rigakuryoho Kagaku is the property of International Press Editing Center Incorporation and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Rigakuryoho Kagaku is the property of International Press Editing Center Incorporation and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

[Purpose] The purpose of this study was to clarify the relationship between the forward displacement of the center of pressure (COP), and the weight-bearing capacity of the paretic lower extremity during sit-to-stand, and the spasticity of patients with stroke. [Subjects] Fourteen patients who were hemiplegic due to stroke participated in this study. [Methods] A foot pressure sensor was used to measure the displacement of COP and the weight bearing ratio in the paretic lower extremity during sit-to-stand movement. The spasticity of the paretic plantar flexor muscle was evaluated using the Modified Ashworth Scale (MAS). [Results] The forward displacement of COP showed a significant relationship with the weight-bearing ratio (rs = -0.60) and the MAS (rs = 0.65). [Conclusions] Our results suggest that the forward displacement of COP is caused by excessive activation of the paretic plantar flexor muscle, which results in disturbance of weight bearing by the paretic limb. [ABSTRACT FROM AUTHOR]

[Purpose] To clarify whether an increase in the hip flexion angle influences balance in the windup pitching position in baseball. [Subjects] Subjects were 12 male university baseball pitchers and 12 healthy male students with no experience of baseball. [Method] We measured the shifts in the center of pressure of the subjects. The comparison of the pitchers and the healthy men was performed at the same hip flexion angle. The pitchers were compared between the hip flexion angle of the position ready to throw the ball and the maximum possible hip flexion. [Result] The pitchers showed a significantly lower shift in the center of pressure than the healthy men (p<0.05). In pitchers, the shift in the center of pressure significantly increased at the maximum possible hip flexion angle (p<0.05). [Conclusion] Baseball pitchers had superior balance in the normal wind-up position, however their balance ability decreased at the maximum possible hip flexion angle. [ABSTRACT FROM AUTHOR]

[Purpose] The aim of this study was to reveal the interrelations between parameters of center of pressure (COP) movement, and to identify parameters showing the common features of standing balance. [Subjects] The subjects were 24 healthy adults. [Methods] We measured subjects' COP motion for 10 seconds in 4 static upright postures (opened-feet, closed-feet, Mann's posture, one-legged) selected from the Berg balance scale. [Results] Only 1 factor was identified by factor analysis in the area surrounded by the maximal amplitude rectangle (REC.AREA). For the other parameters of COP movement, 2 factors were identified. [Conclusion] REC.AREA expressed the common characteristics of standing balance, so it could be possible to evaluate standing balance by REC.AREA. [ABSTRACT FROM AUTHOR]

[Purpose] Standing balance is evaluated by center of pressure. Many kinds of parameters of center of pressure make evaluation of standing balance difficult, so we examined the interrelation between parameters of center of pressure in 5 static upright postures, to simplify evaluation of standing balance. [Subjects] Subjects were 24 healthy adults. [Methods] We measured subjects' center of pressure motion for 10 seconds during 5 static upright postures (opened-feet, closed-eyes, closed-feet, Mann's posture, one-legged). [Results] Result of factor analysis, no single factor was found that was common to all the postures. [Conclusion] It might be possible to evaluate the standing balance by one of the parameters we measured in this study. We consider that it is necessary to examine parameters which express the standing balance. [ABSTRACT FROM AUTHOR]

Copyright of Japanese Journal of Physical Fitness & Sports Medicine / Tairyoku kagak is the property of Japanese Society of Physical Fitness & Sports Medicine and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)