Language：English   Publishing type：Research paper (scientific journal)

Pole walking (PW) has received attention not only as a whole-body exercise that can be adapted for elderly people with poor physical fitness but also as a possible intervention for the restoration of gait function in normal walking without the use of poles (i.e., conventional walking CW). However, the characteristics of PW, especially how and why PW training affects CW, remain unclear. The purpose of this study was to examine the characteristics of locomotor adaptation in PW from the perspective of kinematic variables. For this purpose, we compared the locomotor adaptation in PW and CW to that when walking on a split-belt treadmill in terms of spatial and temporal coordination. The result showed that adaptations to the split-belt treadmill in PW and CW were found only in interlimb parameters (step length and double support time ratios (fast/slow limb)), not in intralimb parameters (stride length and stance time ratios). In these interlimb parameters, the movement patterns acquired through split-belt locomotor adaptations (i.e., the aftereffects) were transferred between CW and PW regardless of whether the novel movement patterns were learned in CW or PW. The aftereffects of double support time and step length learned in CW were completely washed out by the subsequent execution in PW. On the other hand, the aftereffect of double support time learned in PW was not completely washed out by the subsequent execution in CW, whereas the aftereffect of step length learned in PW was completely washed out by the subsequent execution in CW. These results suggest that the neural mechanisms related to controlling interlimb parameters are shared between CW and PW, and it is possible that, in interlimb coordination, temporal coordination is preferentially stored in adaptation during PW.

DOI： 10.1007/s00221-020-05954-0

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© The Author(s) 2020. The execution of cognitive tasks is known to alter postural sway during standing, but the underlying mechanisms are still debated. This study investigated how performing a mental task modified balance control during standing. We required 15 healthy adult males to maintain an upright stance under conditions of simply relaxing and maintaining normal quiet standing (control condition) or while performing a secondary cognitive task (mental arithmetic). Under each condition, we measured the participants’ center of pressure and used kinematic measurements for a quantitative evaluation of postural control modulation. We calculated the standard deviation of the joint angles (ankle, knee, and hip) and the estimated joint stiffness to measure joint mobility changes in postural control. To estimate the kinematic pattern of covariation among these joints, we used uncontrolled manifold analysis, an assessment of the strength of multijoint coordination. Compared to normal standing, executing the cognitive task while standing led to reduced movements of the ankle and hip joints. There were no significant differences in ankle stiffness or uncontrolled manifold ratios between the conditions. Our results suggest that when performing a secondary cognitive task during standing, neither changes in the modification of stiffness nor the strength of multijoint coordination (both of which preserve the center of mass position) explains changes in postural sway.

DOI： 10.1177/0031512520919543

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Language：English   Publishing type：Research paper (scientific journal)

DOI： 10.3390/sports8040046

Language：English   Publishing type：Research paper (scientific journal)

The present study was a cross-sectional comparison of probabilistic structure in the distribution of pitching location among baseball pitchers of various age groups (25 elementary school (ES), 20 junior high school (JH), 15 high school (HS), and 18 college students (CL)). In the results, despite the general age-dependent variations in pitching precision, the difference was reflected not only in error ‘size’ but also in the ‘shape’ of error as it was shown by fitting 95% confidence ellipse to the two dimensional distribution of pitch location. While the precision measure as a reflection of trial-by-trial variability of release timing (major axis length of the ellipse) was constant, minor axis length of the ellipse as a reflection of variability in the pitching form of each participant demonstrated significant differences among the groups. In the ES group particularly, the trial-by-trial variability in the trajectory angle of the throwing arm was significantly correlated with the minor axis length; this correlation was far greater than those in older groups. The present study is the first to demonstrate the detailed structure of the variability of pitching location of baseball dependent on age.

DOI： 10.1080/14763141.2020.1822908

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Authorship：Lead author   Language：English   Publishing type：Research paper (scientific journal)

DOI： 10.1007/s00221-019-05541-y

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Language：English   Publishing type：Research paper (scientific journal)

DOI： 10.1371/journal.pone.0214818

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DOI： 10.1007/s00221-018-5437-6

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DOI： 10.1007/s00221-019-05656-2

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Language：English   Publishing type：Research paper (scientific journal)

DOI： 10.1371/journal.pone.0197385

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Language：English   Publishing type：Research paper (scientific journal)

DOI： 10.1016/j.neulet.2018.01.015

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Authorship：Corresponding author   Language：English   Publishing type：Research paper (scientific journal)

DOI： 10.3389/fnhum.2018.00068

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Language：English   Publishing type：Research paper (scientific journal)

DOI： 10.1007/s00221-017-5131-0

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Authorship：Lead author   Language：English   Publishing type：Research paper (scientific journal)

DOI： 10.1016/j.jelekin.2017.12.007

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Language：English   Publishing type：Research paper (international conference proceedings)

DOI： 10.1109/EMBC.2017.8037024

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DOI： 10.1080/14763141.2017.1332236

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Language：English   Publishing type：Research paper (scientific journal)

DOI： 10.1371/journal.pone.0180275

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Language：Japanese   Publishing type：Research paper (other academic)

<p>【はじめに，目的】</p><p></p><p>運動野から脊髄運動ニューロンに下降する皮質脊髄路（CST）は，ヒト二足立位の制御に関わる神経経路の一つである。これまでの研究で，足関節底背屈筋CSTの興奮性は，不安定な環境に暴露された際に上昇することが報告されており，フィードバック情報に応じて，姿勢要求に見合うように変調していると考えられる。</p><p></p><p>一方，姿勢外乱により不安定な環境が予測される時，CSTがどのように調節されるかは明らかではない。CSTが予測情報を利用して興奮性を調節しているのであれば，予測される外乱に応じてあらかじめ応答を設定していると考えられる。</p><p></p><p>本研究の目的は，足関節底背屈筋CSTの興奮性が，外乱の方位・強度の予測情報に応じて，先行して変調するかを明らかにすることであった。</p><p></p><p></p><p>【方法】</p><p></p><p>対象は健常な成人男性12名（27.3±5.6歳）であった。経頭蓋磁気刺激装置（TMS）を用い，姿勢外乱が印加される50ms前の運動誘発電位（MEP）を計測した。参加者には，プラットフォーム上（Motion-Base MB-150）で立位姿勢を保持するように指示した。外乱は，足底支持面の前後方向への水平移動を負荷した。今回の研究では，強度および方位を変えた3種類の外乱を用いた。実験条件は，それぞれの外乱が単独で加わる①前方・弱（3.5cm，10cm/s），②前方・強（7.0cm，25cm/s），③後方（7.0cm，25cm/s）と，3種の外乱が順不同に加わる④ランダム，さらに，外乱を負荷しない⑤外乱なし，を設けた。筋活動応答を，前脛骨筋（TA），ヒラメ筋（SOL）から導出した。統計処理は，各条件で得られたMEPの差を一元配置分散分析により比較した。統計的有意水準は5%とした。</p><p></p><p></p><p>【結果】</p><p></p><p>前脛骨筋MEPは，外乱なし，後方，前方・弱，ランダム，前方・強条件の順に増大していた。分散分析の結果，前脛骨筋MEPには条件間の主効果が認められた（F_2.2 _24.7=14.9，p＜0.001）。事後解析において，後方以外の他の条件で外乱なし条件よりも有意に増大していた。またこれは外乱の強度・方位の影響を受け，前方・強条件で前方・弱および後方条件よりも有意な増大を示した。一方，ヒラメ筋MEPについては，条件間の主効果が認められなかった（F_{4 44}=2.2，p=0.09）。</p><p></p><p></p><p>【結論】</p><p></p><p>本研究の結果から，外乱の予測によってTAのCSTの興奮性が事前に変調することが明らかとなった。また，この変調は，外乱の強度および方位に応じてスケーリングされることが分かった。このことは，無意識・無自覚に調節される立位の制御においても，随意運動と同じように，予測情報を利用して中枢神経系の応答が事前設定されていることを示唆している。また，TAとSOLの間で予測の効果が異なっており，このことは立位姿勢における両筋の役割の違いや，皮質脊髄路との連絡の強さの違いを反映していると考えられる。</p>

DOI： 10.14900/cjpt.2016.0476

CiNii Article

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Language：English   Publishing type：Research paper (scientific journal)

DOI： 10.1371/journal.pone.0158721

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Language：English   Publishing type：Research paper (international conference proceedings)

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Excitability of both stretch reflex (SR) and motor evoked potential (MEP) elicited in the tibialis anterior (TA) muscle by transcranial magnetic stimulation were tested in standing humans. The results demonstrated significantly greater values for both SR and MEP in the TA while standing than while in the supine posture, although background electromyographic activity was silent in the two conditions. Taken together with previous reports that both pathways are facilitated in the TA at the early stance phase of human walking, our findings suggest that a common neural mechanism underlies both observations, one that might be functionally relevant for securing ankle joint stabilization during upright standing. © 2002 Elsevier Science Ireland Ltd. All rights reserved.

DOI： 10.1016/S0304-3940(02)01353-8

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