Hiroko Tanabe

Publications (2)3.99 Total impact

• Article: Large postural fluctuations but unchanged postural sway dynamics during tiptoe standing compared to quiet standing.

  Hiroko Tanabe, Keisuke Fujii, Motoki Kouzaki
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  ABSTRACT: The purpose of this study was to detect the characteristics of center of pressure (COP) movement during tiptoe standing (TS) compared to quiet standing (QS). Eight healthy subjects were asked to perform QS and TS on a force platform. During standing, surface electromyograms (EMGs) were recorded from the soleus (SOL), flexor hallucis brevis (FHB), medial gastrocnemius (MG), lateral gastrocnemius (LG), and tibialis anterior (TA) muscles. The path length and rectangular area of the COP trajectory were significantly larger during TS than during QS. In contrast, irrespective of standing condition, the scaling coefficients in the short and long regions were above and below 0.5, respectively. The coherence spectrum between the COP and EMG from the SOL and FHB muscles was statistically significant during TS at frequencies up to 17Hz, while that for the QS was only significant below 1Hz. In conclusion, the control of COP movement during TS was similar to that during QS despite large COP fluctuations during TS. Our results suggest that unstable posture during TS is compensated for by the activities of the SOL and FHB muscles, which enhance postural control.
  Journal of electromyography and kinesiology: official journal of the International Society of Electrophysiological Kinesiology 06/2012; · 2.00 Impact Factor
• Article: Index finger position fluctuations reflect multi-muscle coordination.

  Kaori Nagata, Shota Hagio, Hiroko Tanabe, Motoki Kouzaki
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  ABSTRACT: We hypothesized that movement fluctuations in the index finger reflect the integrated result of the coordination of multiple muscles because index finger movements are determined by the cooperation of multiple muscles spanning the metacarpophalangeal (MCP) joint. To evaluate this hypothesis, the aim of the present study was to examine the fluctuations of the index finger in abduction-adduction and extension-flexion directions during a position-holding task using two laser displacement sensors. Eleven healthy men maintained their index finger position while supporting a load at 5% of the maximal voluntary contraction force. To maintain the position of the index finger, displacement of the index finger in the abduction-adduction and extension-flexion directions was measured from a distance with two laser displacement sensors that were positioned to the lateral side of and above the index finger. The index finger movements fluctuated around the target position in not only the abduction-adduction direction but also the extension-flexion direction. The path length of finger displacement and the standard deviation of finger acceleration were significantly greater in the extension-flexion direction than in the abduction-adduction direction. These results suggest that the index finger movements quantified by two laser displacement sensors reflect the coordination of multiple muscles spanning the MCP joint.
  Journal of electromyography and kinesiology: official journal of the International Society of Electrophysiological Kinesiology 02/2012; 22(4):546-52. · 2.00 Impact Factor