Modulation of motor unit discharge rate during submaximal contractions

2014 Fiscal Year Final Research Report

• Project/Area Number: 24500684
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Physical education
• Research Institution: Japan Women's College of Physical Education
• Principal Investigator: KAMO Mifuyu 日本女子体育大学, 体育学部, 教授 (30224702)
• Co-Investigator(Renkei-kenkyūsha): MORIMOTO Shigeru 横浜国立大学, 教育人間科学部, 教授 (70119858)
• Research Collaborator: CRESSWELL Ag The University of Queensland, School of human movement studies, Professor ; BELLETT Mj The University of Queensland, School of human movement studies
• Project Period (FY): 2012-04-01 – 2015-03-31
• Keywords: 運動単位 / 放電頻度 / 多様性

Outline of Final Research Achievements

The purpose of this study was to examine heterogeneous discharge pattern of motor units during submaximal contractions. In ramp-and-hold contractions, the discharge patterns of motor unit during the hold phase changed depending on discharge history during the ramp phase. When the subject was asked to recruit a discernible single motor unit and maintain its firing at a constant rate, the firing rates of some non-targeted motor units changed during the initial phase of the contraction, and the magnitude of surface EMG increased while the targeted motor unit maintained a constant rate. These results suggest that motor units during the initial and fatigue phase readily produce a variety of discharge pattern based on the difference of balance of synaptic input to motoneuron pool and intrinsic properties of each motoneuron.

Free Research Field

運動生理学