| Budget Amount *help |
¥18,070,000 (Direct Cost: ¥13,900,000、Indirect Cost: ¥4,170,000)
Fiscal Year 2014: ¥4,940,000 (Direct Cost: ¥3,800,000、Indirect Cost: ¥1,140,000)
Fiscal Year 2013: ¥5,070,000 (Direct Cost: ¥3,900,000、Indirect Cost: ¥1,170,000)
Fiscal Year 2012: ¥8,060,000 (Direct Cost: ¥6,200,000、Indirect Cost: ¥1,860,000)
|
|---|
| Outline of Final Research Achievements |
Molecular mechanisms underlying active stiffness (AS) and passive stiffness (PS) of human skeletal muscle were investigated in vivo, by using supersonic shear-wave measurements. In isometric contractions, AS was proportional to both the activation level of muscle and the amount of overlap between thick and thin filaments. In isotonic contractions, the ratio between contractile force and AS (force/AS) was larger under the eccentric condition than under the concentric condition. Muscular fatigue caused changes in the relationship between AS and EMG amplitude apparently in a fiber type dependent fashion. Sustained muscular tone with low activation level caused a slight increase in PS, whereas repeated dynamic contractions caused a transient decrease in PS. These results suggest that muscular stiffness is mainly originated from interactions between actin and myosin and its quantification in vivo is useful to investigate the state of muscle during a variety of human movements.
|
