In vivo passive mechanical properties of the human gastrocnemius muscle belly

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• 作者：Muraoka ; Tetsuro ; Chino ; Kentaro ; Muramatsu ; Tadashi ; Fukunaga ; Tetsuo ; Kanehisa ; Hiroaki
• 关键词：Ultrasonography ; Muscle fascicle length ; Biarticular muscle
• 刊名：Journal of Biomechanics
• 出版年：2005
• 出版时间：June, 2005
• 年：2005
• 卷：38
• 期：6
• 页码：1213-1219
• 全文大小：388 K

文摘

The purpose of the present study was to determine the in vivo passive mechanical properties, including the length below the slack length, of the gastrocnemius muscle (GAS) belly in humans. Transverse ultrasound images of the medial head of the GAS were taken in 11 subjects during passive knee extension from 80° to 5° with a constant ankle joint angle of 10° (0° is the neutral ankle position: positive values for dorsiflexion). The change in passive ankle joint moment (Mp), which is produced only by the GAS length change, was also measured during passive knee extension. The onset of Mp during passive knee extension was found to be 43±8° (mean±SD) when the baseline of the Mp was set at the average Mp in the range of 55–60° where the Mp was almost constant (). At this onset, the muscle fascicle length of the GAS (Lf) was (slack length; Lfs). Lf at 80° was (13±6 % ) less than the Lfs, and Lf at 5° was (27±11 % ) greater than the Lfs. The passive force-resisting compression of the GAS did not produce a dorsiflexion moment in the joint angle range adopted. The passive ankle joint moment increased linearly with Lf (coefficient of determination (R²)=0.85–0.96), and the slopes of the relationships between Lf and Mp, and between the relative Lf to Lfs and Mp were and . The findings of the present study can be implemented in musculoskeletal modeling, which would provide a more accurate evaluation of the passive mechanical properties of muscle during movement.