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Please use this identifier to cite or link to this item: http://hdl.handle.net/10723/3135

Title: Behavior of human m. gastrocnemius during explosive stretch-shortening cycle movement investigated by ultrasonography
Authors: KUROKAWA, Sadao
Keywords: Ultrasonography
Muscle-tendon complex
Gastrocnemius
Elastic energy
Stretchshortening cycle
Issue Date: 31-Mar-2008
Publisher: 明治学院大学教養研究センター
Abstract: In vivo dynamics of fascicles and tendinous structures of human m. gastrocnemius medialis (MG) was investigated using ultrasonography during the stretchshortening cycle movement. Eight male subjects performed drop jumping (DJ: typical stretch shortening movement) from the height of 0.2m. During the downward phase, fascicles shortened by 7.1mm (10.6% relative to the length in the erect standing position) with 25.0mm (6.8%) of stretch in the tendinous structures although the muscle-tendon complex (MTC) lengthened by 17.0mm (4.0%) . During the upward phase, the fascicles shortened only by 3.1mm (4.7%) while the MTC rapidly shortened by 24.0mm (6.5%). Elastic energy stored in the tendinous structures during the downward phase (7.6 ± 0.45J) was partly provided from the work performed by the fascicles (2.6 ± 0.39J). In the following upward phase, 76% of the elastic energy stored in the tendinous structures (5.8 ± 0.6J) was reutilized, which accounted for 75% of the mechanical work performed by the MTC. The present results demonstrate that the fascicles operated not as a work generator, but as a force controller. Rapid recoil of the tendinous structures enhanced the shortening velocity of the MTC, which allowed the muscle fibers to behave in a quasi-isometric manner in the upward phase. In addition, it was suggested that potentiation of the contractile machinery or stretch reflexes may not be contributing to the motion generation during the DJ performed in this study.
Description: 【論文/Articles】
URI: http://hdl.handle.net/10723/3135
ISSN: 1881-8099
Appears in Collections:02巻1号(2008年3月)

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