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DOI: 10.1055/s-2008-1026031
Adaptive Response in Human Skeletal Muscle Subjected to Prolonged Eccentric Training
Publication History
Publication Date:
14 March 2008 (online)
Abstract
The peripheral adaptation process associated with repeating eccentric training over a longer period of time was studied in m. vastus lateralis of eleven healthy males aged 24 ± 4 years. The maximal dynamic concentric muscle strength was only slightly improved after 8 weeks of training. However, eccentric work capacity was dramatically increased (375%). A maximal eccentric stint immediately after fulfilled 8 weeks of training caused a selective glycogen depletion from the type 2B fibers. An increased number of type 2C fibers was observed. The ultrastructural analysis showed an essentially well-preserved fine structure. Volume density of mitochondria was somewhat higher in all fiber types after training. Z-band widths were not affected by eccentric training. It is concluded that skeletal musculature adapts itself in a functional manner to the extreme tension demands put on them. Improved coordination and reorganization of the contractile apparatus of muscle fibers are the determining mechanisms of this adaptation.
Key words
human - eccentric training - muscle soreness - fiber types - myofibrils - histocytochemistry - ultrastructure - exertion