TITLE:
Muscle damage and regeneration: Response to exercise training
AUTHORS:
Teet Seene, Priit Kaasik
KEYWORDS:
Skeletal Muscle; Regeneration Capacity; Resistance; Endurance and Overtraining
JOURNAL NAME:
Health,
Vol.5 No.6B,
June
27,
2013
ABSTRACT:
Exercise training
influences the function of skeletal muscle, modifying fibre structure, metabolism
and promoting the release of growth factors and other signalling molecules. The number of satellite cells under
the basal lamina of type I and type IIA muscle fibres increases during endurance
training and under the basal lamina of both type II fibres during resistance training. An increase in satellite
cells is related to several factors
expressing different genes and type II muscle fibre hypertrophy. Insulin-like
growth factor-I has a role in the hypertrophy of muscle fibres through the
stimulation of the differentiation of satellite cells. The increased mitochondrial biogenesis via adenosine myophosphate-activated protein kinase is
accompanied by the suppression of myofibrillar protein synthesis through
pathways mediated by mitogen-activated protein kinases and the nuclear factor
kappa B. Insulin-like growth factor-I expression
is higher in type I fibres. Myostatin, the expression inhibitor of
muscle hypertrophy, is higher in type II fibres.
The proteasome-, lysosome- and Ca2+-mediated protein
degradation is more intensive in fibres with higher oxidative capacity. Both,
oxidative capacity and satellite cells number in muscle fibres play
important roles in skeletal muscle regeneration. In this review, we explore
the regeneration capacity changes in different types of skeletal muscle fibres
in response to resistance, endurance and overtraining.