muscle
• hypertrophic growth of type II fast fibers and atrophy of type I slow fibers in soleus muscle
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• soleus muscle type I slow fibers are small-sized
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• approximate 40% decrease in the cross-sectional area of type I slow fibers
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• atrophy of type I slow fibers in soleus muscle
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• the cross-sectional area of fast type II muscle fibers from soleus muscles is increased by about 47%
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• soleus muscle type I slow fibers are characterized by centrally nucleated fibers
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• loss of type I slow fibers in the adult soleus and diaphragm muscle resulting in a switch to nearly pure fast fiber muscle
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• soleus muscle shows decreased fatigue tolerance with impaired recovery
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• the time for maximum force development during twitch contraction is shorter in soleus muscles, however contractile velocity is normal
• force-frequency analysis shows that at low stimulation frequency of 40 Hz, force production is soleus muscles is lower than in controls
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• relaxation velocity of twitch and tetanic contractions are accelerated in soleus muscles
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