Eccentric exercise training as a countermeasure to non-weight-bearing soleus muscle atrophy.
Although various exercise paradigms have been tested, none has completely prevented muscle atrophy during non-weight bearing. Because loaded eccentric contractions occur during normal daily activity but are absent during non-weight bearing, this investigation tested whether eccentric resistance training could prevent soleus muscle atrophy during non-weight bearing. Adult female rats were randomly assigned to either weight bearing +/- intramuscular electrodes or non-weight bearing +/- intramuscular electrodes groups. Electrically stimulated maximal eccentric contractions (4 sets of 6 repetitions at approximately 0.2 fiber lengths/s, 128 degrees range of motion) were performed on anesthetized animals at 48-h intervals during the 10-day experiment. Non-weight bearing significantly reduced soleus muscle wet weight (28-31%) and noncollagenous protein content (30-31%) compared with controls. Eccentric exercise training during non-weight bearing attenuated but did not prevent the loss of soleus muscle wet weight and noncollagenous protein by 77 and 44%, respectively. The potential of eccentric exercise training as an effective and highly efficient counter-measure to non-weight-bearing atrophy is demonstrated in the 44% attenuation of soleus muscle noncollagenous protein loss by eccentric exercise during only 0.035% of the total non-weight-bearing time period.
Kirby
C R
CR
Department of Physiology and Cell Biology, University of Texas Medical School, Houston 77225.
Ryan
M J
MJ
Booth
F W
FW
D000311:Adrenal Glands / Q000502:physiology; D000818:Animals; D001284:Atrophy; D001835:Body Weight / Q000502:physiology; D004567:Electrodes, Implanted; D005260:Female; D009119:Muscle Contraction / Q000502:physiology; D009124:Muscle Proteins / Q000096:biosynthesis; D009132:Muscles / Q000473:pathology*; D009929:Organ Size / Q000502:physiology; D010805:Physical Conditioning, Animal; D051381:Rats; D017207:Rats, Sprague-Dawley; D014893:Weightlessness / Q000009:adverse effects*
D009124:Muscle Proteins