title: Bouts of passive stretching after immobilization of the rat soleus muscle increase collagen macromolecular organization and muscle fiber area.
abstract: This study evaluated the effect of short bouts of stretching on the soleus muscle after immobilization, by measuring the birefringence of the intramuscular connective tissue (ICT) and the muscle fiber area. Thirty rats were divided into five groups: the left soleus was immobilized in the shortened position; after immobilization the animals remained free; after immobilization, the soleus was stretched daily (10 stretches of 60 sec followed by 30 sec rest); after immobilization, the soleus was stretched 3 times a week; control. Immobilization caused a loss of birefringence of the ICT and of muscle fiber area and only daily stretching increased both compared with the control (p< 0.01). In conclusion, short daily bouts of stretching after immobilization induced molecular reorganization of the collagen bundles and muscle fiber hypertrophy in the rat soleus.
authors.affiliation: Unit of Skeletal Muscle Plasticity, Department of Physical Therapy, Federal University of São Carlos, São Carlos, SP, Brazil.
authors.forename: Eliane Lima
authors.initials: EL
authors.lastname: Coutinho
authors.forename: Camila
authors.initials: C
authors.lastname: DeLuca
authors.forename: Tania Fatima
authors.initials: TF
authors.lastname: Salvini
authors.forename: Benedito Campos
authors.initials: BC
authors.lastname: Vidal
mesh_terms: D000818:Animals; D001718:Birefringence; D049108:Cell Enlargement; D003094:Collagen / Q000737:chemistry / Q000378:metabolism*; D019417:Hindlimb Suspension / Q000502:physiology*; D006984:Hypertrophy / Q000378:metabolism; D008297:Male; D018485:Muscle Fibers, Skeletal / Q000166:cytology / Q000378:metabolism*; D052580:Muscle Stretching Exercises / Q000379:methods*; D018482:Muscle, Skeletal / Q000166:cytology / Q000378:metabolism* / Q000503:physiopathology; D009133:Muscular Atrophy / Q000503:physiopathology / Q000517:prevention & control / Q000534:rehabilitation*; D010805:Physical Conditioning, Animal / Q000379:methods / Q000502:physiology; D010812:Physical Stimulation / Q000379:methods; D051381:Rats; D017208:Rats, Wistar; D013314:Stress, Mechanical; D016896:Treatment Outcome; D015854:Up-Regulation / Q000502:physiology
chemical_list: D003094:Collagen