title: Acute effects of stretching exercise on the soleus muscle of female aged rats.
abstract: It has been shown that stretching exercises can improve the flexibility and independence of the elderly. However, although these exercises commonly constitute training programs, the morphological adaptations induced by stretching exercises in aged skeletal muscle are still unclear.
  
  
  OBJECTIVE
  To assess the acute effects of passive mechanical static stretching on the morphology, sarcomerogenesis and modulation of important components of the extracellular matrix of the soleus muscle of aged female rats.
  
  
  METHODS
  Fifteen old female rats with 26 months were divided into two groups: stretching (n=8, SG) and control (n=7, CG): The stretching protocol consisted of 4 repetitions each of 1 min with 30s interval between sets. Stretching was performed on the left soleus muscle, 3 times a week for 1 week. After three sessions, the rats were anesthetized to remove the left soleus muscle, and then euthanized. The following analyses were carried out: muscle fiber cross-sectional area and serial sarcomere number; immunohistochemistry for the quantification of collagen I, III and TGFβ-1.
  
  
  RESULTS
  a decrease in muscle fiber cross-sectional area of the SG was observed when compared to the CG (p=0.0001, Kruskal-Wallis); the percentage of type I collagen was significantly lower in the SG when compared to the CG (p=0.01, Kruskal-Wallis), as well as the percentage of TGFβ-1 (p=0.04, Kruskal-Wallis); collagen III was significantly higher in the SG than in the CG (7.06±6.88% vs 4.92±5.30%, p=0.01, Kruskal-Wallis).
  
  
  CONCLUSIONS
  Although the acute stretching induced muscle hypotrophy, an antifibrotic action was detected.
authors.affiliation: Physiotherapy Department, Pontifical Catholic University of Parana, Curitiba, Paraná, Brazil. Electronic address: talita.gnoato@gmail.com.
authors.forename: Talita Gnoato
authors.initials: TG
authors.lastname: Zotz
authors.affiliation: Health Science Program, Pontifical Catholic University of Paraná, Curitiba, Paraná, Brazil.
authors.forename: Luiz Guilherme A
authors.initials: LG
authors.lastname: Capriglione
authors.affiliation: Vivarium Department, Pontifical Catholic University of Parana, Curitiba, Paraná, Brazil.
authors.forename: Rafael
authors.initials: R
authors.lastname: Zotz
authors.affiliation: School of Medicine - Experimental Pathology Laboratory, Masters and Doctorate Programs in Health Science of the Pontifical Catholic University of Paraná, Curitiba, Paraná, Brazil.
authors.forename: Lucia
authors.initials: L
authors.lastname: Noronha
authors.affiliation: Experimental Pathology Department, Pontifical Catholic University of Paraná, Curitiba, Paraná, Brazil.
authors.forename: Marina Louise
authors.initials: ML
authors.lastname: Viola De Azevedo
authors.affiliation: Physical Education Department, Federal University of Paraná, Curitiba, Paraná, Brazil.
authors.forename: Hilana Rickli
authors.initials: HR
authors.lastname: Fiuza Martins
authors.affiliation: Physiotherapy Department, Masters and Doctorate Programs in Physical Education, Federal University of Paraná, Curitiba, Paraná, Brazil.
authors.forename: Anna Raquel
authors.initials: AR
authors.lastname: Silveira Gomes
mesh_terms: D000375:Aging; D000818:Animals; D005260:Female; D052580:Muscle Stretching Exercises; D018482:Muscle, Skeletal / Q000473:pathology / Q000502:physiology*; D009929:Organ Size; D001678:Organelle Biogenesis; D016059:Range of Motion, Articular; D017208:Rats, Wistar; D012518:Sarcomeres / Q000473:pathology / Q000502:physiology; D055948:Sarcopenia / Q000517:prevention & control*
keywords: Collagen; Elderly female rats; Extracellular matrix; Muscle stretching exercises; Musculoskeletal system; Sarcopenia