title: Post-immobilization eccentric training promotes greater hypertrophic and angiogenic responses than passive stretching in muscles of weanling rats.
abstract: This study investigated how different types of remobilization after hind limb immobilization, eccentric exercise and passive static stretching, influenced the adaptive responses of muscles with similar function and fascicle size, but differing in their contractile characteristics. Female Wistar weanling rats (21 days old) were divided into 8 groups: immobilized for 10 days, maintaining the ankle in maximum plantar flexion; immobilized and submitted to eccentric training for 10 or 21 days on a declining treadmill for 40min; immobilized and submitted to passive stretching for 10 or 21 days for 40min by maintaining the ankle in maximum dorsiflexion; control of immobilized; and control of 10 or 21 days. The soleus and plantaris muscles were analyzed using fiber distribution, lesser diameter, capillary/fiber ratio, and morphology. Results showed that the immobilization reduced the diameter of all fiber types, caused changes in fiber distribution and decreased the number of transverse capillaries in both muscles. The recovery period of the soleus muscle is longer than that of the plantaris after detraining. Moreover, eccentric training induced greater hypertrophic and angiogenic responses than passive stretching, especially after 21 days of rehabilitation. Both techniques demonstrated positive effects for muscle rehabilitation with the eccentric exercise being more effective.
authors.affiliation: Skeletal Muscle Structure and Function, Laboratory of Scientific Research, Department of Biomechanics, Medicine and Rehabilitation of the Locomotor Apparatus, Faculty of Medicine of Ribeirão Preto, University of São Paulo, Ribeirão Preto, Brazil.
authors.forename: Priscila Cação Oliveira
authors.initials: PC
authors.lastname: Benedini-Elias
authors.affiliation: Skeletal Muscle Structure and Function, Laboratory of Scientific Research, Department of Biomechanics, Medicine and Rehabilitation of the Locomotor Apparatus, Faculty of Medicine of Ribeirão Preto, University of São Paulo, Ribeirão Preto, Brazil.
authors.forename: Mariana Calvente
authors.initials: MC
authors.lastname: Morgan
authors.affiliation: Skeletal Muscle Structure and Function, Laboratory of Scientific Research, Department of Biomechanics, Medicine and Rehabilitation of the Locomotor Apparatus, Faculty of Medicine of Ribeirão Preto, University of São Paulo, Ribeirão Preto, Brazil.
authors.forename: Anabelle Silva
authors.initials: AS
authors.lastname: Cornachione
authors.affiliation: Department of Social Medicine, Faculty of Medicine of Ribeirão Preto, University of São Paulo, Ribeirão Preto, Brazil.
authors.forename: Edson Z
authors.initials: EZ
authors.lastname: Martinez
authors.affiliation: Skeletal Muscle Structure and Function, Laboratory of Scientific Research, Department of Biomechanics, Medicine and Rehabilitation of the Locomotor Apparatus, Faculty of Medicine of Ribeirão Preto, University of São Paulo, Ribeirão Preto, Brazil. Electronic address: acms@fmrp.usp.br.
authors.forename: Ana Claudia
authors.initials: AC
authors.lastname: Mattiello-Sverzut
mesh_terms: D000818:Animals; D002196:Capillaries / Q000473:pathology / Q000503:physiopathology; D005260:Female; D006614:Hindlimb / Q000098:blood supply*; D019417:Hindlimb Suspension; D052580:Muscle Stretching Exercises; D018482:Muscle, Skeletal / Q000098:blood supply / Q000473:pathology / Q000503:physiopathology; D009133:Muscular Atrophy / Q000473:pathology / Q000503:physiopathology / Q000628:therapy*; D018919:Neovascularization, Physiologic; D010805:Physical Conditioning, Animal; D017208:Rats, Wistar
keywords: Eccentric exercise; Immobilization; Morphology; Plantaris muscle; Rat; Soleus muscle; Stretching