Navegando por Assunto "Fibra muscular"

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Acesso aberto (Open Access)
Influência da facilitação neuromuscular proprioceptiva na alteração da fibra do músculo rectus femoris vista através da eletromiografia de superfície e dinamometria analógica
(Universidade Federal do Pará, 2013-09-23) PIN, Alessandro dos Santos; SILVA FILHO, Manoel da; http://lattes.cnpq.br/2032152778116209
The PNF - Proprioceptive Neuromuscular Facilitation - is a technique that is increasingly being used in muscle training of healthy people and athletes. Studies have shown that resistance exercise, including PNF, are able to convert the trained muscle fiber type. This research aimed to verify the effectiveness of PNF in increased muscle strength and check for non-invasive methods would be indicative of conversion of muscle fiber type after training. A sample group of 22 young, female university students aged between 18 and 25 years, physically active, was divided into a control group (CG n = 10) and experimental group (EG n = 12). It was collected first the Maximum Volunteer Contraction MVC of Quadriceps muscle for analogic dynamometry and root mean square - RMS by surface electromyography (EMG) of all subjects. After the first data collecting GE conducted FNP based training in the dominant lower limb to 15 sessions in 5 weeks. Before the training sessions, new MVC and RMS data were collected of all samples. Regarding muscular strength, there was an increase in both groups, significant in CG (p< 0.01) and GE (p <0.05) for RMS and MVC time, there wasn´t significant increase in GE, but the interaction Vxt was significantly increased for this group. The results corroborate the literature by showing that muscles with a predominance of resistant fibers (fiber I / IIA) have greater contraction time with more electrical activation and that the FNP is able to type IIB fibers II A. In conclusion the training sample was efficient to increase muscle strength and EMG data presented show strong evidence of the conversion of muscle fibers trained.
Acesso aberto (Open Access)
Local inhibition of nitrergic activity in tenotomized rats accelerates muscle regeneration by increasing fiber area and decreasing central core lesions
(Universidade Federal do Pará, 2017-02) SEABRA, Aline Damasceno; MORAES, Suellen Alessandra Soares de; BATISTA, Evander de Jesus Oliveira; GARCIA, Tarcyane Barata; SOUZA, Martha Costa de; OLIVEIRA, Karen Renata Matos; SILVA, Anderson Manoel Herculano Oliveira da
Muscular atrophy is a progressive degeneration characterized by muscular proteolysis, loss of mass and decrease in fiber area. Tendon rupture induces muscular atrophy due to an intrinsic functional connection. Local inhibition of nitric oxide synthase (NOS) by No-nitro-L-arginine methyl ester (L-NAME) accelerates tendon histological recovery and induces functional improvement. Here we evaluate the effects of such local nitrergic inhibition on the pattern of soleus muscle regeneration after tenotomy. Adult male Wistar rats (240 to 280 g) were divided into four experimental groups: control (n=4), tenotomized (n=6), vehicle (n=6), and L-NAME (n=6). Muscular atrophy was induced by calcaneal tendon rupture in rats. Changes in muscle wet weight and total protein levels were determined by the Bradford method, and muscle fiber area and central core lesion (CCL) occurrence were evaluated by histochemical assays. Compared to tenotomized (69.3±22%) and vehicle groups (68.1%±17%), L-NAME treatment induced an increase in total protein level (108.3±21%) after 21 days post-injury. A reduction in fiber areas was observed in tenotomized (56.3±1.3%) and vehicle groups (53.9±3.9%). However, L-NAME treatment caused an increase in this parameter (69.3±1.6%). Such events were preceded by a remarkable reduction in the number of fibers with CCL in L-NAME-treated animals (12±2%), but not in tenotomized (21±2.5%) and vehicle groups (19.6±2.8%). Altogether, our data reveal that inhibition of tendon NOS contributed to the attenuation of atrophy and acceleration of muscle regeneration.