Brazilian Journal of Pain
Brazilian Journal of Pain
Original Article

Low-intensity resistance training promotes a reduction of mechanical hyperalgesia and increase of muscle strength in rats submitted to the diffused chronic muscle pain model

Treinamento resistido de baixa intensidade promove redução da hiperalgesia mecânica e aumento da força muscular em ratos submetidos ao modelo de dor crônica muscular difusa

André Luiz Silva Santos; Mônica Deise dos Santos Rocha; Mateus Maciel Santos; Josimari Melo DeSantana

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BACKGROUND AND OBJECTIVES: Fibromyalgia syndrome (FMS) is characterized by different factors, such as chronic diffuse muscle pain (CDMP), fatigue and psycho-emotional changes. Among the animal models that mimic FMS, the acid saline model is consolidated in the development and maintenance of CDMP. Resistance training (RT) has been an effective method for reducing pain in FMS. Thus, the aim of the present study was to evaluate the effects of resistance training on nociceptive and motor responses in an animal model of chronic diffuse muscular pain.
METHODS: Twenty-four male Wistar rats were allocated into four groups: resistance training, RT control, amitriptyline (AMITRIP) and AMITRIP control; all treatment protocols lasted 4 weeks. CDMP was induced in all mice. Then, the animals were treated with low-intensity RT (40% 1 maximum repetition) and AMITRIP (10 mg/kg/day). The mechanical paw withdrawal threshold, locomotor activity and muscle strength were evaluated.
RESULTS: Animals treated with both RT and AMITRIP showed an increase in the mechanical paw withdrawal threshold (p<0.05) compared to their controls, suggesting a reduction in mechanical hyperalgesia. There was no improvement in locomotor activity in all groups (p>0.05). Animals with CDMP that underwent RT showed an increase in hindlimb muscle strength (p<0.0001) compared to the RT control group.
CONCLUSION: Low-intensity resistance training resulted in antihyperalgesic effects and improved muscle strength in animals submitted to the CDMP model.


Exercise, Fibromyalgia, Neurosciences, Resistance training


JUSTIFICATIVA E OBJETIVOS: A síndrome da fibromialgia (SFM) é caracterizada por diferentes fatores, como dor crônica muscular difusa (DCMD), fadiga e alterações psicoemocionais. Dentre os modelos animais que mimetizam a SFM, o modelo de salina ácida é consolidado no desenvolvimento e na manutenção da DCMD. O treinamento resistido (TR) tem sido um método eficaz para redução da dor na SFM. Assim, o objetivo do presente estudo foi avaliar os efeitos do TR na resposta nociceptiva e motora em modelo animal de dor crônica muscular difusa. 
MÉTODOS: Vinte e quatro ratos machos Wistar foram alocados em quatro grupos: treinamento resistido (TR), controle do TR, amitriptilina (AMITRIP) e controle da AMITRIP, todos os protocolos de tratamento tiveram duração de 4 semanas. A DCMD foi induzida em todos os ratos. Em seguida, os animais foram tratados com TR de baixa intensidade (40% 1 repetição máxima) e AMITRIP (10 mg/kg/dia). Foram avaliados o limiar mecânico de retirada de pata, a atividade locomotora e a força muscular. 
RESULTADOS: Animais tratados tanto com TR quanto com AMITRIP apresentaram aumento do limiar mecânico de retirada de pata (p<0,05) em relação aos seus controles, sugerindo redução da hiperalgesia mecânica. Não foi observada melhora da atividade locomotora em todos os grupos (p>0,05). Animais com DCMD que realizaram TR obtiveram aumento da força muscular dos membros posteriores (p<0,0001) em comparação ao grupo controle do TR. 
CONCLUSÃO: Treinamento resistido de baixa intensidade resultou em efeitos anti-hiperalgésicos e melhora da força muscular em animais submetidos ao modelo de DCMD. 


Exercício físico, Fibromialgia, Neurociências, Treinamento de resistência


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