Acta Ortopédica Brasileira (Jan 2009)
Recuperação mecânica muscular com laser Muscular mechanical recovery with laser
Abstract
OBJETIVO: Avaliamos a influência da irradiação a laser, associada ou não a imobilização, nas propriedades mecânicas do músculo gastrocnêmio submetido à lesão experimental. MÉTODOS: Foram utilizadas 70 ratas (Wistar), divididas em 7 grupos: grupo 1- controle; grupo2 - lesão; grupo3 - lesão-irradiação laser; grupo 4 - lesão-imobilização 24 horas-irradiação laser; grupo 5 - lesão- imobilização 72 horas-irradiação laser; grupo 6 - lesão-imobilização 24 horas; grupo 7 - lesão-imobilização 72 horas. Os músculos foram submetidos a ensaios mecânicos de tração e, utilizando gráficos carga x alongamento calculadas as propriedades mecânicas no limite de proporcionalidade e no limite máximo. RESULTADOS: A lesão provocou diminuição da carga nos limites máximo e de proporcionalidade em relação ao grupo1 (pOBJECTIVE: We evaluated the influence of low-power laser irradiation, either associated or not with immobilization, on the mechanical properties of the gastrocnemius muscle submitted to experimental injury with an impact mechanism. METHODS: Seventy female Wistar rats were divided into 7 experimental groups: group 1 - control; group 2 - injury; group 3 - injury-laser irradiation; group 4 - injury-immobilization for 24-hour laser irradiation; group 5 - injury-immobilization for 72-hour laser irradiation; group 6 - injury-immobilization for 24 hours; group 7 - injury-immobilization for 72 hours. The IBRAMED® Laserpulse equipment (670 nm) was used for biostimulation. The muscles were submitted to mechanical assays in an EMIC® universal testing machine and load x stretching graphs were used to calculate the mechanical properties, i.e., at the proportionality limit and maximum limit. RESULTS: The injury provoked a reduction of load at the proportionality limit and at the maximum limit compared to group 1 (p< 0.05). Groups 2, 4, 5 and 7 differed significantly from group 1. The property of stretching at the proportionality limit differed significantly between group 1 and groups 4, 5, 6 and 7 and between groups 2 and 4. The property of stretching at the maximum limit differed between groups 1 and 5 and between groups 3 and 5. CONCLUSION: The association of immobilization for 24 and 72 hours with laser therapy did not improve the mechanical properties of the muscle, whereas the separate use of each treatment modality was more effective.
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