Efeito do laser vs LED na região do infravermelho próximo sobre a atividade muscular esquelética: estudo clínico / Effect of laser vs LED in the near infrared region on the skeletal muscle activity: clinical study

INTRODUÇÃO: Estudos têm demonstrado a efetividade do laser no infravermelho (IV) sobre a atividade musculoesquelética. Contudo, não foram observados estudos sobre os efeitos da radiação emitida por um LED (Light Emitting Diode) no IV sobre a atividade do músculo masseter (MM, importante músculo da mastigação), sendo este o objetivo do presente estudo. MÉTODOS: Participaram do estudo 10 voluntários, os quais foram analisados por eletromiografia (atividade muscular, força e tempo de fadiga) e nível de lactato sanguíneo (mmol/L) após terapia placebo, laser (GaAlAs, 780 nm) e LED (GaAlAs, 880 nm). Os sinais obtidos previamente antes de realizadas as terapias foram tidos como controle. Os parâmetros de irradiação (laser ou LED) foram: potência de saída de 0,02 W, densidade de energia de 4 J/cm², área do feixe de 0,2 cm². Foram irradiados 8 pontos sobre o MM, de forma perpendicular e transcutânea, com distância de 1 cm entre os pontos. RESULTADOS: A atividade muscular foi significativamente maior pós-terapia laser e LED em relação aos valores controle. Não foram encontradas diferenças significativas nos valores de força, tempos de fadiga e níveis de lactato sanguíneo pós-terapia placebo, laser ou LED, quando comparados aos valores controle. CONCLUSÃO: Os resultados obtidos no presente estudo sugerem a otimização da atividade muscular com uso de terapia laser ou LED, sem causar efeitos colaterais, como a elevação de força e aumento dos níveis de lactato.

INTRODUCTION: Studies have demonstrated the effectiveness of the infrared laser (IR) on the skelet al muscle activity. However, it was not found studies on the effects of radiation emitted by IR LED (Light Emitting Diode) on the activity of masseter muscle (MM, important muscle of mastication), the aim of the present study. METHODS: Ten volunteers were involved and their electromyography (muscle activity, strength and fatigue time) and blood lactate levels (mmol/L) were analyzed after placebo, laser (GaAlAs, 780 nm) and LED (GaAlAs, 880 nm) therapies. The signals obtained previously conducted before the therapies were taken as control. The irradiation parameters (laser or LED) were: output power of 0.02 W, energy density of 4 J/cm² and beam area of 0.2 cm². Eight points on the MM were irradiated in a perpendicular and transcutaneous form with a 1-cm distance between the points. RESULTS: Muscle activity was significantly higher after laser and LED therapies when compared to control. No significant differences were found in force, fatigue time and blood lactate levels after placebo therapy, laser or LED, when compared to control. CONCLUSION: The results suggest the optimization of muscle activity with the use of laser or LED therapy, without causing side effects such as the increase in the force and levels of lactate.

Trapezius upper portion trigger points treatment purpose in positional release therapy with electromyographic analysis.

BACKGROUND: This quantification process is made through electromyography analysis. This technique of analysis is able to provide a general view of the tension decrease in the superior muscle fibers of the trapezius after therapy. AIMS: The focus of the present work is to evaluate the treatment of the cervicobrachialgia by Positional Release Therapy (PRT). MATERIAL AND METHODS: The present work studies six patients, with ages 44 to 63 (1 male and 5 female) who present tension in the trapezius upper portion fibers. All patients were submitted to 10 session of 30 minutes each. The electromyography was collected on the first and tenth day of treatment. RESULTS: The results demonstrated a progressive decrease of pain in each session. The tension was evaluated by the electromyography analysis, which showed the relations between time of treatment and less pain. CONCLUSION: With these results, it was possible to verify quantitatively the efficiency of the PRT in the improvement of life quality.

Adaptive wavelet EMG compression based on local optimization of filter banks.

This paper presents an adaptive wavelet technique for compression of surface electromyographic signals. The technique employs an optimization algorithm to adjust the wavelet filter bank in order to minimize the distortion of the compressed signal. Orthogonality of the transform is ensured by using a restriction-free parametrization described elsewhere. A case study involving real-life isotonic and isometric electromyographic signals is presented for illustration. The results show that the proposed approach outperforms the standard non-optimized wavelet technique in terms of the percent residual difference for a given compression factor.

Luz Led (640+-20nm) sobre a Atividade, Força e Tempo de fadiga do músculo masseter: estudo clínico / Light led (640+-20nm) on the Activity, Force and Time of Fatigue of muscle masseter: clinical study

O objetivo deste estudo é avaliar a atividade, força e tempo de fadiga do músculo masseter (MM), pós-irradiação com LED. Foram selecionados 30 voluntários, de ambos os sexos, com idade média de 24 anos (+-6), divididos em grupo I (6 J/cm2), II (8 J/cm2), e III (12 J/cm2), contendo 10 indivíduos por grupo. Todos os voluntários ocluíram sobre uma plataforma (célula de carga), durante 60 segundos. Realizou-se a eletromiografia dos músculos masseter durante o processo de fadiga, antes e após aplicação de LED (640+-20nm) com as diferentes doses de irradiação. Verificou ausência de diferença estatística entre a atividade, força e tempo de fadiga muscular após irradiação com as diferentes doses. Conclui-se que, na terapia com LED (640+-20nm), as doses de 6 e 8 J/cm2 são eficientes na prevenção de fadiga do MM. A dose de 12 J/cm2 não preveniu fadiga e não modificou a força muscular, não sendo indicada para esta finalidade.

The aim of this study is to evaluate the activity, strength and fatigue time of the masseter muscle followin irradiation with LED. There were selected 30 subjects, of both genders, with average age of 24 (+-6), separated into group I (6J/cm2), II (8J/cm2) and III (12J/cm2), with 10 individuals per group. All subjects chewed over a platform (load cell) during 60 seconds. We proceeded with electromyographic analysis of the masseter during the fatigue process, before and after LED application (640+-20nm) with different irradiation doses. There was found absence of statistical difference on activity, strength and muscle fatigue time after irradiation with the different doses. The conclusion eas that the LED (640+-20 nm) therapy used in this study was effective in muscle fatigue prevention with doses 6 and 8 J/cm2, but not altered with dose 12 J/cm2.