ABSTRACT
Introducción: La manipulación vertebral se relaciona con el aumento de la fuerza muscular, aunque no existen suficientes evidencias relativas a su aplicación en el raquis cervical. Objetivo: Determinar los efectos inmediatos de la técnica de manipulación de C5/C6 (Ashmore) en la actividad electromiográfica en reposo y en las contracciones del músculo deltoides medio bilateralmente. Material y Métodos: Estudio experimental, aleatorizado, cegado y controlado. Treinta (n=30) pacientes con Cervicalgia Mecánica (CM) se distribuyeron aleatoriamente en dos grupos, experimental (GE; n=15) y control (GC; n=15). Los pacientes fueron evaluados mediante el cuestionario Neck Disability Index (NDI), el test de la arteria vertebral y electromiografía (EMG) antes de la intervención. Después de las intervenciones en los grupos de estudio, realizamos otra vez la prueba EMG. Resultados: Los análisis comparativos intergrupos post-intervención presentaron diferencias estadísticamente significativas para las variables Root Mean Square (RMS) en isometría de 30 segundos bilateral, para el músculo deltoides medio. Conclusiones: La manipulación vertebral C5-C6 disminuye la actividad electromiográfica en la contracción isométrica, pero no produce cambios electromiográficos en reposo ni en contracción isotónica (AU)
Introduction: The effects of spinal manipulation are not yet entirely clear. Previous studies have found both increased and decreased electromyographic (EMG) activity of muscles related to the level being manipulated, although few of them have considered the cervical region or symptomatic individuals. Objetives: To determine the immediate effects of the C5/C6 (Ashmore) manipulation technique on bilateral EMG activity of the middle deltoid muscle at rest and in contractions. Patients, Materials and Methods: A randomized, controlled, single blind, experimental study was conducted. A total of 30 individuals presenting with mechanical neck pain were assigned randomly to two groups: 15 formed the experimental group (EG), and 15 the control group (CG). All participants completed a data questionnaire and the NDI (Neck Disability Index), and underwent a vertebral artery and EMG evaluation before their participation. After C5/C6 manipulation in the intervention group and no manipulation in the control group, the EMG evaluation was repeated. Results: All the variables were normally distributed, indicative of the total sample's initial homogeneity. Comparative post-intervention inter-group analyses showed statistically significant differences in the root mean square (RMS) values of the 30-s isometric bilateral EMG measurements of the middle deltoid muscle's activity. Conclusions: C5-C6 spinal manipulation reduced EMG activity in the longer isometric contractions, but no changes were observed neither in the resting EMG values nor in the isotonic contractions performed(AU)
