Análisis del eje instantáneo de rotación del movimiento de flexo-extensión del cuello mediante video análisis: fiabilidad y análisis de errores

Abstract

espanolEl objetivo del trabajo es evaluar la fiabilidad para medir el eje de rotacion instantaneo (EIR) del raquis cervical de sujetos sanos mediante una tecnica de video analisis de bajo coste y disenar una tecnica que minimice los errores. Los datos fueron obtenidos a partir de marcadores tecnicos y anatomicos ubicados en 7 sujetos sanos, con tres sesiones experimentales por sujeto, medidas por dos operadores distintos. El movimiento se registro mediante la camara de video de un smartphone, a 30 fps. Los videos fueron analizados mediante el software libre Tracker, y los calculos cinematicos (posiciones, velocidades, aceleraciones y EIR) se realizaron con rutinas de programacion en MATLAB. Se realizo un analisis de fiabilidad calculando el coeficiente de correlacion intraclase (ICC) y el error estandar medio (SEM) entre operador y entre sesion. Los valores obtenidos para el SEM e ICC son aceptables y buenos, demostrando la validez del uso de tecnicas de bajo coste en aplicaciones biomecanicas, lo que abre posibilidades muy interesantes en campos como la valoracion funcional. EnglishThe objective of this work is to evaluate the reliability of the measurement of the instantaneous axis of rotation (EIR) of the cervical spine by means of a video analysis technique of low cost, as well as to design a technique that minimizes the errors. The information was obtained from technical and anatomical markers located in 7 healthy subjects, with three experimental sessions for subject, measured by two different operators. The movement registered by means of the video camera of a smartphone, to 30 fps. The videos were analyzed by means of the free software Tracker, and the kinematic calculations (positions, speeds, accelerations and EIR) were realized by proper software developed in MATLAB. A reliability analysis was realized calculating the intraclass correlation coefficient (ICC) and the standard error mean (SEM) between operator and between sessions. The values obtained for the SEM and ICC are acceptable or good, showing the possibilities of the use of techniques of low cost in biomechanical applications, what opens very interesting possibilities in fields like the functional assessment.