Dispositivo de resistência vibratório para treinamento muscular de membros inferiores

Abstract

The practice of sports and physical exercise in general has a major influence on people’s fitness and quality of life. In this context, it is of fundamental importance to develop low-cost muscle training/rehabilitation equipment that is efficient and accessible. The aim of this study was to design, build and test a extension/flexion machine with a cam-spring resistance system and a device for applying mechanical vibration in the direction of muscle shortening. Two identical conventional extension chairs were purchased, one of which had its resistance system replaced by a cam-spring system with mechanical vibration and the other was kept completely original to be used in the tests as a basis for comparison, with identical postural parameters. The new equipment is simple, compact, low inertia and allows mechanical vibrations to be applied in the direction of muscle shortening with adjustable frequency and amplitude. Due to its low inertia design, the equipment also allows milimetric load variation and exercises to be performed at higher speeds and with less risk of injury. The comparative tests evaluated the activation amplitude of the electromyographic signal in the right and left rectus femoris muscles of trained individuals during bilateral extension/flexion movements on the conventional chair and the new equipment. The sample consisted of 7 trained male volunteers aged between 18 and 40. The protocol consisted of 4 types of exercise: conventional machine with controlled speed (CEC), new machine with controlled speed (CAME), new machine with controlled speed and addition of mechanical vibration (VIBRA) and new machine with maximum speed (POT). A significant increase in the amplitude of the electromyographic signal was observed in the POT compared to the other exercises, both in the concentric and eccentric phases. Overall, the equipment proved to be effective, safe and with great innovative potential for improving training gains.