A Cable-Driven Portable Fitness Chair with Programmable Resistance for Effective Muscle Training.

The COVID-19 pandemic has changed the lifestyle of society and the interest in health and fitness has greatly increased, accordingly. Recently, motorized devices that allow fine and automatic adjustment of resistance without physically changing the applied weight have been released to the market. In fact, these devices have eased the resistance-changing process. However, such devices are still not portable as they must be mounted on the wall and their resistance control needs to be improved to increase the efficiency of strength training. This study introduces a portable chair-shaped fitness device that allows inducing various resistance profiles. A compact, light, and robust cable-driven actuation module design was achieved by implementing a derailing prevention mechanism. The actuator covers resistance up to 120 N for each left and right arm separately. Exercise can be conducted by pulling the elastic handle connected to cable. The controller of the proposed device allows variation of resistance according to the joint range-of-motion (ROM) to make the workout more challenging but still safe through the full ROM. Viscous resistance, ascending resistance, and descending resistance profile can be provided. The experimental results shows that various muscle activation patterns can be provided by changing the resistance profile, which is important for effective training. The device can be used anywhere, at home or office, to perform various upper and lower body exercises or for physical self-care.