Effect of cycle ergometer using an Mr rotary brake on lower limb exercise

In this study, a new cycle ergometer system using a magneto-rheological (MR) rotary brake was developed to improve muscular strength and reduce asymmetric pedaling characteristics for the rehabilitation of hemiplegia patients. For evaluation of this cycle ergometer, the characteristics of lower limb muscles were analyzed according to three factor of cycle system with MR rotary brake: (1) the electrical current of MR rotary brake, (2) the intensity and duration of cycling, (3) the application of visual feedback. The results showed that muscle activity was significantly different for various levels of current applied to the MR rotary brake. A higher current was associated with a higher integrated electromyography (IEMG) of the lower limb muscle. In low-intensity and long-term condition, IEMG of RF, TA, VL and VAS increased in the late stage of exercise (compared to the early stage), however, decreased in high-intensity and short term condition. The asymmetry of pedaling between the dominant and non-dominant leg was 19.63% in the non-visual feedback mode and 1.97% in the visual feedback mode. Therefore, our new cycle system using an MR brake with real time control of mechanical resistance can be used to enhance muscle strength in patients with hemiplegia and elderly people. Increased muscular activity of the lower limbs in patients with hemiplegia and the elderly is expected with low-intensity training over a long-term period.