ERIK: an isokinetic exercise device for the lower limbs

Abstract

In the current study, we tested a prototype of an isokinetic exercise device for the lower limbs, named the ERIK. The ERIK enables a type of single-limb squat exercise with a translational load on the swing leg in a closed kinetic chain, putting load on the muscles of the stance leg in the standing position. This training applies load to the gluteal muscles, which is effective for avoiding excessive knee valgus moment, a major factor in anterior cruciate ligament injuries. To enhance the quality of the load, an electro-rheological (ER) fluid brake system is implemented in the ERIK. The ER brake can reversibly control resistive torque with a rapid response. This paper reports a prototype of the device with four training modes, verifying its performance through basic experiments. Although high resistance is created within a wide motion area and requires isokinetic training by controlling the velocity of the trainee’s legs, the ERIK has the advantage of a high level of safety because of its passive resistive function.