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.

Effects of isokinetic devices on lower limb

“…The major purpose of this type of training is to heal and/or preserve the ACL while also providing an effective way for sports strength training. [1]to improve the standard. Isotonic exercises use a constant load, isometric exercises use a constant posture, and isokinetic exercises use a constant angular velocity of the joint.…”

“…Despite the inclusion of a real-time speed control mechanism using magnetorheological fluid in a suggested stepper device, the equipment's recumbent design limited trainee postures and motion kinds. [1] Closed kinetic chain training creates a closed-loop linkage with both legs and the floor. Importantly, because this type of exercise decreases the anterior shear and valgus forces on the knee joint, it has a high level of safety.…”

“…Thus, improved training equipment is needed for isokinetic exercise, enabling easy and variable setting of the resistant force to provide acceptable levels of safety and effectiveness. [1] The ERIK has the advantage of a high level of safety in isokinetic exercise, which conventionally requires controllable actuators, such as servomotors. In addition, the ERIK can load higher resistance within a wide motion area compared with conventional equipment.…”

“…Thus, whether the isokinetic mode of the ERIK has adequate training effectiveness is confirmed in "Experimental verification" section. [1] Isokinetic dynamometers are passive devices which resist applied forces and control the speed of exercise at a predetermined rate. Such dynamometers generally provide a record of applied force throughout a joint range of motion.…”

“…Essentially, these are devices that allow for maximum muscle contraction over the entire range of joint motion. An isokinetic machine is a rehabilitative exercise device used to assess, evaluate, and promote muscular strength and joint range of motion for medical purposes [1]. An electro-rheological fluid brake sensor is implemented in the ERIK to enhance the load quality.…”