Biomedical Engineering Reference
In-Depth Information
Chapter Eleven
Isokinetic Exercise Machine Using High
Performance MR Fluid Brake and
Iso-Contraction Exercise
Kunihiko Oda
∗
, Takehito Kikuchi
†
, Shiro Isozumi
‡
and Junji Furusho
‡
∗
Department of Physical Therapy, Osaka Electro-Communication University,
1130-70 Kiyotaki, Shijonawate, Osaka 575-0063, Japan
†
Graduate School of Science and Engineering, Yamagata University,
4-3-16 Jonan, Yonezawa 992-8510, Japan
‡
Graduate School of Engineering, Osaka University,
2-1 Yamadaoka, Suita, Osaka 565-0871, Japan
Isokinetic exercises used in rehabilitation to strengthen muscles often require
expensive exercise equipments. The safe isokinetic exercise system we developed
uses only brakes with a magnetorheological (MR) fluid. Rapid fluid response gives
this equipment good response and control. In this chapter, we give basic isokinetic
exercise concepts using an MR fluid brake, focusing on high-speed controls up
to 900 deg/s at the elbow. We also suggest a new training mode we call iso-
contraction exercise.
11.1 INTRODUCTION
Clinicians use several types of muscle contraction, for example, isometric, isotonic
and isokinetic contraction, in quantitative evaluation of muscle strength. In the
isometric contraction, the angle of joints is fixed. A subject efforts to generate one's
muscle strength at one's best. In this type of muscle contraction, we can measure
maximal torque of muscles, but cannot measure dynamic properties. On the other
hand, in the isotonic contraction, muscle lifts a constant load and a muscle tension
is assumed to be constant. In this method, we can measure dynamic properties of
muscles, but cannot measure maximal torque. In order to measure both maximal
torque and dynamic properties of muscles, isokinetic contraction was suggested.
In this method, we can measure maximal torque at any angle of joint dynamically,
because subjects are required generating maximal torque during whole range of
