Optimum conductive fabric sensor sites for evaluating the status of knee joint movements using bio-impedance

The upper side of subjects' lower limbs was divided into two areas and the lower side of subjects' lower limbs was divided into three areas. The spots were matched and 6 pairs were selected. Subjects were composed of 15 males (age: 30.7 ± 5.3, weight: 69.8 ± 4.2 kg, and height: 173.5 ± 2.8 cm) with no known problems with their knee joints. Bio-impedance changes according to knee joint flexion/extension assessments were calculated and compared with bio-impedance changes by an ankle joint flexion/extension test (SNR I) and a hip joint flexion/extension test (SNR II).The bio-impedance changes of the knee joint flexion/extension assessment were 35.4 ± 20.0 Ω on the (1, 5) pair. SNR I was 3.8 ± 8.4 and SNR II was 6.6 ± 7.9 on the (1, 5) pair.The optimum conductive fabric sensor configuration for evaluating knee joint movements were represented by the (1, 5) pair.As the number of people who have problems with their joints increases, the need for joint rehabilitation cures has gradually risen. The past status and future status of joint rehabilitation are always estimated in the curing phase of joint rehabilitation. In particular, the status of knee joint movement as regards rehabilitation is evaluated using goniometers to measure knee joint angles, active and passive marker systems to detect motion, and electromyography (EMG) to measure muscle fatigue around knee joints [1].There have been many studies that utilize the bio-impedance measurement method to analyze the movements of the upper and lower limbs [2] and [3]. A fixed electrical current flows into the limbs through four standard disposable electrodes in this method. The current flows in the muscles and blood vessels, which have relatively low resistivity levels in the human body. This method is used to measure bio-impedance changes following volume changes of muscles and blood vessels around a knee joint. The result of the bio-impedance changes is used to evaluate the movements [4] and [5]. However, the method using