• Journal of Mechanical Science and Technology
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• v.17 no.6
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• pp.825-835
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• 2003

Previous studies have demonstrated the importance of joint angle errors mainly due to skin artifact and measurement errors during gait analysis. Joint angle errors lead to unreliable kinematics and kinetic analyses in the investigation of human motion. The purpose of this paper is to present the Joint Averaging Coordinate System (JACS) method for human gait analysis. The JACS method is based on the concept of statistical data reduction of anatomically referenced marker data. Since markers are not attached to rigid bodies, different marker combinations lead to slightly different predictions of joint angles. These different combinations can be averaged in order to provide a "best" estimate of joint angle. Results of a gait analysis are presented using clinically meaningful terminology to provide better communication with clinical personal. In order to verify the developed JACS method, a simple three-dimensional knee joint contact model was developed, employing an absolute coordinate system without using any kinematics constraint in which thigh and shank segments can be derived independently. In the experimental data recovery, the separation and penetration distance of the knee joint is supposed to be zero during one gait cycle if there are no errors in the experimental data. Using the JACS method, the separation and penetration error was reduced compared to well-developed existing methods such as ACRS and Spoor & Veldpaus method. The separation and penetration distance ranged up to 15 mm and 12 mm using the Spoor & Veldpaus and ACRS method, respectively, compared to 9 mm using JACS method. Statistical methods like the JACS can be applied in conjunction with existing techniques that reduce systematic errors in marker location, leading to an improved assessment of human gait.

• Journal of Korean Academy of Nursing
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• v.36 no.1
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• pp.189-196
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• 2006

Purpose: The purpose of this research was to test the effects of ST35 & Sulan moxibustion on knee joint pain, range of motion, and discomfort during Activies of Daily Living (ADL) in elderly with knee joint pain. Method: A nonequivalent control group pre-post test research design was used. Thirty four elderly who had knee joint pain were studied. Of them, sixteen were in the experimental group and eighteen the control group. The instruments used for this study were NRS, goniometer, and a modified ADL questionnaire developed by Lee. Result: The pain scores of right & left knee joint after moxibustion were significantly different between the experimental group and the control group (Right: F=26.27, p=0.000, Left: F=20.77, p=0.000). Right and left knee ROM scores were significantly different between the experimental group and the control group after moxibustion (Right: F=10.74, p=0.003, Left: F=9.239, p=0.005). Discomfort during ADL scores were significantly different between the experimental group and the control group after moxibustion (F= 32.31, p=0.000). Conclusion: It is necessary that nurses provide the elderly with knee joint pain with moxibustion to reduce joint pain and to increase knee ROM as an alternative therapy.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.37 no.12
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• pp.1121-1127
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• 2013

This study deals with experimental studies on electromyogram (EMG) measurements and functional electrical stimulation (FES) for the rehabilitation of a shoulder-joint. Based on the structure, motion, and main functions of the musculoskeletal system in a shoulder-joint, the muscles playing a major role for the motion in the sagittal plane were selected for the experiment. First, the surface electromyogram of the main muscles was measured according to the joint angle. The results showed that the change in the surface EMG was linearly proportional to the change in the joint angle. Second, the joint angle was measured during FES at shoulder muscles. The results showed that the joint angle increased as the FES current increased in a certain range of FES. It was confirmed that the willingness of muscles to move could be detected by measuring EMG and that the generation of muscle tension could be assisted by FES for active rehabilitation.

• Korean Journal of Applied Biomechanics
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• v.22 no.3
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• pp.357-363
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• 2012

The purpose of this study was to investigate the effects of different saddle heights on lower-limb joint angle and muscle activity. Six elite cyclists(age: $32.2{\pm}5.2years$, height: $171.0{\pm}3.5cm$, weight: $79.7{\pm}5.6kg$, cycle career: $13{\pm}6.2years$) participated in three min. submaximal(90 rpm) pedaling tests with the same load and cadence based on saddle heights where subject's saddle height was determined by his knee flexion angle when the pedal crank was at the 6 o'clock position. Joint angles(hip, knee, ankle joints) and the activity of lower limb muscles(biceps femoris(BF), vastus lateralis(VL), tibialis anterior(TA) and gastrocnemius medial(GM)) were compared by measuring 3D motion and electromyography(EMG) data. Results showed that there were significant differences in minimum hip & knee joint angle and range of motion of hip and knee joint between saddle heights. Onset timing and integrated EMG of only BF among 4 muscles were significantly different between saddle heights. Especially there was a negative relationship between minimum hip joint angle and onset timing of BF in most subject, which means that onset timing of BF became fast as the degree of bending of the hip joint became larger by saddle height. Optimal pedaling will be possible through increased amount of muscle activation due to the appropriate burst onset timing by proper pedaling posture with adjusted saddle height.

• Physical Therapy Korea
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• v.21 no.2
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• pp.8-17
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• 2014

The purpose of this study was to examine the effects of hip joint mobilization (HJM) on walking ability, balance ability, and the joint range of motion in stroke patients to minimize the problems of the musculoskeletal system in patients with central nervous system diseases. All volunteers were randomly assigned to the HJM group ($n_1=14$) and the general neurodevelopment therapy (NDT) group ($n_2=16$). The HJM procedure involved applying Maitland mobilization techniques (distraction, lateral gliding, inferior gliding, and anterior gliding) by grade 3 to both hip joint. The mobilization process included mobilization and NDT for 15 min/day, 3 days a week for 4 weeks. The outcome measures were evaluated, including the hip joint passive range of motion (ROM) test and femur head anterior glide test (FHAG) using prone figure four test, dynamic and static balance abilities [timed up and go (TUG) test and center of pressure (COP) analysis], and walking ability [10-meter walking test (10MWT) and 6-min walking test (6MWT)]. Both the groups showed significant post-training differences in the hip joint ROM (FHAG and degree of hip extension) and 10MWT. The post-training improvements in the TUG test were significantly greater in patients of the HJM group than in the NDT group; however, there were no post-training improvements in COP in both groups. Patients in the HJM group showed post-training improvement in the 6MWT; however, statistically significant differences were not observed. Patients in the NDT group showed post-training improvements in the 6MWT. These results suggest that HJM improves hip joint ROM, dynamic balance ability, and walking speed in stroke patients. However, further studies are required to evaluate the long-term therapeutic efficacy of HJM in stroke patients.

• The Journal of Korean Academy of Orthopedic Manual Physical Therapy
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• v.27 no.2
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• pp.77-85
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• 2021

BACKGROUND: This study aimed to determine the changes in muscle strength and walking ability in patients who complained of knee instability due to excessive pronation of the foot. METHODS: Twenty patients (ten men and ten women) who complained of instability of the knee joint due to excessive pronation of the foot participated in the experiment. In the experimental group, the internal rotation of the tibia caused by excessive adduction of the foot was maintained as external rotation, and the joint state was to recognize the movement of the joint position changed through maintenance of the muscle. This exercise was performed five times for each patient, and the muscle strength maintenance was performed for 20 seconds. In the control group, stretching and range of motion (ROM) exercises were performed. For the stretching exercise, one specific motion was performed for 20 second, and the ROM exercise was performed to confirm the change in muscle strength in the knee joint area and walking ability. RESULTS: The knee flexion and extension strength in the patients with excessive pronation of the foot differed significantly from those in the subjects from the control group (p<.05). Further, the before-after comparison of the step time and length in the evaluation of walking ability, which affects overall postural movement due to knee joint instability, revealed a significant difference between the experimental and control groups (p<.05). CONCLUSION: The patients that were subjected to manual therapy and ROM exercise for the knee joint showed improved knee joint muscle strength and walking ability compared to the subjects from the control group.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2004.10a
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• pp.1160-1165
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• 2004

The purpose of this study was to calculate three dimensional angular displacements, moments and joint reaction forces of the ankle joint during the waist pulling, and to assess the ankle joint reaction forces according to different perturbation modes and different levels of perturbation magnitude. Ankle joint model was assumed 3-D ball and socket joint which is capable of three rotational movements. We used 6 cameras, force plate and waist pulling system. Two different waist pulling systems were adopted for forward sway with three magnitudes each. From motion data and ground reaction forces, we could calculate 3-D angular displacements, moments and joint reaction forces during the recovery of postural balance control. From the experiment using falling mass perturbation, joint moments were larger than those from the experiment using air cylinder pulling system with milder perturbation. However, JRF were similar nevertheless the difference in joint moment. From this finding, we could conjecture that the human body employs different strategies to protect joints by decreasing joint reaction forces, like using the joint movement of flexion or extension or compensating joint reaction force with surrounding soft tissues. Therefore, biomechanical analysis of human ankle joint presented in this study is considered useful for understanding balance control and ankle injury mechanism.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2012.05a
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• pp.1151-1152
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• 2012

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2013.05a
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• pp.1419-1420
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• 2013

• Korean Journal of Applied Biomechanics
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• v.19 no.4
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• pp.627-636
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• 2009

This study aims to provide a scientific basis for the abstract beauty of dance by analyzing the effects of controlling the breath during the walking motion of Korean dance. The objective of the study is to determine the significance of breathing during Korean dance, as it is externally expressed and technologically segmented, let alone the internal beauty of Korean dance. The results of this study show that the position of the body center and ASIS during the walking motion that uses breath was lower than that of the walking motion that does not use the breath. In addition, in each replacement of the knee joint and ankle joint, a narrow angle, in which bending is used a lot, appeared during the walking motion that uses the breath, but not during the walking gesture that does not use the breath. This occurred during the bending motion. In the first peak point, the vertical ground reaction force during the walking motion that uses the breath was higher than that during the walking motion that does not use the breath.