• Journal of KIISE:Computing Practices and Letters
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• v.12 no.6
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• pp.358-366
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• 2006

This paper describes a novel navigation algorithm using a locomotion interface with two 6-DOF programmable foot platforms. When a human walks on the locomotion interface (LI), the walking motions of the human are recognized by several sensors. Then, the sensed information is used by the LI for generation of infinite surfaces for continuous walking and the virtual environments for scene update according to motions of the human walking. The suggested novel navigation system can induce user's real walking and generate realistic visual feedback during navigation. A novel navigation algorithm is suggested to allow natural navigation in virtual environments by utilizing conditions of normal gait analysis. For realistic visual feedback, the virtual environment is designed with three components; 3D object modeler for buildings and terrains, scene manager and communication manager component. From experiments, the subjects were satisfied with the reality of the suggested navigation algorithm using the locomotion interface. Therefore, the suggested navigation system can allow a user to explore into various virtual terrains with real walking and realistic visual feedback.

• Journal of the Korean Society of Physical Medicine
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• v.13 no.1
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• pp.137-146
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• 2018

PURPOSE: This study examine the effect of community ambulation training on gait, depression and self - efficacy of stroke patients in order to develop more effective training methods of community rehabilitation. METHODS: In the experimental group, community ambulation training combined with indoor and outdoor walking was performed for 30 minutes three times a week for six weeks. In the control group, general indoor walking training was performed. The physical factors were assessed by a 10-meter walking test, six-minute walking test and community gait test. Psychological factors were assessed by the Korean version of the Epidemiology Center Depression Scale and Activity-Specific Balance Confidence Scale. RESULTS: In the 10-meter walking test, the normal walking speed was significantly improved after the intervention in both the experimental group and the control group (p<.05). However, the fast walking speed was significantly improved only in the experimental group (p <.05). ln the community gait test, the experimental group showed significant improvement (p<.05), but the control group did not. Depression and self-efficacy were significantly improved in the experimental group (p<.05) but not in the control group. CONCLUSION: Community ambulation training may improve the gait ability of stroke patients and reduce their depression and improve self-efficacy.

• Korean Journal of Applied Biomechanics
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• v.26 no.1
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• pp.135-142
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• 2016

Objective: The purpose of this study was to investigate the acute effect of walking on high heels on the behavior of fascicle length and activation of the lower limb muscles. Methods: Twelve healthy inexperienced high heel wearers (age: $23.1{\pm}2.0yr$, height: $162.4{\pm}4.9cm$, weight: $54.4{\pm}8.5kg$) participated in this study. They walked in high heels (7 cm) and barefoot on a treadmill at their preferred speed. During the gait analysis, the lower limb joint kinematics were obtained using a motion analysis system. In addition, the changes in fascicle length and the level of activation of the medial gastrocnemius (MG) were simultaneously monitored using a real-time ultrasound imaging technique and surface electromyography, respectively. Results: The results of this study show that the MG fascicle operates at a significantly shorter length in high heel walking ($37.64{\pm}8.59mm$ to $43.99{\pm}8.66mm$) in comparison with barefoot walking ($48.26{\pm}9.02mm$ to $53.99{\pm}8.54mm$) (p < .05). In addition, the MG fascicle underwent lengthening during high heel walking with relatively low muscle activation while it remained isometric during barefoot walking with relatively high muscle activation. Conclusion: Wearing high heels alters the operating range of the MG fascicle length and the pattern of muscle activation, suggesting that prolonged wearing of high heels might induce structural alterations of the MG that, in turn, hinder normal functioning of the MG muscle during walking.

• Korean Journal of Applied Biomechanics
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• v.29 no.2
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• pp.105-112
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• 2019

Objective: The main purpose of this study was to investigate the effects of wearing an ankle weight belt while performing gait in water by focusing on the effect of using ankle weights have on the gait kinematics and the muscle activities for developing optimum training strategies. Method: A total of 10 healthy male university students were recruited for the study. Each participant was instructed to perform 3 gait conditions; normal walking over ground, walking in water chest height, and walking in water chest height while using ankle weights. All walking conditions were set at control speed of $4km/h{\pm}0.05km/h$. The depth of the swimming pool was at 1.3 m, approximately chest height. The motion capture data was recorded using 6 digital cameras and the EMG was recorded using waterproof Mini Wave. From the motion capture data, the following variables were calculated for analysis; double and single support phase (s), swing phase (s), step length (%height), step rate (m/s), ankle, knee, and hip joint angles ($^{\circ}$). From the electromyography the %RVC of the lower limb muscles medial gastrocnemius, rectus femoris, erector spinae, semitendinosus, tibialis anterior, vastus lateralis oblique was calculated. Results: The results show significant differences between the gait time, and step length between the right and left leg. Additionally, the joint angular velocities and gait velocity were significantly affected by the water resistance. As expected, the use of the ankle weights increased all of the lower leg maximum muscle activities except for the lower back muscle. Conclusion: In conclusion, the ankle weights can be shown to stimulate more muscle activity during walking in chest height water and therefore, may be useful for rehabilitation purposes.

• Korean Journal of Exercise Nutrition
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• v.16 no.1
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• pp.11-17
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• 2012

The purposes of this study were to investigate the effects of acute exercise on blood vaspin, glucose level, and inflammatory cytokines in middle-aged women with pre-diabetes. Nineteen middle-aged women (normal women, n = 11) and women with pre-diabetes(n = 8), who were apparently healthy and not taking any medications affecting their blood pressure or blood glucose, participated. Body fatness parameters including body mass index, body fat percentage, and waist circumference were measured using a bio-impedance analyzer. Resting blood pressure was measured in duplicate, and mean values were used for the data analysis. Regardless of group assignments, all subjects participated in a 3-day consecutive walking exercise at an intensity of 65% VO_2max targeting an energy expenditure of 1200 kcal (400 kcal per day). The major outcome variables included total cholesterol, triglycerides, high-density lipoprotein cholesterol, glucose, vaspin, interleukin-6, and adiponectin levels. Unlike normal women, women with pre-diabetes had a significant improvement in the homeostatic model assessment of insulin resistance (p < 0.025) with no significant group difference in response to acute exercise. The findings suggest that acute exercise results in a significant improvement in insulin sensitivity without any change in serum vaspin levels in women with pre-diabetes.

• Journal of Institute of Control, Robotics and Systems
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• v.9 no.11
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• pp.943-951
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• 2003

A strategy for fault-tolerant gaits of autonomous legged robots is proposed. A legged robot is considered to be fault tolerant with respect to a given failure if it is guaranteed to be capable of walking maintaining its static stability after the occurrence of the failure. The failure concerned in this paper is a locked joint failure for which a joint in a leg cannot move and is locked in place. If a failed joint is locked, the workspace of the resulting leg is constrained, but legged robots have fault tolerance capability to continue static walking. An algorithm for generating fault-tolerant gaits is described and, especially, periodic gaits are presented for forward walking of a hexapod robot with a locked joint failure. The leg sequence and the formula of the stride length are analytically driven based on gait study and robot kinematics. The transition procedure from a normal gait to the proposed fault-tolerant gait is shown to demonstrate the applicability of the proposed scheme.

• Nutritional Sciences
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• v.4 no.1
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• pp.34-38
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• 2001

The purpose of this study was to compare the energy expenditure of normal-weight and overweight Korean middle-aged women (40-60 yr). Middle-aged oveweight ($BMI\;{\geq}\;25$, n= 20) and normal-weight women were ($BMI\;{\leq}\;23$, n = 20) were recruited in Seoul. Anthropometric measurements, body composition, energy intake, daily activity time, and energy costs of some daily activities were measured. Energy expenditure at rest and while reading the newspaper, washing dishes, mopping the floor, and walking on a treadmill at 1.0, 2.0, 3.5mph were measured by indirect calorimeter and total daily energy expenditure was estimated by summation of energy costs of different activities. The overweight group had significantly higher values of body weight, triceps skinfold thickness, thigh circumference, waist circumference, hip circumference, BMI, WTR, WHR, body surface area, percentage body fat, fat mass, fat free mass (FFM), and muscle mass compared to normal-weight group. The energy intakes of both groups were close to RDA and other nutrient intake status was also satisfactory. There were no significant differences in intakes of energy and nutrients between the two groups. Overweight subjects showed lower energy expenditure per kg body weight for reading the newspaper, washing dishes and mopping the floor, and walking on a treadmill at 2.0 and 3.5 mph, however, energy expenditure per kg FFM did not differ between the two groups. Daily energy expenditure for all activities was significantly higher in the overweight compared to the normal-weight group due to higher body weight. Both overweight and normal-weight groups showed negative energy balance between energy intake and energy expenditure, and there was no significant difference in energy balance between the two roups. Total daily energy expenditure correlated highly with FFM and body surface area. The result of present study does not offer an explanation on the energy imbalance and weight gain of overweight women.

• The Journal of the Korea institute of electronic communication sciences
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• v.11 no.2
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• pp.215-222
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• 2016

Research on gait recognition and its use is actively underway. This study suggests a method to recognize abnormal gaits of pedestrians. The purposes of the existing research to recognize normal steps are to measure physical activities and to validate people by their walks, but the purpose to recognize abnormal steps in this study is to insure the safe life of pedestrians. There are situations in which pedestrians are unaware of themselves vulnerable and can not ask for help. The purpose of this research is that even if pedestrians are unaware of themselves and there are no spontaneous requests for helps, it is intended for them to escape from dangers and difficulties by adopting the recent IOT technology. Hence, this study analyzes normal pace of pedestrians using the triaxial acceleration sensors, and takes ranges of their normal walking. And then, the steps of pedestrians are measured using the triaxial acceleration sensors, contrasted with their normal walking ranges, and determine whether their steps are normal or not. When it is out of the state for normal paces, a method to determine as abnormal paces is suggested.

• Korean Journal of Applied Biomechanics
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• v.16 no.4
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• pp.73-81
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• 2006

The purpose of this study was to investigate the effects of strength training on knee joint torque during walking in an adolescent with trisomy-21 Down syndrome. One adolescent with Down syndrome and one normal child participated in this study. Strength training consisted of eight exercises: squat, hamstring curl, hip adduction, hip abduction, knee extension, toe raise, sit-ups, and hyperextension of the waist. The participant with Down syndrome was participated in strength training for 12 weeks, three times a week, three sets, 10-15 RM; resistance was adjusted according to the principle of progressive overload. To measure the effect of strength training, isokinetic strength variables and knee joint torques were measured before training and after 12 weeks of training. The participant with Down syndrome had some abnormalities in controlling knee motion during walking due to muscle hypotonia, ligament laxity, and weakness of muscles. Post-training isokinetic strength increased compared to pre-training measurements. Knee range of motion were increased after strength training. Strength training did not affect ad/adduction and in/exteranl moments but did have an effect on flexor/extensor moment and timing.

• Journal of Institute of Control, Robotics and Systems
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• v.14 no.7
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• pp.672-678
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• 2008

This paper proposes a new rehabilitation robot with upper and lower limb connections for gait training. As humans change a walking speed, their nervous systems adapt muscle activation patterns to modify arm swing for the appropriate frequency. By analyzing this property, we can find a relation between arm swinging and lower limb motions. Thus, the lower limb motion can be controlled by the arm swing for walking speed adaptation according to a patent's intension. This paper deals with the design aspects of the suggested gait rehabilitation robot, including a trajectory planning and a control strategy. The suggested robot is mainly composed of upper limb and lower limb devices, a body support system. The lower limb device consists of a slider device and two 2-dof footpads to allow walking training at uneven and various terrains. The upper limb device consists of an arm swing handle and switches to use as a user input device for walking. The body support system will partially support a patient's weight to allow the upper limb motions. Finally, we showed simulation results for the designed trajectory and controller using a dynamic simulation tool.