• Proceedings of the KIEE Conference
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• 2006.10c
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• pp.530-532
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• 2006

In this paper, we propose stable walking algorithm using ZMP for the biped robot in the slope-way. At first, we define discrete state variables that classified stable area and unstable area by center of mass from ZMP during slope-way walking. For the stable walking gait, the discrete state controller for determining the high-level and low-level decision making are designed. The high-level decision making is composed of the discrete state variables; left foot support phase, right foot support phase, flat-way, and slope-way. Then the continuous state controller is implemented for the low-level decision making using ZMP.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.65 no.4
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• pp.673-677
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• 2016

In this study, In order to measure foot pressure, it makes analyzing device using multi-pressure sensor. This device was limited frequency band to 5Hz by using low-pass filter and MCU was detected signal every milliseconds. After wearing the device, the result was confirmed by blue-tooth to measure wirelessly. Also, we propose an algorithm to obtain the walking pattern using a time table in each of the detected peak from the pressure sensor. Using the algorithm, right walking pattern and abnormal pattern was detected. The results can be reflected more individual walking patterns than when using a conventional methods and also, developed device was no restriction on the human activity.

• 한국HCI학회:학술대회논문집
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• 2008.02a
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• pp.534-539
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• 2008

This paper is about intelligent hexapod robot for the support walking of the aged person. The robot using various sensors and small camera has various abilities of forward backward walking, turing left or right, control the speed of walking, avoiding the obstacles and detecting risky situation of fire or gas. To let the aged feel soft and safe walking, we used special servo motor and developed hexapod walking mechanism and effective algorithm.

• The Journal of Korean Physical Therapy
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• v.25 no.2
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• pp.88-95
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• 2013

Purpose: The purpose of this study was to conduct an analysis of kinematics of lower extremities and trunk in stance phase of walking according to turning direction. Methods: Ten university students (five male, five female) who were in their 20s (mean age was 20.6 years old) participated in this study. Participants did not have participants did not have any problem with skeletal muscular system. We used the "Qualisys motion capture system" for analysis of trunk and lower extremity movement in stance phase of walking according to turning direction. We collected data while subjects walked a distance of 10 m, and at the 6 m line, subjects were required to turn to the left side and the right leg was positioned in stance phase and the left leg was positioned in swing. For data analysis, the SPSS for Windows ver. 20.0 statistics program was used in performance of one way analysis of variance according to turning direction. Results: Significant difference of trunk and lower extremities was observed for turning direction according to walking cycle (p<0.05). Upper trunk movement showed a greater increase at three dimensions than lower trunk, and in heel off phase, pelvic movement showed a greater increase than lower trunk (p<0.05). In 45 degree and 90 degrees of turning direction, all movements of trunk and lower extremities were significantly different among three events of stance phase (p<0.05). Conclusion: We suggest that three-dimensional movement analysis of trunk and lower extremities during turning movement was very important in order to indicate increasing balance or walking ability for people with impaired movement or walking.

• Journal of the Korean Society of Physical Medicine
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• v.13 no.1
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• pp.89-98
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• 2018

PURPOSE: While underwater, patients with hemiplegia experience unwanted limb flotation on their paretic side due to low muscle mass and high body fat. However, only a limited number of studies support the effectiveness of this practice. Therefore, the purpose of this study was to determine how the balance and walking abilities of patients with hemiplegia due to stroke were affected by wearing an aquatic cuff on their ankles during underwater treadmill walking. METHODS: Twenty stroke patients were divided into an experimental group comprised of 20 patients who would wear an aquatic cuff and a control group comprised of 10 patients without an aquatic cuff. Both groups underwent a six-week intervention for 30 minutes a day three times a week. To evaluate the groups' balance and walking abilities before and after the intervention, the 10 m walking test, timed up go test, Berg Balance Scale, functional reaching test, and the GAITRite system were used. RESULTS: The results of the 10 m walking test, timed up go test, differences between the left and right gait cycles, and functional reaching test showed statistically significant differences in the rates of change between the two groups (p<.05). CONCLUSION: The study results suggest that underwater treadmill training in stroke patients can be more effective when they wear an aquatic cuff on their ankles compared to wearing no aquatic cuff.

• Korean Journal of Applied Biomechanics
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• v.27 no.1
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• pp.35-43
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• 2017

Objective: The purpose of this study was to determine how gaze angle affects muscle activity and kinematic variables during treadmill walking and to offer scientific information for effective and safe treadmill training environment. Method: Ten male subjects who have no musculoskeletal disorder were recruited. Eight pairs of surface electrodes were attached to the right side of the body to monitor the upper trapezius (UT), rectus abdominis (RA), erector spinae (ES), rectus femoris (RF), bicep femoris (BF), tibialis anterior (TA), medialis gastrocnemius (MG), and lateral gastrocnemius (LG). Two digital camcorders were used to obtain 3-D kinematics of the lower extremity. Each subject walked on a treadmill with a TV monitor at three different heights (eye level; EL, 20% above eye level; AE, 20% below eye level; BE) at speed of 5.0 km/h. For each trial being analyzed, five critical instants and four phases were identified from the video recording. For each dependent variable, one-way ANOVA with repeated measures was used to determine whether there were significant differences among three different conditions (p<.05). When a significant difference was found, post hoc analyses were performed using the contrast procedure. Results: This study found that average and peak IEMG values for EL were generally smaller than the corresponding values for AE and BE but the differences were not statically significant. There were also no significant changes in kinematic variables among three different gaze angles. Conclusion: Based on the results of this study, gaze angle does not affect muscle activity and kinematic variables during treadmill walking. However, it is interesting to note that walking with BE may increase the muscle activity of the trapezius and the lower extremity. Moreover, it may hinder proper dorsiflexion during landing phase. Thus, it seems to reasonable to suggest that inappropriate gaze angle should be avoided in treadmill walking. It is obvious that increased walking speed may cause a significant changes in biomechanical parameters used in this study. It is recommended that future studies be conducted which are similar to the present investigation but using different walking speed.

• PNF and Movement
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• v.16 no.1
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• pp.7-17
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• 2018

Purpose: The aim of this study was to investigate the effects of coordinative locomotor training in a chronic stroke patient. Methods: A left hemiplegic patient diagnosed with a right middle cerebral artery stroke participated in this research. The patient's functional conditions were assessed, and a coordinative locomotor training program was initiated to resolve the problems identified. A set of movements deemed difficult based on the brief International Classification of Functioning, Disability and Health core set for stroke and d4501 (long-distance walking) were agreed as improvement targets. The program comprised warm up, main, cool-down, and home exercises. Repeated measurements were obtained, as follows: five times at baseline (A), 10 times during the intervention (B), and five times after the intervention (A). The study period was 7 weeks, and the intervention period was 1 h per day, twice a week for 5 weeks. Various tools, including the community walking test (CWT), 10-m walking test (10 MWT), 6-min walking test (6 MWT), and timed up and go (TUG) test, were conducted to assess the patient's walking ability. Changes in functional domains before and after the ICF Qualifier were compared. The mean values of the descriptive statistics were calculated, and a visual analysis using graphs was used to compare the rates of change. Results: The results showed that the CWT, 10 MWT, 6 MWT, and TUG test scores during the intervention period improved and that this improvement remained, even during the baseline period. In addition, the ICF Qualifier before and after the comparison decreased from moderate to mild. Conclusion: Based on the results, we propose that coordinative locomotor training can have positive effects on community ambulation of chronic stroke patients.

• 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.

• Journal of Korean Physical Therapy Science
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• v.25 no.2
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• pp.7-14
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• 2018

Purpose: This study was conducted to analyze the effect of bag type on gait kinematic factors. The purpose of this study was to compare the Cobb's angle, leg angle and foot pressure difference according to bag type among 20 university students. Methods: The bag type was applied with two kinds of bags: not wearing a bag, backpack, and an eco bag. The bag weight was 10% of subjects weight in during experiment and only bag weight was 0.5kg. Results: Knee joint angle is increased when wearing backpack or an eco bag than not wearing bag. Cobb's angle increased when wearing backpack and wearing eco back. The difference in right and left foot pressure increased when wearing eco bag than not wearing bag and wearing backpack. Conclusion: Therefore, wearing a heavy backpack or an eco bag when walking for a long time may cause scoliosis and change the walking form.

• Journal of the Ergonomics Society of Korea
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• v.28 no.3
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• pp.33-39
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• 2009

Impact force to a body during walking depends on walking speed, walking steps, the condition of the floors and shoes, and weight. The ground reaction force and the foot pressure can be measured instantaneous force easily, but it's difficult to find out the amount of transferring forces to the body. On the other hand, the acceleration has an advantage for analyzing the amount of transferring forces. However, most of studies about impact forces to the ground reaction during exercise have been limited to analyze instantaneous forces. The important thing is to evaluate characters and the amount of the impact force rather than the magnitude. Therefore, this study analyze the impact force using 3 axis acceleration in three dimensions (x; anterior-posterior, y; left-right and z; longitudinal axis) using three axis acceleration. As working speed increased, impact forces increased significantly. Impact forces on x axis and z axis are higher at lower limb than that of upper limb. However, impact force at the knee is higher than that of other parts on y axis regardless of walking speed significantly. In addition, relations of the impact forces as interaction of experiment factors as well as effect of each factor are analyzed.