• Korean Journal of Applied Biomechanics
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• v.31 no.1
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• pp.30-36
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• 2021

Objective: The objective of the present study was to analyze the relationship between strength of the lower extremity's joints and their local dynamic stability (LDS) of gait in elderly women. Method: Forty-five elderly women participated in this study. Average age, height, mass, and preference walking speed were 73.5±3.7 years, 153.8±4.8 cm, 56.7±6.4 kg, and 1.2±0.1 m/s, respectively. They were tested torque peak of the knee and ankle joints with a Human Norm and while they were walking on a treadmill at their preference speed for a long while, kinematic data were obtained using six 3-D motion capture cameras. LDS of the lower extremity's joints were calculated in maximum Lyapunov Exponent (LyE). Correlation coefficients between torque of the joints and LyE were obtained using Spearman rank. Level of significance was set at p<.05. Results: Knee flexion torque and its LDS was negatively associated with adduction-abduction and flexion-extension movement (p<.05). In addition, ratio of the knee flexion torque to extension and LDS was negatively related to internal-external rotation. Conclusion: In conclusion, knee flexion strength should preferentially be strengthened to increase LDS of the lower extremity's joints for preventing from small perturbations during walking in elderly women.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2006.05a
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• pp.169-170
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• 2006

The purpose of this study was to evaluate the smoothness of the gait pattern according to shoe, walking speed, and slope. Eleven male university students used three types(running shoes, mounting climbing boots, elevated forefoot walking shoes) of shoes at various walking speeds(1.19, 1.25, 1.33, 1.56, 1.78, 1.9, 2.0, 2.11, 2.33m/s) and gradients (0, 3, 6, 10%) on a treadmill. Three-dimensional motion analysis (Motion Analysis Corp, Santa Rosa, CA, USA) was conducted with 4 Falcon high speed cameras. The results showed that elevated forefoot walking shoes had the lowest value of normalized jerk at the heel, which means that elevated forefoot walking shoes had the smoothest walking pattern at the heel. In contrast, elevated forefoot walking shoes had greater normalized jerk at the center of mass (COM) at most walking speeds, which means that the smoothness of gait pattern at the center of mass is the lowest for the elevated forefoot walking shoes. This movement at the COM might even have a beneficial effect of activating muscles in the back and abdomen more than other shoes.

• PNF and Movement
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• v.9 no.2
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• pp.29-37
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• 2011

Purpose : The purpose of this study was to find out of an effect of forward, backward walking using partial weight bearing on walking of the patient with incomplete spinal cord injury. Methods : The average age, and the term of being sick of 6 patients who were selected as the subjects with incomplete spinal cord injury and who received medical attention in the National Rehabilitation Hospital, was 50.3 years old, and 10.7 months, and those were also the patients that were classified as ASIA-C or D by ASIA. The forward, backward walking using a partial weight bearing system as the research method, took total 6 weeks, 3 days per week, 3 times per day, total 45 minutes for each time(15 minutes for a time, 5 minutes for a breathing time), and the 15 minutes was used for forward walking 7.30 minutes, backward walking for 7.30 minutes, to find out before and after the test of WISCI, PCI, Walking Speed, Motor Score of Lower Limbs for the selected patients with incomplete spinal cord injury. Results : The result was showed WISCI from 17 points to 17 points that is, no change occurred at all, and PCI from $161.01{\pm}103.06$ to $74.97{\pm}58.19$, some amount of reduction that is not statistically significant(p<.05). Regarding walking speed, it increased from $24{\pm}.07m/sec$ to. $61{\pm}.35m/sec$, that is statistically significant(p<.05), and motor score of lower limbs showed statistically significant increase like from $33.17{\pm}7.08$ to $37{\pm}5.14$(P<.05). Conclusion : The 4 evaluation categories seem to have shown differences due to an insufficient number of subjects, and short test term, and it seems the more diverse task-oriented walking exercises should be studied in the coming days.

• Journal of The Korean Society of Integrative Medicine
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• v.9 no.3
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• pp.135-144
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• 2021

Purpose : The purpose of this study was to investigate the effect of 2 weeks of backward walking exercise (BWE) on cervical angle and gait parameters in college students with forward head posture. Methods : Fifteen subjects participated in the experiment. All the participants had a craniovertebral angle (CVA) of 55 degrees or less. The purpose of the study was explained to all the subjects prior to participation, and volunteered to take part in the study. A camera capable of taking pictures of the lateral plane was installed at a distance of 1.5 meters from each subject. Images of forward head posture were obtained before and after performing the BWE, and the CVA and craniorotational angle (CRA) were compared pre- versus post exercise. Foot pressure and gait parameters (step length of left and right, stride length, stance of left and right, swing of left and right, step time of left and right, and stride time) were measured using a rehabilitation treadmill. The subjects performed the BWE for 2 weeks. The exercise program consisted of a 5-minute warm-up exercise, 20-minute main exercise, and 5-minute cool-down exercise. In the main exercise, the treadmill speed was set to 2.4 km/h in the first week and 3.4 km/h in the second week. A paired t test was used to compare the CVA and CRA and gait parameters before and after the exercise. Results : Comparison of the CVA and CRA before and after the BWE revealed a significant difference post exercise, with a marked improvement in forward head posture after the exercise (p<.05). Conclusion : Based on the results of this study, the BWE is considered to be an effective exercise for the forward head posture. Also, additional research is needed to shed light on the impact of the BWE on gait parameters.

• Korean Journal of Applied Biomechanics
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• v.31 no.3
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• pp.176-182
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• 2021

Objective: The purpose of this study is to investigate whether the athletic knee show greater rotation and translation movement than non-athletic knee during the treadmill walking with their preferred speed in a complete gait cycle. Method: Thirty young and healthy male subjects participated in the study, fifteen handball players (mean age: 19.6 ± 1.4 years old, mean weight: 85 ± 11.9 Kg, mean height: 179.8 ± 4.7) and fifteen non-athletes (mean age: 22.8 ± 1.2 years old, mean weight: 74.5 ± 8.6 Kg, mean height: 175 ± 5.9). Three-dimensional positional coordinate of lower limb during treadmill walking were analyzed. Results: There were significant differences (t (22.014)=1.585, p=0.127 in the range of internal and external rotation with mean value for handball player (M=14.4513, SD=2.3839) was higher than non-athletes (M=13.3327, SD=1.337). The magnitude of the difference in the means (mean difference=1.11867, 95% CI: -0.34489 to 2.5822) was significant. There were also significant differences (t (17.956)=1.654, p=0.116 in the max abduction and adduction with mean value for handball player (M=5.7160, SD=2.49281) was higher than non-athletes (M=4.5773, SD=0.94667). The magnitude of the difference in the means (mean difference=1.138, 95% CI: -0.30805 to 2.58539) was significant. At significance level 0.05. Conclusion: Finding of this study suggest that to understand the actual characteristic of knee motion studies have to be done in different walking and running trial at variable speed.

• PNF and Movement
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• v.16 no.2
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• pp.179-185
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• 2018

Purpose: This study aimed to analyze the visual and spatial elements of the gait of a stroke patient who had diverse ankle weight loads applied, according to weight changes. Methods: The subject was a 57-year-old stroke patient diagnosed and hospitalized with a left intracerebral hemorrhage. A weight equivalent to 0%, 1%, and 2% of his body weight was applied to the area 5cm upward from the ankle using a Velcro strap. He was then trained on a treadmill, receiving a six-minute walk test to evaluate his gait ability. A gait analyzer was used to collect visual and spatial elements, such as gait distance, gait velocity, cadence, step length, stride length, and swing phase, according to a weight load equivalent to 0%, 1%, and 2% of his body weight. Results: According to the results of applying 0%, 1%, and 2% of his body weight on the ankle, except for gait velocity, his gait distance, cadence, step length, stride length, and swing phase were higher when 1% of his body weight was applied compared to 0% or 2% of his body weight. Conclusion: Applying a weight equivalent to 1% of the body weight to the ankle positively affected the visual and spatial element of the gait and heightened the efficiency of exercise during treadmill training, a gait-training tool generally used for stroke patients. However, the result is difficult to generalize because the number of subjects was small with only one subject.

• Journal of Biomedical Engineering Research
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• v.40 no.6
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• pp.235-241
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• 2019

The purpose of this study was to investigate the effect of the body temperature peripheral circulation with vibration shoes in healthy 10 adults. The magnetic vibration device with non-electric power was mounted in the midsole of the vibration shoes. The experiment was divided into two groups: vibration shoes and no vibration shoes. Subjects were randomly selected and measured body surface temperature by digital infrared thermal imaging (DITI) and non-invasive capillaries change by nailfold microscope (NFM). After walking in a treadmill for 15 minutes at 4.0 km/h speed wearing normal shoes or vibration shoes, DITI and NFM were measured. The walking with vibration shoes showed the body surface temperature shift from the proximal to the distal. In addition, the diameter of the nailfold capillary in the vibration shoes group was thicker and clearer due to the increased blood flow than that of the no vibration shoes group. The vibration shoes are easy to apply to anyone who can walk because it can give vibration stimulation by walking without additional time, cost, and effort in daily life. Further studies are needed to explain the physiological effects of vibration frequency and intensity on the long-term perspective of target subjects resulting from vascular dysfunction.

• PNF and Movement
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• v.18 no.1
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• pp.55-64
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• 2020

Purpose: The purpose of this study was to compare the strength and walking ability of chronic stroke patients following either proprioceptive neuromuscular facilitation (PNF) pattern training with pressure biofeedback units (feedback group) or PNF pattern training without pressure biofeedback units (control group). Methods: Eighteen participants with chronic stroke were recruited from a rehabilitation hospital. They were divided into two groups: a feedback group (n = 8) and a control group (n = 10). They all received 30 minutes of neurodevelopmental therapy and PNF training for 15 minutes five times a week for three weeks. Muscle strength and spatiotemporal gait parameters were measured. Muscle strength was measured by hand-held dynamometer; gait parameters were measured by the Biodex Gait trainer treadmill system. Results: After the training periods, the feedback group showed a significant improvement in hip abductor muscle strength, hip extensor muscle strength, step length of the unaffected limb, and step time of the affected limb (p<0.05). Conclusion: The results of this study showed that proprioceptive neuromuscular facilitation pattern training with pressure biofeedback units was more effective in improving hip muscle strength and walking ability than the proprioceptive neuromuscular facilitation pattern training without pressure biofeedback units. Therefore, to strengthen hip muscles and improve the walking ability of stroke patients, using pressure biofeedback units to improve trunk stability should be considered.

• Journal of Biomedical Engineering Research
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• v.27 no.6
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• pp.323-331
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• 2006

The purpose of this study was to investigate the effect of performing a cognitive task during treadmill walking on the stride rate variability. Ten university students(age $24.0{\pm}0.25$, height $172{\pm}3.1cm$, weight $66{\pm}5.3kg$) were participated in dual task experiments which consist of both walking alone and walking with a cognitive task. Two-back task was selected for the cognitive task since it did not have learning effect during the experimental procedure.3D motion analysis system was used to measure subject's position data by changing walking speed with 4.8, 5.6, 6.4, 6.8, and 7.2 km/hr. Stride rate was calculated by the time between heel contact and heel contact. Accuracy rate of a cognitive task during walking, coefficient of variance, allometric scaling methods and Fano factor were used to estimated the stride rate variability. As the walking speed increased, accuracy rate decreased and the logarithmic value of Fano factor increased which showed the statistical difference. Thus it can be concluded that the gait control mechanism is distracted by the secondary attention focus which is the cognitive task ie. two-back task. Further study is needed to clarify this by increasing the number of subject and experiment time.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.12
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• pp.363-370
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• 2016

The purpose of this study was to determine the effects of speed variations in treadmill training on the thickness of lower extremity muscles. A total of 36 university students were divided into three groups: MVTG (n=12), HVTG (n=12), and ATG (n=12). Subjects in MVTG underwent treadmill training with their own average speed; those in HVTG underwent treadmill training with 130% speed of their own average speed; and those in ATG underwent treadmill training with alteration of speed, between 100% and 130% of their own average speed. Treadmill training was performed for 60 minutes a day, three times per week, for a total of 6 weeks. Ultrasonography was used to compare the muscle thickness between rectus femoris, vastus lateralis, gastrocnemius, and tibialis anterior. The result was as follows: The rectus femoris, vastus lateralis, and gastrocnemius were significantly increased after the training period, and they also were statistically significant in interaction. Moreover, tibialis anterior was also significantly increased. Therefore, compared to the average-speed treadmill training, speed variations had a greater effect on thickening the lower extremity muscles. In the near future, we will conduct a study applying the findings from this study in a rehabilitation program for patients with gait disturbance due to nervous or musculoskeletal system disease.