• ETRI Journal
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• v.42 no.1
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• pp.46-53
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• 2020

Gait analysis is an effective clinical tool across a wide range of applications. Recently, inertial measurement units have been extensively utilized for gait analysis. Effective gait analyses require good estimates of heel-strike and toe-off events. Previous studies have focused on the effective device position and type of triaxis direction to detect gait events. This study proposes an effective heel-strike and toe-off detection algorithm using a smart insole with inertial measurement units. This method detects heel-strike and toe-off events through a time-frequency analysis by limiting the range. To assess its performance, gait data for seven healthy male subjects during walking and running were acquired. The proposed heel-strike and toe-off detection algorithm yielded the largest error of 0.03 seconds for running toe-off events, and an average of 0-0.01 seconds for other gait tests. Novel gait analyses could be conducted without suffering from space limitations because gait parameters such as the cadence, stance phase time, swing phase time, single-support time, and double-support time can all be estimated using the proposed heel-strike and toe-off detection algorithm.

• Korean Journal of Applied Biomechanics
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• v.26 no.4
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• pp.333-341
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• 2016

Objective: The purpose of this study was to assess the consistency of the gliding and push-off motion for single leg skating from the first to fourteenth steps. We hypothesized that: 1) there would be no difference in stroke trajectory, step rate, and cycle rate between the left and right steps of gliding; and 2) there would be a difference in the resultant velocity of toe push-off and the horizontal velocity of the center of mass after six step push-offs. Method: The study included five male 500-m speed skaters (mean height, $1.80{\pm}0.02m$; mean weight, $76.8{\pm}3.96kg$; record, $35.83{\pm}0.30sec$; 100-m record, <9.97 sec). Data were collected from the first to fourteenth steps (40 m) and recorded using five digital JVC GR-HD1KR video cameras (Victor Co., Japan) operating at a sampling frequency of 60 fields/sec and shutter speed of 1/500 sec. For each film frame, the joint positions were digitized using the KWON3D motion analyzer. Position data were filtered with low-pass Butterworth $4^{th}$ order at the cut-off frequency of 7.4 Hz. Results: The right toe of the skating trajectories at $2^{nd}$, $5^{th}$, and $7^{th}$ strokes differed from those of the left toe. The angles of the right and left knee demonstrated unbalanced patterns from the flexion and extension legs. The step and cycle rates of the right and left leg differed from the start until 20 m. The resultant velocities of the toe at the push-off phase and of the body mass center diverged before the six push-offs. Conclusion: This study's findings indicate that the toe of skating trajectory on left and right sliding after push-off should maintain a symmetrical trajectory. The resultant velocity of toe push-off and horizontal velocity from the center of body need to be separated after about six step push-offs.

• The Journal of Korean Physical Therapy
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• v.25 no.5
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• pp.297-302
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• 2013

Purpose: This study was conducted in order to investigate the kinematic gait parameter of lower extremities with different gait conditions (level walking, stair, ramp) in hemiplegic patients. Methods: Ten hemiplegic patients participated in this study and kinematic data were measured using a 3D motion analysis system (LUKOtronic AS202, Lutz-kovacs-Electronics, Innsbruk, Austria). Statistical analysis was performed using one-way repeated measure of ANOVA in order to determine the difference of lower extremity angle at each gait phase with different gait conditions. Results: Affected degree of ankle joint in the heel strike phase showed significant difference between level walking and climbing stairs, and toe off phase showed significant difference between level walking and climbing stairs, ramps, and climbing stairs. Affected degree of knee joint showed no significant difference in all attempts. Affected degree of hip joint in the toe off phase showed significant difference between level walking, ramps and stairs, and climbing ramps. Swing phase showed significant difference between sides for level walking and stairs, climbing ramps. Affected ankle joint of heel strike and toe off, and affected hip joint of toe off and the maximum angle of swing phase in the angle was increased. Unaffected side of the ankle joint, knee joint, and hip joint showed a significant increase in walking phase. Conclusion: These findings indicate that compared with level walking, different results were obtained for joint angle of lower extremity when climbing stairs and ramps. In hemiplegia patient's climbing ramps, stairs, more movement was observed not only for the non-affected side but also the ankle joint of the affected side and hip joint. According to these findings of hemiplegic patients when climbing stairs or ramps, more joint motion was observed not only on the unaffected side but also on the affected side compared with flat walking.

• The Journal of the Korea Contents Association
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• v.15 no.8
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• pp.556-563
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• 2015

The purpose of this study was to analyzed body movement of the right and left directions relative to stance width. Seven college students(male, height $174.9{\pm}4.8cm$, weight $70.9{\pm}6.6kg$) participated in this study. For the purpose of this study, nine high-speed cameras and two force plates was utilized. Stance width was limited into small stance width(mean 42.9cm) and large stance width(mean 65cm). The results showed that (1) the small stance width took shorter time than the large stance during landing of the right feet to toe-off; (2) the small stance width was took longer movement of the right feet after split step comparing to the large stance; (3)there was no significant difference in the speed of center of gravity between toe-off and maximum speed; (4) the small stance width was greater angles to hip joint and knee joint during toe-off of the right feet comparing to the large stance; (5) the was no significant difference in values for force plates between the small stance and the large stance width during toe-off of the right feet.

• Proceedings of the KIEE Conference
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• 2006.10c
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• pp.193-195
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• 2006

In this study, we developed an active controlled ankle-foot orthosis(AAFO) which can control the dorsiflexion/plantarflexion of the ankle joint during gait to prevent foot drop and toe drag for paralysis patients. To prevent dropping foot after heel strike, ankle joint was actively controlled to minimize forefoot collision with the ground. It was also controlled to provide toe clearance and to help push-off during late stance. The 3D gait analysis was performed on two healthy subjects equipped with the developed AAFO to compare with the normal gait and the conventional AFO gait. In the developed AAFO gait, differently from the conventional AFO gait, significant push-off was observed during pre-swing and the maximum flexion moment during pre-swing phase was similar to that of normal gait. A remarkable dorsiflexion also occurred during initial swing. These results indicated that the developed AAFO could have certain clinical benefits to prevent foot drop for paralysis patients, compared to conventional AFOs.

• Korean Journal of Applied Biomechanics
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• v.30 no.4
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• pp.321-335
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• 2020

Objective: The purpose of this study was to investigate the effect of neck traction and foot type on plantar pressure distribution during walking. Method: Total of 24 data were collected from women working with a computer for more than 6 hours every day. Three groups by foot type were divided: Pes Planus, normal foot, and Pes Cavus. Depending on the foot type and cervical traction, plantar pressure variables were measured; CA, MF, PP, and CT. Each variable was divided into 12 masks. MANOVA was performed for the difference of plantar pressure variables by foot type, and a paired t-test was performed for the cervical traction within groups. Results: The total CA decreased in the Pes Planus (p<.001) and Pes Cavus (p<.05) groups. MF increased in the big toe (p<.01) and 2nd toe (p<.05) of the normal foot, and MF-3rd metatarsal decreased (p<.01). The MF-2nd toe (p<.01) and 3rd toe (p<.05) of Pes Cavus decreased. The PP decreased in 2nd toe (p<.05), 3rd toe (p<.01), and 4th toe (p<.05) of the Pes Cavus. In normal foot, the PP-3rd metatarsal (p<.05) and PP-4th metatarsal (p<.01) reduced. In Pes Planus, PP decreased in the hindfoot (p<.05). In Pes Cavus group wearing a neck-tractor, the CT-hindfoot increased (p<.05). Conclusion: There was a significant change in the plantar pressure change by foot type after neck traction. When walking with a neck-tractor, the heel impact was alleviated in the Pes Planus, and the Pes Cavus showed the smooth and effective propulsion in the push-off. Overall, weight acceptance was effectively performed when walking with neck-traction. It was also found that the neck-tractor corrects the alignment of the neck, thereby creating a more stable gait pattern.

• Korean Journal of Applied Biomechanics
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• v.13 no.3
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• pp.163-180
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• 2003

This paper aims at collecting the guantitative data of kenematic variables by analysing the gait patterns of the normal adult men and the handicapped. The gait motions were taped with 4 video cameras, the cinematographic analyses were performed by the DLT technique of three dimensional image treatment. The following results were obtained in the analysis of the variables: 1. The ratio of stance time and swing time did not show any significant difference in the groups of the normal men and the handicapped when both foot of the former and the right feet of the latter were compared. The stride peeriod time of these two groups were 1.12 and 1.11 second, respectively. 2. In the handicapped group, the step width was wider, the step length and stride length were shorter, and especially, the step length of the right foot was shorter, 3. The small vertical displacement of left toes of the handicapped group showed that the heal contact and the left midstance are almost simultaneous. 4. The two groups have almost the same horizontal displacement of the center of gravity and the same vertical rate of extension. In view of the velocity of the center of gravity the normal adults showed the constant speed of movement. However, the handicapped adults were reduced from the right midstance to the right toe-off. 5. The handicapped showed prominently low angle on the left toe-off in the ankle joint angle, they also had the tendency to walk in the patterns of extended knee in the knee joint angle. Both the handicapped and the normal had the hyperextension on the toe-off in the hip joint angle. In the back and front angle of body, both showed the slightly back-sided walking positions. 6. Both groups had the abduction of both feet in foot placement angle, but the handicapped did not show serious abduction of left midstance.

• Physical Therapy Korea
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• v.14 no.4
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• pp.66-74
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• 2007

The aim of the present study was to investigate age-related differences in stepping behavior in response to sensory perturbations of postural balance. The participants for this study were 2 healthy elderly adults (mean age=76.0) and 2 younger adults (mean age=25.5). Subjects were asked to step over a 10 cm high obstacle at self-paced speed with the right limb to land on the primary target (normal step length) that is 10 cm in diameter. However, if, during movement, the light was illuminated, then the subject had to step on the secondary target (long step length). It was planned that the onset of the light would be prior to peak Fx of swing limb, between swing peak Fx and swing toe-off, and after swing toe-off. In the younger adults these secondary visual cues were provided at mean times of 240 ms (standard deviation (SD)=11), 402 ms (SD=13), and 476 ms (SD=88) following the movement onset. Corresponding mean times for the healthy elderly were 150 ms (SD=67), 352 ms (SD=39), and 562 ms (SD=115). Results showed great changes in both group and visual cue condition in Fx ground reaction forces and temporal events following the swing toe-off. Swing limb acceleration force (Fx) and stance peak Fx1 was much greater in the young adults compared to the older adults. Both young and older adults increased stance peak Fx2 in the visual cue condition compared to normal stepping. There was no difference in stance peak Fx2 between the visual cue conditions in both groups. Similarly, the time to stance peak Fx2 was much longer for the visual cue condition than for the normal stepping. It was not different between the visual cue conditions in the young adults, but in the elderly mid and late cue was much greater than early cue. In addition, time to stance peak Fx2 and swing and stance time were much longer in the older adults compared to the young adults for the visual cue conditions. These results suggest that unlike young adults, elderly adults did not flexibly modify their responses to unexpected changes in step length while stepping over obstacles.

• Journal of the Korea Convergence Society
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• v.12 no.12
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• pp.419-425
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• 2021

The objective of this study is to verify the effects of the application of flossband to the ankles of healthy adults on the functional range of ankle and walking ability. Total 20 people participated in the experiment, and through the randomization, one foot was set up as experimental side while the other foot was set up as control side. To analyze the two factors(before/after intervention/experimental side and control side), the two way-repeated ANOVA was conducted. The significance level was set up as 0.05. In the results of this study, compared to the control side, the experimental side showed significant increase in WBLT and heel strike(p=.05). In the test before/after intervention, the experimental side showed significant increase in WBLT, heel strike, and toe off(p=.05). The control side showed significant increase in toe off(p=.05). Thus, the application of floss band on ankle joint performed in this study would be helpful for improving the functional range and walking ability in the sports & rehabilitation field.

• Archives of Plastic Surgery
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• v.34 no.5
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• pp.587-592
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• 2007

Purpose: In case of postburn flexion contracture of the fingers, skin graft, geometrical relaxation techniques, local flap, and free flap have been used. Among these procedures, full-thickness skin grafts from the inguinal area are widely used to reconstruct a postburn flexion contracture in the fingers. But there are many esthetic and functional problems in this procedure. Especially, hyperpigmentation of the skin-grafted fingers poses a troublesome problem, particularly in the patients who have dark colored skin. To solve the problem, we have used pulp graft which was harvested from the lateral aspect of great toe. In the present study, we report pulp graft, with which we have obtained a good result in the treatment of postburn flexion contracture of the fingers. Methods: Between September of 2004 and August of 2006, great toe pulp graft was performed to 20 sites of 15 patients. After release of the postburn flexion contracture using Z-plasty, the composite tissue (pulp) harvested from the lateral aspect of great toe was grafted on the raw surface. Moisture dressing with ointment and foam dressing material was performed. Stratum corneum of the graft got stripped off in two to four weeks after pulp graft. The color of the pulp graft was slightly reddish, then it became similar to the adjacent tissue. Results: There was complete take in all the patients who were treated with pulp graft. Great toe pulp graft provided similar color and texture to the adjacent skin, high rate of graft take, and left only a minimal scar at donor site. Conclusion: Thick keratin layer and inelastic nature of the pulp make this type of the graft much easier and simpler, and ensure a better take. Pulp graft is useful method for the reconstruction of the postburn flexion contracture in fingers.