• 대한기계학회논문집A
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• 제41권8호
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• pp.771-782
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• 2017

본 논문은 노약자들의 발목근력보조를 위한 착용형 로봇에 대해서 서술하였다. 기존 착용형 로봇들은 보행 시 필요한 근력을 보조하기 위해 대부분 모터와 감속기를 사용하였다. 하지만 모터와 감속기의 조합은 무게가 무거울 뿐만 아니라 감속기 치차의 마찰때문에 실제 사람의 근육과 달리 강성과 토크를 동시에 제어하기 어려운 한계가 있다. 따라서 본 연구에서는 모터/감속기 조합보다 가볍고 안전하며 근력을 보조하는 힘을 충분히 발휘할 수 있는 Mckibben 공압 근육을 사용하였다. 발목의 피칭 모션에 이용되는 종아리 가자미근 및 앞정강근의 힘을 한 쌍의 공압 근육을 사용한 상극구동으로 보조하였으며, 상극구동제어를 위해 상극구동 모델 파라미터들을 실험적으로 도출하였다. 사용자의 보행의지를 판단하고자 발바닥에 부착된 압력변위센서로 압력과 압력중심위치를 측정하여 발바닥의 하중과 발목토크를 계산하였고, 이를 기반으로 공압 근육 관절의 강성과 토크를 동시에 제어하였다. 최종적으로, 트레드밀에서 근전도 신호를 측정하여 발목근력보조로봇의 성능을 실험적으로 입증하였다.

• 한국전문물리치료학회지
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• 제31권1호
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• pp.18-28
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• 2024

Background: Lateral instability of the ankle is one of the most common causes of musculoskeletal ankle injuries. The peroneus longus (PL) and peroneus brevis (PB) contribute to ankle stability. In early rehabilitation, isometric exercises have been selected for improvement of ankle stability. To effectively train the peroneal muscles during eversion, it is important to consider ankle and body posture. Objects: This study aimed to compare activation of the PL, PB, and biceps femoris (BF) muscles during eversion in different ankle postures (neutral [N], plantarflexed [PF]) and body postures (sitting and side-lying). Methods: Thirty healthy individuals with no history of lateral ankle sprains within the last 6 months were included in the study. Maximal isometric strength of eversion and muscle activation were measured simultaneously. Muscle activation at submaximal eversion was divided by the highest value obtained from maximal isometric eversion among the four postures (percent maximal voluntary isometric contraction [%MVIC]). To examine the differences in muscle activation depending on posture, a 2 × 2 repeated measures analysis of variance (ANOVA) was conducted. Results: There were significant interaction effects of ankle and body postures on PL muscle activation and evertor strength (p < 0.05). The PL muscle activation showed a significantly greater difference in the side-lying and PF conditions than in the sitting and N conditions (p < 0.05). Evertor strength was greater in the N compared to the PF condition regardless of body posture (p < 0.05). In the case of PB and BF muscle activation, only the main effects of ankle and body posture were observed (p < 0.05). Conclusion: Among the four postures, the side-lying-PF posture produced the highest muscle activation. The side-lying-PF posture may be preferred for effective peroneal muscle exercises, even when considering the BF muscle.

• 대한인간공학회지
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• 제29권5호
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• pp.789-795
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• 2010

This study aimed to investigate the effect of differing heel height on static balance and muscle activation of ankle joint during standing. Twenty-one young females volunteered to participate in this study. To measure balance function and EMG activity of tibialis anterior and gastrocnemius muscles, the subjects were asked to perform 1-min standing with eyes open and closed state under 3 different heel heights: barefoot, 3cm, and 7cm each. During the standing, postural sway distance and area, and EMG activity of tibialis anterior and gastrocnemius muscles were significantly augmented with increasing heel height (p<0.05). For comparison between eyes open and closed in terms of postural sway area and EMG activity of tibialis anterior muscle, barefoot and 7cm height conditions respectively showed significant differences as well. The findings indicate that high-heeled shoes may have disadvantages in maintaining balance function because of extra-muscular effort of ankle joint. This study provides useful information that will inform future studies on how heel height affects muscle activity around the ankle joint in aspects of static and dynamic balance.

• The Journal of Korean Physical Therapy
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• 제35권2호
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• pp.53-57
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• 2023

Purpose: The purpose of this study was to compare the changes in the muscle activation of the quadriceps muscle (rectus femoris, vastus lateralis, vastus medialis) during the stand-to-sit (StandTS) movement according to the plantar flexion angle of the ankle joint. Methods: A total of 22 healthy young females participated in this study. During the StandTS under the three conditions (plantarflexion angle 0°, 20°, and 45° of the ankle), electromyography (EMG) data (% maximum voluntary iso¬metric contraction) of the rectus femoris, vastus lateralis, and vastus medialis were recorded using a wireless surface EMG system. Results: There was a significant difference in the muscle activation of rectus femoris, vastus lateralis, and vastus medialis according to the plantar flexion angle (0°, 20°, and 45°) of the ankle. The muscle activation of the quadriceps was the highest at a 45° angle of plantarflexion and the lowest at 0°. One-way repeated ANOVA was used to analyze the muscle activation data of the lower extremity muscles according to the angle of the ankle joint. Conclusion: Based on the results of our study, it was confirmed that the muscle activity of the quadriceps can be increased even in the StandTS movement, which involves the eccentric contraction of the quadriceps muscle. This suggests that maintaining a plantar flexion posture for a long time, say by wearing high-heeled shoes, can quickly cause muscle fatigue in the lower-limb muscles, which can cause a decrease in balance ability leading to falls.

• 한국운동역학회지
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• 제25권4호
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• pp.401-412
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• 2015

Objective : The purpose of this study is to evaluate the effects of hip joint exercises and orthotics on RCSP, ankle's range of motion, and core muscle strength of middle school students with pes planus. Method : Out of the original pool of 200 students, 60 students with pes planus (RCSP < -2) were selected for the study. The selected 60 students were then divided into four groups. The first group was a combined orthotics and exercise group (12 students), the second was the orthotics-only group (9 students), the third was the exercise-only group (8 students), and the last was the control group (10 students). Exercise groups worked out twice a week for 60 minutes per session over 8 weeks. The independent variables were corrective hip joint exercises and orthotics. The dependant variables consisted of kinematic and kinetic variables. The kinematic variables were RCSP, and ankle's range of motion (dorsiflexion and plantarflexion). The kinetic variables were muscles forces that consist in core muscle strength, which are hip joint adduction, abduction, and flexion muscles forces. Statistical analysis was performed via SPSS 18.0 with multivariate analysis of covariance (MANCOVA) and a paired t-test was used. Results : The left foot was more responsive to the treatments, both exercise and orthotics, than the right foot. RCSP improved significantly in the left foot for the first and third groups. Only the first group significantly improved hip joint adduction, abduction, and flexion muscles' strengths. As for the ankle's range of motion of the left foot, plantarflexion showed improvement when treated with exercise, orthotics, or both. Conclusion : This study found that exercise is more effective in correcting RCSP and foot orthotics is more effective in reinforcing core muscle strength. Future studies should expand on these results to examine the relationship between the ankle, hip, and pelvis.

• 대한물리의학회지
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• 제6권3호
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• pp.311-321
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• 2011

Purpose : The purpose of this study was to determine effect of Medical Exercise therapy on walking ability and ankle muscles activation after stroke. Method : Participants were randomly divided into either MET training group(n=12) and control group(n=12). All of participants had been receving a traditional rehabilitation program, 5 days a week. MET training group have additionally undergone for six weeks, 3 days a week, the MET program. But control group was not received any additional program except the traditional rehabilitation program. The 10 mWT, F8WT and 2 MWT to measure walking ability were carried out twice before and after training. Muscular activity of the ankle was estimated by analyzing the RMS of action potential for EMG in terms of tibialis anterior muscle(TA), soleus(SO), gastrocnemius medial head(GM), gastrocnemius lateral head(GL). Rresults : At the walking ability, MET training group demonstrated a significant improvememt in the score of the 10 mWT(p<0.001), 2 MWT(p<0.05), but F8WT was not significant improvement(p>0.05). At the ankle muscle activation, MET training group demonstrated a significant improvememt in the RMS of the TA(p<0.01) and SO(p<0.05) but GM(p>0.05) and GL(p>0.05) were not significant improvement. Conclusion : From these results of this study, MET training for 6 weeks has an effect on improvement of walking ability and ankle muscles activation after stroke.

• 대한의용생체공학회:의공학회지
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• 제30권6호
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• pp.521-528
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• 2009

This study is about to evaluation of postural stability according to characteristics of electrical stimulation on the ankle muscles. We measured body sway(center of pressure, COP) when various parameters of electrical stimulation was applied to ankle muscles in stable and unstable posture. Subjects consisted of 10 young adults, and electrical stimulation was delivered on right and left of tibialis anterior and Achilles tendon. The body sway was measured during electrical stimulation of three duty cycle and frequencies in stable posture and three amplitudes of sensory threshold in unstable posture. Consequently, the COP Shift is higher during electrical stimulation of 1/30(duty ratio) and 100Hz(frequency) in stable posture. In unstable posture, 100% amplitude of sensory threshold induced postural stability. These findings are important for the rehabilitation system of postural stability and the use of electrical stimulation as somatosensory information.

• The Journal of Korean Physical Therapy
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• 제34권6호
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• pp.321-325
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• 2022

Purpose: Temporomandibular disorder (TMD) is a condition defined as pain and dysfunction of temporomandibular joints and masticatory muscles. Abnormal interconnections between temporomandibular muscles and cervical spine structures can cause the changes of postural alignment and balance ability. The aim of this study was to investigate changes in static balance ability in subjects with painrelated TMD. Methods: This study conducted on 25 subjects with TMD and 25 control subjects with no TMD. Pressure pain thresholds (PPTs) of the masseter and temporalis muscles were measured using a pressure algometer. Static balance ability was assessed during one leg standing using an Inertial Measurement Unit (IMU) sensor. During balance task, the IMU sensors measured motion and transfer movement data for center of mass (COM) motion, ankle sway and hip sway. Results: PPTs of masseter and temporalis muscles were significantly lower in the TMD group than in the control group (p<0.05). One leg standing, hip sway, and COM sway results were significantly greater in the TMD group (p<0.05), but ankle sways were not different between group. Conclusion: We suggest pain-related TMD is positively related to reduced PPTs of masticatory muscles and to static balance ability. These results should be considered together with global body posture when evaluating or treating pain-related TMD.

• 대한통합의학회지
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• 제5권4호
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• pp.49-55
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• 2017

Purpose : In this study we tested the hypothesis that eucommia ulmoides (EU) extract would improve disuse-induced muscle atrophy following hindlimb immobilization. Method : The hindlimb immobilization was performed with casting tape to keep the left ankle joint in a fully extended position. The rats in EU treated group were orally administrated with eucommia ulmoides water extract. After 2 weeks of immobilization, all animals were sacrificed, and the whole gastrocnemius muscles were dissected from both legs. The morphology of right and left gastrocnemius muscles in both EU and control groups were assessed by hematoxylin and eosin staining. Results : Eucommia ulmoides extract represented the significant protective effects against the reductions of the gastrocnemius muscles weight and average cross section area to compared with Control group. Conclusion : Eucommia ulmoides has protective effects against immobilization induced muscle atrophy.

• 한국운동역학회지
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• 제22권2호
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• pp.219-228
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• 2012

The purpose of this study was to investigate how induced fatigue of the ankle joint muscles affects the capability and recovery of postural control during single-leg stance in healthy adults. The study population included 22 randomly recruited men and women. Postural control was performed on single-leg stance with eyes open. Ankle joint muscle was fatigued by repeated heel raises. According to the results of this study, for the anteroposterior variables, both men and women showed significantly increased center of mass velocity and decreased center of pressure 95% edge frequency immediately after fatigue. For the mediolateral variables, both men and women showed significantly increased center of mass velocity and decreased center of pressure 95% edge frequency immediately after fatigue. For the total variables, both men and women showed significantly increased center of mass averaged-velocity immediately after fatigue, and also, the center of pressure 95% confidence ellipse area significantly increased in women. Postural control variables were not significantly different for men and women at any time (Pre, P0, P10, and P20). In conclusion, the gender does not affect the capability and recovery after induced fatigue of ankle joint muscles. The effect of fatigue found for the anteroposterior and the mediolateral variables in both men and women. Furthermore ankle joint muscle fatigue led to change of postural control strategy from an ankle joint strategy towards a hip joint strategy. These changes are believed to damage postural control. The ankle joint muscle recovered from fatigue within 20 min during single-leg stance.