• 한국운동역학회지
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• 제16권1호
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• pp.65-79
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• 2006

The purpose of this study was firstly to investigate correctional function of custom semi-rigid foot orthotics for excessively pronated people during gait by observing comfort, navicular movement and leg muscles' activity according to short-term and mid-term wearing duration and secondly to understand positive and/or negative point of view of a recently proposed paradigm related to foot orthotics more profoundly. Sixteen subjects who showed excessive pronation at navicular drop test were recruited for this study. Custom semi-rigid foot orthotics were made fitting for foot characteristics of the subjects by podiatry division of Otto Bock Korea company. While wearing the foot orthotics for two months, comfort of wearing were questioned and vertical navicular movement and electromyography of leg muscles during gait were measured at the condition of both immediately after and 2 months after including a control condition, respectively. The subjects were required to walk on a treadmill at the speed of 1.5m/s and four digital video camera filmed the movement of navicular process at the speed of 60 frames/s. In conclusion, in excessively pronated group continuous increase of comfort from short-term to mid-term wearing of custom foot orthotics is assumed to be closely related with short-term and mid term correctional action, of which are consisted the decrease of the range of navicular drop and navicular raisins- the faster timing of minimum navicular position occurring, and the decrease of leg muscles' activities. This conclusion could lead to positively accept new paradigm related to foot orthotics suggested by Nigg and the author suggest that in the future study the variable which could observe navicular movement would be one of major variables to study preferred path of skeleton in the paradigm.

• 한국전문물리치료학회지
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• 제13권1호
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• pp.24-31
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• 2006

The purpose of this study was to identify the effect of the hip internal rotation on gluteal and erector spinae muscle electromyographic (EMG) activity during treadmill walking. Eleven healthy subjects were recruited. All subjects performed treadmill walking while maintaining the hip in neutral position (condition 1) and in internal rotation (condition 2). Surface EMG activity was recorded from four muscles (gluteus maximus (GM), gluteus medius (GMED), tensor fascia latae (TFL), and erector spinae (ES)) and the hip internal rotation angle was measured using a three dimensional motion analysis system. The gait cycle was determined with two foot switches, and stance phase was normalized as 100% stance phase (SP) for each condition using the MatLab 7.0 program. The normalized EMG activities according to the hip rotation (neutral or internal rotation) were compared using a paired t-test. During the entire SP of treadmill walking, the EMG activities of GM in condition 1 were significantly greater than in condition 2 (p<.05). The EMG activities of TFL and ES in condition 2 were significantly greater than in condition 1 (p<.05). The EMG activities of the GMED in condition 1 were significantly greater than in condition 1 (p>.05) except for 80~100% SP. Further studies need randomized control trials regarding the effect of hip internal rotation on the hip and lumbar spine muscle activity. Kinetic variables during gait or going up and down stairs are also needed.

• 한국운동역학회지
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• 제17권3호
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• pp.147-154
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• 2007

This study's purpose is to investigate the effects on leg muscle activity caused by perturbation, using a trapdoor system during the support phase of gait for healthy adults (n = 6, height $177.5{\pm}5.5cm$, weight $81.0{\pm}9.5kg$, age $30.0{\pm}3.3yrs$). The trapdoor had the functional ability of causing inversion or eversion. The release time for the trapdoor was specified for two times, 0.3 and 0.5 seconds after heel contact. While altering these variables, EMG was recorded for the leg muscles (rectus femoris, biceps femoris, vastus lateralis, tibialis anterior, gastrocnemius, soleus). The following conclusions were derived. The steptime was longer for the 0.5s eversion than 0.3s inversion condition. So in order to regain stability after the perturbation the unsupporting leg reached forward rapidly. This quick reflex can be observed through the center of pressure (COP) and its rapid change in direction. The gastrocnemius was activated throughout the total experiment. There was a low amount of activity recorded in the rectus femoris, vastus lateralis and tibialis anterior except for the condition of inversion 0.3s. For most of the conditions, the highest average EMG peak values were recorded during the condition of inversion 0.3s. The iEMG patterns were similar for the conditions of inversion 0.3s and eversion 0.3s. To cope with the rapid change in these conditions, the biceps femoris was activated. During the experiment except for the condition of normal gait, the activity of the soleus and gastrocnemius was relatively high. Therefore, to prevent injury from perturbation of the lower leg strengthening of the soleus and gastrocnemius is required. Likewise to prevent injury to the thigh strengthening for the biceps femoris.

• 한국운동역학회지
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• 제23권2호
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• pp.179-187
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• 2013

This case study was conducted to determine the effects of water exercise on the foot pressure distribution (FPD) of persons who have a hemiplegia. A 43-year old female with hemiplegia acquired at the age of 3 years was selected from a local disability program. A 12-week water exercise program (60 min. per session and twice a week) focusing on gait training was developed and implemented as the intervention of this study. A recent product of the Pedar-X (Novel, Germany) was used to measure the FPD of hemiplegic gait before and after the intervention. Variables considered in this study included the average pressure (AP), contact area (CA), maximum pressure (MP), ground reaction force (GRF), and center of pressure (COP). The data collected were analyzed via the descriptive statistics and qualitative analyses on the graphical presentations of the FPD. Results revealed that the AP and CA of the hemiplegic foot was considerably increased before and after the intervention. Similar results were also found in the MP and GRF. Additionally, the graphical route of the COP related to hemiplegic foot was changed in a positive way after the intervention. It can be concluded that water exercise may be beneficial to restore hemiplegic gait. Limitations related to measurement and generalizability are further discussed.

• 한국운동역학회지
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• 제27권1호
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• pp.53-58
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• 2017

Objective: The purpose of this study was to compare the accuracy of stride time and stride length provided by a commercial APDM inertial sensor system (APDM) with the results of three dimensional motion capture system (3D motion) during treadmill walking. Method: Five healthy men participated in this experiment. All subjects walked on the treadmill for 3 minutes at their preferred walking speed. The 3D motion and the APDM were simultaneously used for extracting gait variables such as stride time and stride length. Mean difference and root mean squared (RMS) difference were used to compare the measured gait variables from the two measurement devices. The regression equation derived from the range of motion of the lower limb was also applied to correct the error of stride length. Results: The stride time extracted from the APDM was almost the same as that from the 3D motion (the mean difference and RMS difference were less than 0.0001 sec and 0.0085 sec, respectively). For stride length, mean difference and RMS difference were less than 0.1141 m and 0.1254 m, respectively. However, after correction of the stride length error using the derived regression equation, the mean difference and the RMS difference decreased to 0.0134 m and 0.0556 m or less, respectively. Conclusion: In this study, we confirmed the possibility of using the temporal variables provided from the APDM during treadmill walking. By applying the regression equation derived only from the range of motion provided by the APDM, the error of the spatial variable could be reduced. Although further studies are needed with additional subjects and various walking speeds, these results may provide the basic data necessary for using APDM in treadmill walking.

• 한국운동역학회지
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• 제28권1호
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• pp.19-27
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• 2018

Objective: This study aimed to analyze the effects of freezing of gait on spatiotemporal variables, ground reaction forces (GRFs), and joint moments during the sit-to-walk task at the preferred and maximum speeds in patients with Parkinson's disease (PD). Method: The subjects were classified by a neurologist into 12 freezers, 12 non-freezers, and 12 controls. Sit-to-walk parameters were measured during three repetitions of the task in a random order at the preferred and maximum possible speeds. Results: In the sit-to-walk task at the preferred speed, the freezers and non-freezers exhibited a higher peak anterior-posterior GRF (p<0.001) in the sit-to-stand phase and lower step velocity (p<0.001), step length (p<0.001), and peak anterior-posterior GRF (p<0.001) in the first-step phase than the controls. The freezers had higher peak anterior-posterior GRF (p<0.001) and peak moment of the hip joint (p=0.008) in the sit-to-stand phase than the non-freezers. In the sit-to-walk phase at the maximum speed, the freezers and non-freezers had lower peak moment of the hip joint (p=0.008) in the sit-to-stand phase than the controls. The freezers and non-freezers displayed lower step velocity (p<0.001) and peak anterior-posterior GRF (p<0.001) in the first-step phase than the controls. The freezers showed higher peak moments of the hip joint in the sit-to-stand phase than the non-freezers (p=0.008). Conclusion: The PD patients had reduced control ability in sit-to-stand motions for efficient performance of the sit-to-walk task and reduced performance in the sit-to-walk task. Furthermore, the freezers displayed reduced control ability in the sit-to-stand task. Finally, the PD patients exhibited a lower ability to control dynamic stability with changes in speed than the controls.

• 한국산학기술학회논문지
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• 제14권1호
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• pp.344-350
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• 2013

본 연구의 목적은 파킨슨병 환자의 청각 신호에 따른 보행 시, 상지 스윙의 비대칭과 진폭에 미치는 영향을 알아보기 위함이다. 연구의 대상자는 초기 파킨슨병으로 진단받은 14명의 환자로, 청각 신호(빠른 속도, 일반적인 속도, 느린 속도)를 무작위 순서로 제공하여 보행을 실시하였다. 청각 신호 속도는 전자 메트로놈을 이용하여 대상자의 자연스러운 보행 속도보다 ${\pm}20%$ 속도를 적용하였다. 각각의 속도에 따른 청각 신호를 적용한 보행을 실시하는 동안, 동작분석기를 사용하여 보행 시 상지 스윙의 운동학적 변수를 비교 분석하였다. 정상 속도의 보행 시 파킨슨병 환자의 양측 상지 스윙 진폭의 비교에서는 더 많은 영향을 받은 쪽(MAS)의 상지 스윙 진폭에서 유의한 감소가 나타났다(p<.05). 청각 신호 속도에 따른 보행 시의 비교에서는 빠른 속도의 청각 신호를 적용한 보행 시 상지 스윙의 유의한 증가가 나타났다(p<.05). 본 연구의 결과를 통해 파킨슨 환자의 보행 시 양측 상지 스윙의 비대칭을 확인할 수 있었으며 또한 보행 시 빠른 청각 신호를 적용하는 경우, 파킨슨병 환자의 상지 스윙을 증가시켜 자연스러운 보행양상을 유도할 수 있으므로 중재 시 필요에 따라 적절한 속도의 청각 신호를 적용하여 보행훈련에 적용할 수 있을 것으로 생각된다.

• 한국운동역학회지
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• 제18권2호
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• pp.49-58
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• 2008

본 연구의 목적은 트레드밀 보행 시, gait dynamics 측면에서 보행의 속도 변화와 인지과제 수행 시 보행 변인의 가변성(variability)을 알아보고자 하는 것이다. 실험은 인지과제의 동시수행 유/무에 따른 5가지 속도(선호속도의 80%, 90%, 100%, 110% and 120%)에 의한 보행 실험으로 구성되었다. 인지과제의 종류는 학습기능이 없는 인지과제(2-back task)를 수행하였다. 인지과제는 피험자의 트레드밀 보행 시, 3m 앞에 놓여진 스크린에 주어지고 무선마우스를 통해 응답하는 형태로 구성되었다. 실험의 모든 과정은 3차원 동작분석기를 통해 동작데이터를 획득하였다. 이를 통해, 5가지 보행 시간 변인과 3가지 공간 변인을 추출하였다. gait dynamics 측면의 분석을 위해, 가변성의 크기를 살펴볼 수 있는 방법인 분산계수(coefficient of variance)와 변동량의 구조적 자기 유사성을 추론할 수 있는 detrended fluctuation analysis (DFA)를 사용하였다. 그 결과 보행 속도 변화에 따라 보행 변인의 평균값과 분산계수에서 통계적 유의한 차이가 발생하였고, 인지과제의 수행 유/무에 따라서는 DFA에서 통계적인 차이가 발생하였다. 이는 인지과제의 수행에 의해 보행의 발생과 조절 능력에 영향을 끼쳤다고 추론할 수 있다. 본 연구 결과를 명백히 하기 위해 더 많은 수의 피험자 실험과 추가 실험이 필요할 것이다.

• 한국응용과학기술학회지
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• 제38권3호
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• pp.762-770
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• 2021

본 연구의 목적은 신체 전신 운동인 맵시 운동 프로그램을 중년여성들에게 8주간 적용하여 보행 시 수직 지면반력 크기, 발생시간, 압력 중심 요인들에 미치는 영향을 분석하는데 있었다. 본 연구의 피험자로 운동군 13명(연령, 41±4.4 세; 신장, 162.5±5.8 cm; 체중, 57.8±6.7 kg; 신체질량지수, 21.9±2.4 kg/m²), 대조군 12명(연령, 41.1±5.6 세; 신장, 160.9±5.5 cm; 체중, 576.2±8.1 kg; 신체질량 지수, 21.7±2.9 kg/m²) 총 25명이 참여하였다. 운동군은 7영역 23종 77동작의 맵시운동 프로그램을 8주간 주 3회 실시하였다. 보행 시 지면반력 요인들의 검증을 위하여 Two-way repeated measures ANOVA를 실시하였으며, 사후검증은 bonferroni adjustment로 분석하였다(a=.05). 맵시 운동 프로그램의 운동군은 보행 시 FMWA와 FPO 시점까지의 소요 시간, FMWA와 FPO에서 발생한 수직 지면반발력 그리고 AP 방향 COP의 RMS 요인들에서 대조군에 비해 상대적으로 큰 수치를 나타내었다. 그러므로 8주간의 맵시운동 프로그램은 보행을 수행하는 중년여성들의 가속과 감속 운동 기능을 향상시킨 것으로 나타났다.

• 한국운동역학회지
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• 제22권3호
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• pp.261-268
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• 2012

The purpose of this study was to qualitatively analyze pressure intensity and the center of pressure(COP) trajectory according to shoe type. Subjects were ten first-year female university students. The EMED-AT 25/D(Novel, Germany) was used to measure pressure intensity and COP trajectory. The COP Excursion Index(CPEI) was used for within subject test design. Independent variables were bare feet and six types of shoes. Dependent variables were center of pressure trajectory and pressure intensity. Barefeet and five toed shoes had a similar pressure intensity and COP trajectory. COP trajectory for all other shoe types showed a medial wobble at the heel. Pressure intensity for all other shoe types was related to the structure of the shoes. In conclusion, different shoe types can not only affect gait, but they can also influence foot deformities, pain, and dysfunction.