• 한국운동역학회지
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• 제24권2호
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• pp.139-149
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• 2014

The purpose of this study was to evaluate the effect of angle change of forefoot's adhesive outsole on the electromyographic activity (EMG) of the erector spinae and selected lower limbs muscle during downhill walking over $-20^{\circ}$ ramp. Thirteen male university students (age: $25.4{\pm}3.9$ yrs, height: $176.2{\pm}5.1$ cm, weight: $717.4{\pm}105.0$ N) who have no musculoskeletal disorder were recruited as the subjects. To assess the myoelectric activities of selected muscles, six of surface EMG electrodes with on-site pre-amplification circuitry were attached to erector spinae (ES), rectus femoris (RF), biceps femoris (BF), tibialis anterior (TA), lateral gastrocnemius (LG), and medial gastrocnemius (MG). To obtain maximum EMG levels of the selected muscles for normalization, five maximum effort isometric contraction were performed before the experimental trials. Each subject walked over $0^{\circ}$ and $20^{\circ}$ ramp with three different forefeet's EVA outsole (0, 10, $20^{\circ}$) in random order at a speed of $1.2{\pm}0.1$ m/s. For each trial being analyzed, five critical instants and four phases were identified from the recording. The results of this study showed that the average muscle activities of MG and LG decreased in $20^{\circ}$ shoes compared to $0^{\circ}$ and $10^{\circ}$ ones in the initial double limb stance (IDLS). In initial single limb stance (ISLS) phase, the average muscle activities of ES increased with the angle of forefoot's adhesive outsole, indicating that the increment of shoes' angle induce upper body to flex anteriorly in order to maintain balance of trunk. In terminal double limb stance (TDLS) phase, average muscle activities of TA significantly increased in $20^{\circ}$ outsole compared to $0^{\circ}$ and $10^{\circ}$ ones. There was no external forces acting on the right foot other than the gravity during terminal single limb stance (TSLS) phase, all muscles maintained moderate levels of activity.

• 한국운동역학회지
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• 제15권2호
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• pp.41-55
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• 2005

In this study, weight carrying pattern analysis and comparison method of four foot region were suggested. We used three types of club(driver, iron7, pitching wedge). This analysis method can compare between top class golfer and beginner. And the comparison data can be used to correct the swing pose of trainee. If motion analysis system, which can measure the swing speed and instantaneous acceleration at the point of hitting a ball, is combined with this plantar foot force analysis method, new design development of golf shoes to increase comfort and ball flight distance will be available. 1. Regional change of force acting, in address, is evenly distributed on both feet. In back swing top, 76% on right foot, 75% on left foot as impact, and 86% on left foot as finish. As regional force acting, in address, pros get high marks on rare and inside of right foot and rare and outside for amateurs. In back swing top, it is higher as fore and inside of left foot, pros as rare part of right foot and amateurs as forefoot. In impact, it is higher for pros and amateurs in outside and rare part of left foot and fore and inside of right foot. In finish, for both pros and amateurs, it is higher for outside and rare parts of left foot. 2. For each club, forces are evenly distributed on both feet in address. In back swing top, the shorter a club is, the higher impact on right foot and the higher finish distribution on left foot. For all the clubs used, in each region, pros get higher on rare and inside of right foot and as amateurs on rare and outside of left foot in address. In back swing top, for all clubs, pros get higher on rare and outside of right foot as fore and outside for amateurs. In impact acting, for all clubs, rare and outside of left foot get higher. In finish, force concentrates on rarefoot. 3. On both feet force, right foot forces of amateurs is higher than those of pros in back swing top. In impact and finish, pros get higher on left foot.

• 한국운동역학회지
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• 제26권3호
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• pp.285-292
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• 2016

Objective: This study collected data on muscle fatigue and ground reaction force during walking to provide a basis for development of custom-fitted outdoor walking shoes. The study analyzed an upright body exercise program using spine stabilization technique to determine the effect on foot plantar pressure in archers, demonstrate the effectiveness of upright body exercise, and develop a new, effective, and efficient training program. Method: A 12-week upright body exercise program was evaluated for the effect on plantar pressure in archers. Ten prize-winning archers (3 men, 7 women) in B metropolitan city, each with ${\geq}10years$ of experience, were given an explanation of the content and purpose of the program, and provided informed consent. Upright body exercise was performed 3 times a week for 12 weeks. A resistive pressure sensor was used to measure foot plantar pressure distribution and analyze quantitative information on variation in postural stability and weight shifting in dynamic balance during shooting, as well as plantar pressure in static balance with the eyes open and closed. Results: There were no significant differences in foot plantar pressure before and after participation in the exercise program. There was no statistically significant difference in foot plantar pressure in static balance with the eyes open or closed, or in foot plantar pressure in dynamic balance during shooting. Conclusion: An upright body exercise program had positive effects on foot plantar pressure in static and dynamic balance in archers by reducing body sway and physical imbalance during shooting and with eyes closed. This program is expected to help archers improve their posture and psychological state, and thereby improve performance.

• 한국운동역학회지
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• 제26권1호
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• pp.135-142
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• 2016

Objective: The purpose of this study was to investigate the acute effect of walking on high heels on the behavior of fascicle length and activation of the lower limb muscles. Methods: Twelve healthy inexperienced high heel wearers (age: $23.1{\pm}2.0yr$, height: $162.4{\pm}4.9cm$, weight: $54.4{\pm}8.5kg$) participated in this study. They walked in high heels (7 cm) and barefoot on a treadmill at their preferred speed. During the gait analysis, the lower limb joint kinematics were obtained using a motion analysis system. In addition, the changes in fascicle length and the level of activation of the medial gastrocnemius (MG) were simultaneously monitored using a real-time ultrasound imaging technique and surface electromyography, respectively. Results: The results of this study show that the MG fascicle operates at a significantly shorter length in high heel walking ($37.64{\pm}8.59mm$ to $43.99{\pm}8.66mm$) in comparison with barefoot walking ($48.26{\pm}9.02mm$ to $53.99{\pm}8.54mm$) (p < .05). In addition, the MG fascicle underwent lengthening during high heel walking with relatively low muscle activation while it remained isometric during barefoot walking with relatively high muscle activation. Conclusion: Wearing high heels alters the operating range of the MG fascicle length and the pattern of muscle activation, suggesting that prolonged wearing of high heels might induce structural alterations of the MG that, in turn, hinder normal functioning of the MG muscle during walking.

• 한국응용과학기술학회지
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• 제37권2호
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• pp.206-213
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• 2020

보행 시 하이힐 굽 높이에 따른 구간별 차이를 비교하고, 하지관절의 가동범위가 보행 시간에 미치는 영향을 알아보고자 하였다. 20대 여대생 10명이 연구에 참여하였고, 굽 높이에 따라 3차원 보행분석을 통하여 변인을 산출하였다. 통계방법으로 세가지 굽높이에 따른 차이는 일원변량분석을 실시하였고, 보행시간이 하지관절에 미치는 영향은 다중회귀분석을 실시하였다. 연구결과로 보행 시 구간 2는 굽이 높을수록 보행시간이 길게 나타났지만, 구간 3은 굽이 높을수록 보행시간이 짧게 나타났다. 보행시간이 하지관절 가동범위에 미치는 영향을 분석한 결과 구간 2는 1 cm에서 발목관절, 무릎관절, 5 cm는 발목관절의 가동범위가 클수록 보행시간이 길어졌다. 구간 3은 1 cm에서 고관절 가동범위가 클수록 보행시간이 길어졌고, 10 cm는 발목관절 가동범위가 작을수록 보행시간이 길어졌다. 따라서 굽 높이 신발의 경우 발목관절의 제어가 중요성이 변인으로 판단된다.

• 한국운동역학회지
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• 제15권1호
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• pp.75-89
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• 2005

D. K. LEE, J. S. LEE, B. J. LEE, H. S. LEE, Y. J. KIM, S. B. PARK, J. P. JOO. Plantar foot pressure analysis during golf swing motion using plantar foot pressure measurement system. Korean Journal of Sport Biomechanics, Vol. 15, No. 1, pp. 75-89, 2005. In this study, weight carrying pattern analysis and comparison method of four foot region were suggested. We used three types of club(driver, iron7, pitching wedge). This analysis method can compare between top class golfer and beginner. And the comparison data can be used to correct the swing pose of trainee. If motion analysis system, which can measure the swing speed and instantaneous acceleration at the point of hitting a ball, is combined with this plantar foot force analysis method, new design development of golf shoes to increase comfort and ball flight distance will be available. 1. Address acting, forces concentrated in rare foot regions and lateral foot of right foot. Back swing top acting, relatively high force occurred in medial forefoot region of left foot and forefoot region of right foot. Impact acting, high force value observed in the lateral rarefoot region of left foot and medial forefoot region of right foot. Finish acting, force concentration observed on the lateral region and rarefoot region of left foot. 2. Forces were increased in address of right foot with clubs length increased. All clubs, back swing top acting, high force value observed in the lateral forefoot region of right foot. All clubs, in impact, high force value observed in the lateral rarefoot region of left foot and medial forefoot region of right foot. Finish acting, force concentration observed on the rarefoot region in driver and lateral foot region in iron on left foot. 3. Right foot forces distribution were increased in address, back swing top and left foot force distribution were increased in impact, finnish

• 한국운동역학회지
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• 제21권4호
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• pp.479-486
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• 2011

This study determined the effects of the height and the quality of the material of popular heel-up insole on mean plantar foot pressure during walking. Seven healthy college students who are studying at S university in Busan were as participants in this study. After sufficiently explaining about the research to the subjects before the experiment, mean plantar foot pressures were examined using F-Scan Pressure Measure System 5.23 for the gait with shoes inserted insole and the data were compared among the height and the quality of material of insoles. In the result, there was a difference significantly in the mean plantar foot pressure followed the height of insoles both left and right. Especially, mean plantar foot pressure in left indicated significantly lower in 3 cm and 5 cm insoles than in 0 cm and 1 cm insoles. Also mean plantar foot pressure in right showed significantly lower in 3 cm and 5 cm insoles than in 0 cm, and indicated significantly lower in 5 cm insoles than in 1 cm and 3 cm insoles. The mean plantar foot pressure followed the quality of the material of insoles were different significantly. In left, the mean plantar foot pressure of urethane poly-acetyl insole was lower significantly than urethane poly-acetyl inserted air insole, power-gel insole and jelly insole. And the mean plantar foot pressure of urethane poly-acetyl insole was lower significantly than power-gel insole and jelly insole in right. We showed that 3 cm and 5 cm insoles in the height of insoles and Urethane poly-acetyl insole in the quality of material were suitable to reduce a fatigue which is felt in plantar foot during the walking.

• 한국운동역학회지
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• 제18권2호
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• pp.115-124
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• 2008

본 연구는 행군 시 발보장구 착용이 하지 근육 활동에 미치는 영향을 알아보는데 목적이 있다. 과회내족과 정상족을 선정하여 트레드밀에서 4.5km/h의 속도로 걷게 하였고 이때 근전도기를 이용하여 하지근육의 근육신호를 수집, 분석하였다. 수집한 데이터를 평균적분근전도와 스펙트럼 분석을 통해 근활성도와 피로도를 알아보았고 SPSS 12.0을 이용하여 통계분석하였다. 실험 결과는 과회내족이 정상족보다 행군 시 근 활성이 큰 것으로 나타났고, 보장구 착용 시 근 활성과 피로도가 줄어드는 경향을 나타냈다. 특히 전경골근과 장비골근의 근육활성 감소와 피로도 감소가 통계적으로 유의한 차이를 나타냈다. 결과적으로 과회내족은 장시간 행군 시 발보장구 착용이 피로도 감소에 효과적이며 이는 잠재적인 하지 근골격계 상해 예방에 도움이 될 것으로 사료된다.

• 한국운동역학회지
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• 제17권4호
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• pp.191-200
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• 2007

The purpose of this study was to analyze the foot-pressure distribution of trekking boots for assessing their functionality. Subjects participated in this study included 10 university male students who had no injury experience in lower limbs and a normal gait pattern. The size of all subjects was 270mm. Five models of trekking boots, most popular in Korea (A, B, C, D & E company), were selected for the test. Using the PEDAR-X system and PEDAR-X insoles, 5 different walking stages were analyzed for the foot-pressure distribution: (a) straight gait; (b) $45^{\circ}$ turn gait; (c) $25^{\circ}$ uphill gait; and (d) $25^{\circ}$ downhill gait. Results of the foot-pressure distribution and functionality on each stage were as follow; 1. Straight gait - In case of Max ground reaction force, mean plantar pressure and Max plantar pressure, there was not a distinct tendency; however, products manufactured by E and A company showed relatively lower pressure distribution. 2. $45^{\circ}$ turn gait - In Max ground reaction force, mean plantar pressure and Max plantar pressure, there wasn't a distinct tendency; however, products manufactured by E and A company showed relatively lower pressure distribution. Results also revealed that the products manufactured by E and A company were superior to those by other companies in terms of functionality. 3. $25^{\circ}$ uphill gait - In Max ground reaction force, mean plantar pressure and Max plantar pressure, there wasn't a distinct tendency; however, products manufactured by E and C company showed relatively lower pressure distribution. Results also revealed that the products manufactured by E and C company were superior to those by other companies in terms of functionality. 4. $25^{\circ}$ downhill gait - In Max ground reaction force, Mean plantar pressure and Max plantar pressure, there wasn't a distinct tendency; however, products manufactured by E company showed relatively lower pressure distribution. Results also revealed that the products manufactured by E company were superior to those by other companies in terms of functionality. Overall, five pairs of trekking shoes selected in this study showed the excellent performance in several conditions. The findings above may provide us with the important criteria for choosing trekking boots.

• 한국운동역학회지
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• 제26권1호
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• pp.11-20
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• 2016

Objective: This study aimed to compare biomechanical data between elite and beginner cyclists during cycle pedaling by performing a comparative analysis and to provide quantitative data for both pedaling performance enhancement and injury prevention. Methods: The subjects of this study included 5 elite cyclists (age: $18{\pm}0years$, body mass: $64.8{\pm}9.52kg$, height: $173.0{\pm}4.80cm$) and 5 amateur cyclists (age: $20{\pm}0years$, mass: $66.6{\pm}2.36kg$, height: $175.6{\pm}1.95cm$). The subjects pedaled on a stationary bicycle mounted on rollers of the same gear (front: 50 T and rear: 17 T = 2.94) and cadence of 90. The saddle height was adjusted to fit the body of each subject, and all the subjects wore shoes with cleats. In order to obtain kinematic data, 4 cameras (GR-HD1KR, JVC, Japan) were installed and set at 60 frames/sec. An electromyography (EMG) system (Telemyo 2400T, Noraxon, USA) was used to measure muscle activation. Eight sets of data from both the left and right lower extremities were obtained from 4 muscles (vastus medialis oblique [VMO], vastus lateralis oblique [VLO], and semitendinosus [Semitend], and lateral gastrocnemius [Gastro]) bilaterally by using a sampling frequency of 1,500 Hz. Five sets of events ($0^{\circ}$, $90^{\circ}$, $180^{\circ}$, $270^{\circ}$, and $360^{\circ}$) and 4 phases (P1, P2, P3, and P4) were set up for the data analysis. Imaging data were analyzed for kinematic factors by using the Kwon3D XP computer software (Visol, Korea). MyoResearch XP Master Edition (Noraxon) was used for filtering and processing EMG signals. Results: The angular velocity at $360^{\circ}$ from the feet was higher in the amateur cyclists, but accelerations at $90^{\circ}$ and $180^{\circ}$ were higher in the elite cyclists. The amateur cyclists had greater joint angles at $270^{\circ}$ from the ankle and wider knee joint distance at $0^{\circ}$, $180^{\circ}$, and $360^{\circ}$ than the elite cyclists. The EMG measurements showed significant differences between P2 and P4 from both the right VLO and Semitend. Conclusion: This study showed that lower body movements appeared to be different according to the level of cycle pedaling experience. This finding may be used to improve pedaling performance and prevent injuries among cyclists.