• PNF and Movement
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• 제19권2호
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• pp.153-162
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• 2021

Purpose: The purpose of this study was to investigate the difference in the dynamic balance and leg muscle activity of adults in their 20s with or without shoes. Methods: In this study, seven male and 11 female university students in their 20s were randomized to determine the order of being with or without shoes, and the dominant foot was supported on the central platform of dynamic balance according to the order procedure. Using the opposite foot, the distance of leg stretching in the anterior, posterior medial, and posterior lateral directions and the muscle activity of the supporting leg were measured. Muscle activity measurement sites were attached to the dominant vastus medialis oblique muscle, vastus lateral oblique muscle, tibialis anterior muscle, peroneus longus muscle, and lateral gastrocnemius muscle. Results: As a result of this study, the distance of leg stretching was significantly increased in the anterior, posterior medial, and posterior lateral directions when barefoot rather than when wearing shoes (p < 0.05). The muscle activity of the vastus medial and lateral oblique muscles was significantly increased in all three directions when barefoot rather than when wearing shoes (p < 0.05). The muscle activity of the tibialis anterior was significantly increased in the anterior direction when barefoot (p < 0.05), the peroneus longus muscle was significantly increased when it was barefoot in the posterior medial direction (p < 0.05), and the lateral gastrocnemius muscle activity significantly increased when barefoot in the posterior direction (p < 0.05). Conclusion: The movement of the legs is freed when barefoot as compared to when wearing shoes, and being barefoot can effectively activate muscle activity and improve balance ability.

• 한국수학교육학회지시리즈D:수학교육연구
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• 제13권3호
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• pp.217-233
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• 2009

The purpose of this study is to describe how dynamic geometry systems can be useful in proof activity; teaching sequences based on the use of dynamic geometry systems and to analyze the possible roles of dynamic geometry systems in both teaching and learning of proof. And also dynamic geometry environments can generate powerful interplay between empirical explorations and formal proofs. The point of this study was to show that how using dynamic geometry software can provide an opportunity to link between empirical and deductive reasoning, and how such software can be utilized to gain insight into a deductive argument.

• 한국통신학회논문지
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• 제22권6호
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• pp.1302-1310
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• 1997

In this paper, we propose a dynamic code allocation strategy using voice activity detection and evaluate the performance of a dynamic code allocation strategy using voice activeity detection in DS-CDMA system. Proposed method allocates code to mobile terminal according to the residual capacity computed by SIR in the base station. In hot spot traffic loading cell, we find that the performance of proposed method is better than that of a fixed code assignment strategy using voice activity detection. Also, we find that the proposed method provide much improvement in blocking probability against the dynamic code assignment strategy withoug voice activity detection.

• 대한물리의학회지
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• 제13권3호
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• pp.27-37
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• 2018

PURPOSE: The purpose of this study was to investigate and evaluate muscle activity and foot pressure during gait, and isokinetic strength and balance in persons with functional ankle instability (FAI). METHODS: Nine healthy subjects (CON, n=9) without FAI and 11 patients (FAI, n=11) with FAI participated in the study after having been screened with an ankle instability instrument and a balance error scoring system. In addition, FAI was classified as non-involved (FAI-N) or involved (FAI-I), and CON was classified as dominant or non-dominant. All subjects were evaluated for isokinetic strength (plantar flexion, dorsiflexion, inversion and eversion of $30^{\circ}/sec$ and $60^{\circ}/sec$), balance (static and dynamic), muscle activity (tibialis anterior, peroneus longus and gastrocnemius) and foot pressure (static and dynamic) during gait. RESULTS: Results showed that plantar flexion (p<.05), dorsiflexion (p<.05), inversion (p<.01) and eversion (p<.00) of $60^{\circ}/sec$ were significantly decreased in FAI-I compared to those in FAI-N and CON. C 90 of static balance with eyes open (p<.01) and closed (p<.00) were significantly increased in FAI compared to those in CON. Forward position of dynamic balance (p<.01) was significantly decreased in FAI compared to that in CON. Gastrocnemius and peroneus longus of dynamic muscle activity (p<.01), left and right weight distribution of static foot pressure (p<.00) and pressure distribution of dynamic foot pressure (p<.00) were significantly decreased in FAI-I compared to those in FAI-N. CONCLUSION: We demonstrated that ankle strength, balance, muscle activity and foot pressure were significantly correlated with FAI.

• PNF and Movement
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• 제21권3호
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• pp.291-298
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• 2023

Purpose: This study aimed to suggest an effective exercise for treating anterior cruciate ligament (ACL) and hamstring injuries based on the dynamic control ratio (DCR) for the hamstring and quadriceps during eccentric hamstring exercises. Methods: Twenty-four healthy participants participated in this study. The participants performed three eccentric hamstring exercises, including the Nordic exercise, the supine leg curl, and single-leg deadlifts. During the eccentric hamstring exercises, the vastus medialis oblique (VMO), vastus lateralis (VL), biceps femoris (BF), and semitendinosus (ST) were measured using surface electromyography. Results: The DCR was significantly lower during the supine leg curl and single-leg deadlift than during the Nordic exercise (p < 0.05). The activity of the VMO and VL was significantly greater during the supine leg curl than during the Nordic exercise and the single-leg deadlift (p < 0.05). VL activity was significantly higher during the single-leg deadlift than during the Nordic exercise (p < 0.05). ST activity was significantly higher during the supine leg curl and Nordic exercise than during the single-leg deadlift (p < 0.05). BF activity was significantly higher during the supine leg curl than during the Nordic exercise and single-leg deadlift (p < 0.05). Finally, the BF showed significantly higher activity during the Nordic exercise compared to during the single-leg deadlift (p < 0.05). Conclusion: Based on the DCR ratio and quadriceps activity, the supine leg curl should be introduced early in rehabilitation for ACL injuries.

• 대한전기학회논문지:시스템및제어부문D
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• 제51권1호
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• pp.32-38
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• 2002

This paper describes a development of a portable physical activity monitoring system using two accelerometers to quantify physical activity. The system hardware consists of two piezoresistive accelerometers, amplifiers with gain of 30, lowpass filters with cut-off frequency of 15Hz, offset control circuits, one-chip microcontroller and flash memory card. In order to evaluate the performance of the system we acquired 3 channel data at 32 sample/sec from body-fixed accelerometers in chest and right upper leg. And then the acquired data were processed by MatLab on personal computer. We tried to distinguish not only fundamental actions which are steady-state activities such as standing, sitting, and lying but also dynamic activities with walking, up a stairway, down a stairway, and running. Five subjects participated the evaluation process which compare the video data with the measured data. As a result, the activity classification rate of 90.6% on average was obtained. Overall results showed that the steady-state activities could be classified from the low component of 3-axis acceleration signal and dynamic activities could be distinguished from frequency analysis using wavelet transform and FFT. Finally, we could find that this system can be applied to acquire and analyze the static and dynamic physical activity data.

• 한국응용과학기술학회지
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• 제35권3호
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• pp.905-913
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• 2018

본 연구는 필라테스 동작 시 폼롤러의 적용과 움직임에 따른 몸통과 하지의 근활성도 차이를 알아보는 것이 목적이다. 피험자로 남자 8명을 선정하여 필라테스 네발자세, 교각자세, 코어컨트롤 동작을 매트위에서 정적동작, 폼롤러 위에서 정적동작, 폼롤러 위에서 동적동작으로 무선배정하여 1주 간격으로 수행하였다. 각 동작의 수행 시 척추세움근, 배곧은근, 배바깥빗근, 중간볼기근, 넙다리두갈래근과 넙다리곧은근의 근활성도를 측정하여 일원분산분석으로 분석하였다. 유의수준은 ${\alpha}=.05$로 설정하였다. 첫째, 네발기기 동작에서 폼롤러 동적동작에서는 배곧은근, 배바깥빗근, 중간볼기근, 넙다리두갈래근의 근활성도가 높게 나타났으며(p<.001)(p<.05), 폼롤러 정적동작에서는 넙다리곧은근의 근활성도가 높게 나타났다(p<.001). 둘째, 교각자세 동작에서 폼롤러 동적동작에서는 넙다리두갈래근의 근활성도가 높게 나타났다(p<.001). 셋째, 코어컨트롤 동작에서 폼롤러 동적 동작에서는 배곧은근, 척추세움근, 중간볼기근의 근활성도가 높게 나타났으며(p<.001)(p<.01), 정적 동작에서는 배바깥빗근의 근활성도가 높게 나타났다(p<.05). 필라테스 운동시 근활성도를 고려하여 방법과 난이도를 적용하면 더욱더 효과적일 것이라 사료된다.

• 한국엔터테인먼트산업학회논문지
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• 제14권6호
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• pp.191-199
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• 2020

젊은 세대들은 스마트폰, 텔레비전, 컴퓨터 등 다양한 시각 매체들의 발달로 눈을 많이 사용함으로써 눈의 건강도 약화되고 있다. 이에 본 연구에서는 안구운동과 치료적 마사지로 안구근육을 자극하여 눈건강과 동체시력에 미치는 영향을 알아보고자 하였다. 20대의 대학생 38명을 대상으로 대조군(18명)과 실험군(20명)으로 나누고, 실험군은 안구운동과 치료적 마사지를 매일 30분씩, 주 5회, 4주 동안 실시하였다. 눈 피로도, 눈 뜬 상태 유지 시간, 안구표면온도, 동체시력은 연구 전과 4주 후에 측정하였다. 4주 후 눈피로도는 유의하게 감소하였고(p<.05), 눈 뜬 상태 유지 시간은 유의하게 증가하였다(p<.05). 안구표면온도는 유의한 차이가 나타나지 않았고(p>.05), 동체시력은 유의하게 증가하였다(p<.05). 따라서, 눈의 기능 증진과 눈 건강을 위하여 안구운동과 치료적 마사지를 권장한다. 눈 건강을 회복하고 예방하기 위한 연구자료로 활용되길 기대한다.

• 디지털융복합연구
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• 제11권8호
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• pp.265-272
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• 2013

본 연구는 정상 성인들을 대상으로 동적, 정적 스트레칭을 적용하여 점프 높이와 점프동안의 근활성도를 측정하여 비교 분석함으로써 스포츠 활동에서의 스트레칭 방법에 대한 기초 자료를 제공하는데 목적이 있다. 20명의 대상자를 무작위 추출하여 2 group으로 각각 10명씩 나누었다. 각 각 다른 그룹에 동적, 정적 스트레칭을 적용하였다. 스트레칭 적용 전후에 점프 높이와 점프동안의 외측광근과 비복근의 근활성도를 측정하였다. 통계학적 처리는 공분산 분석을 이용하여 실시하였다. 결과는 동적 스트레칭이 정적 스트레칭보다 점프높이(p<.05)와 점프 동안의 외측광근의 근 활성도(p<.05)에서 효과적임을 알 수 있었다. 따라서 강한 근력을 필요로 하는 운동선수들에게 동적스트레칭을 준비운동으로 적용할 필요성이 있을 것으로 생각된다.

• 대한물리치료과학회지
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• 제30권3호
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• pp.59-71
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• 2023

Background: This study was to investigate the effects of coordinative locomotor training(CLT) using elastic bands on pain, dynamic balance, muscle strength, and muscle activity of female college students with patellofemoral pain syndrome(PFPS). Design: Randomized Controlled Trial Methods: Twenty-six female college students with PFPS were assigned randomly to an experimental(n=13) or control(n=13) group. The experimental group performed CLT using an elastic band. The control group performed squat exercises to strengthen muscle strength. The 30-minute inter- vention was applied a total of twelve times, three times a week for four weeks. All subjects measured the pain, the muscle strength, the dynamic balance, and the muscle activity(VL/VM ratio) before and after intervention. A paired t-test was used for the determination of differences before and after treatment, and an independent t-test was used for the determination of differences between treatment groups. Results: As a result of comparison within groups, the experimental group showed significant differences in pain, muscle strength, dynamic balance, and VL/VM ratio after the experiment(p<0.05), and the control group showed significant differences in pain, muscle strength, and dynamic balance after the experiment(p<0.05). In comparison between the two groups, the experimental group showed more significant differences in pain, dynamic balance, and VL/VM ratio than the control group(p<0.05), and the control group showed more significant differences in muscle strength than the experimental group(p<0.05). Conclusion: Based on these results, CLT using elastic bands effectively improved the pain, muscle strength, dynamic balance, and VL/VM ratio of female college students with PFPS.