• 한국운동역학회지
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• 제27권3호
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• pp.197-203
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• 2017

Objective: The purpose of this study was to determine how exercise intensity affects muscle activity and kinematic variables during squat. Method: Fifteen trainers with >5 years of experience were recruited. For the electromyography (EMG) measurements, four surface electrodes were attached to both sides of the lower extremity to monitor the rectus femoris (RF) and biceps femoris. Three digital camcorders were used to obtain three-dimensional kinematics of the body. Each subject performed a squat in different conditions (40% one-repetition maximum [40%1RM], 60%1RM, and 80%1RM). For each trial being analyzed, three critical instants and two phases were identified from the video recording. For each dependent variable, one-way analysis of variance with repeated measures was used to determine whether there were significant differences among the three different conditions (p<.05). When a significant difference was found, post hoc analyses were performed using the contrast procedure. Results: The results showed that the average integrated EMG values of the RF were significantly greater in 80%1RM than in 40%1RM during the extension phase. The temporal parameter was significantly longer in 80%1RM than in 40%1RM and 60%1RM during the extension phase. The joint angle of the knee was significantly greater in 80%1RM than in 40%1RM at flexion. The range of motion of the knee was significantly less in 80%1RM than in 40%1RM and 60%1RM during the flexion phase and the extension phase. The angular velocity was significantly less in 80%1RM than in 40%1RM and 60%1RM during the extension phase. Conclusion: Generally, the increase of muscle strength decreases the pace of motion based on the relation between the strength and speed of muscle. In this study, we also found that the increase of exercise intensity may contribute to the increase of the muscle activity of the RF and the running time in the extension phase during squat motion. We observed that increased exercise intensity may hinder the regulation of the range of motion and joint angle. It is suitable to perform consistent movements while controlling the proper range of motion to maximize the benefit of resistance training.

• 한국컴퓨터그래픽스학회논문지
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• 제24권3호
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• pp.49-59
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• 2018

가상 멀미는 가상 현실의 대표적 부작용 중 하나로 다양한 요소에 의해 영향을 받는다. Field of view (FOV)는 그 중 대표적인 요소 중 하나로, FOV가 줄어들면 가상 멀미는 줄일 수 있으나 임장감 또한 낮아지는 것으로 알려져 왔다. 최근 연구에 따르면 임장감을 유지하면서 가상 멀미를 줄이기 위해 Dynamic FOV Restrictor (Center-fixed FOV Restrictor)가 제안되었으며, 아바타의 속도와 각속도를 반영하여 동적으로 FOV를 제한하였다. 본 연구 그룹에서는 여기에 머리의 회전과 눈의 움직임을 더하여 Eye-tracking Based Dynamic FOV Restrictor (Eye-tracking FOV Restrictor)를 제안하였다. 본 연구는 FOV Restrictor가 없는 조건과, Center-fixed FOV Restrictor조건, Eye-tracking FOV Restrictor조건의 가상 멀미와 임장감을 연구하였다. 본 연구 결과에 따르면 Center-fixed FOV Restrictor조건의 가상 멀미가 다른 두 조건의 가상 멀미 보다 낮은 것을 확인하였고, 세 조건에서 영장감에 차이가 없는 것을 확인하였다. 이러한 가상 멀미 저감 요소 기술에 대한 해석과 한계에 대하여 본 논문에서 논의하였다.

• The Journal of Korean Physical Therapy
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• 제10권1호
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• pp.81-98
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• 1998

Isokinetic evaluation of trunk flexors and trunk extensors was performed at $60^{\circ}/sec\;and\;120^{\circ}/sec$ of angular velocity by using cybex 6000TEF Unit on 31 healthy male white workers and 15 post-operative HILD patients with no significant difference in mean age and mean body weight between two groups, and compared each other. The purpose of this study is to obtain the isokinetic normative strength values and endurance latins for Dunk extensors and trunk flexors, and is to provide a guideline for rehabilitation program of post-operative HILD patients. The collected data were analyzed by ANOVA, Duncan's Nyktuoke Range Test, and Pearson correlation coefficiency in PC-SAS program, The results obtained were as follow ; 1. Post-operative subjects has lower isokinetic values than normal subjects in peak torque, peak torque $\%$ by body weight, total work, total work $\%$ by body weight, average power, average power $\%$ by body weight, TAAE of trunk flexors and trunk extensors, and there are significant differences with statistic value in trunk extensors at $60^{\circ}/sec$ and in trunk flexors and trunk extensors at $120^{\circ}/sec$ between two groups(p<0.05). 2. Pest-ooperative subjects has lower values for angle of peak torque than normal subjects in trunk extensors, and there are significant differences with statistic value at $60^{\circ}/sec$ and $120^{\circ}/sec$ between two groups. 3. Post-operative subjects has higher values for endurance ratios than normal subjects in trunk extensors and flexors, but there are no significant differences with statistic value between two groups. 4. Post-operative subjects has higher values than normal subjects in peak torque ratios, total work ratios, average power ratios of trunk flexors to trunk extensors, and there are significant differences with statistic value between two groups(p<0.01). 5. There is significant positive-correlation with statistic valve between peak torque and height and body weight in normal subjects(p<0.05), but Thjere is significant negative-correlation between peak torque of trunk extensor at $120^{\circ}/sec$ and age (p<0.05). 6. There is significant positive-correlation with statistic value between peak torque of trunk flexors and body weight in post-operative subjects (p<0.05), but There is significant negative-correlation between peak torque of trunk extensor add age (p<0.05). In conclusion, post-operative subjects have greater weakness in trunk musculature than normal subjects, especially there is more significant weakness in trunk extensors than in trunk flexors

• 수산해양기술연구
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• 제25권2호
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• pp.70-74
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• 1989

실험선 제주 402호의 조종성능을 전속전진중 최대타각으로 전타한 때의 선회권측정과 $10^{\circ}$, 20$^{\circ}$, 30$^{\circ}$Z시험에서 산출된 조종성지수를 분석, 검토한 결과를 요약하면 다음과 같다. 1. 선회종거는 우현선회시가 79.1m로 배의 길이의 약 2.6배였으며, 좌현선회시는 81.4m로서 배의 길이의 약 2.7배였다. 또, 선회경은 배의 길이의 약 2.6배로서 우현선회시가 78.3m로서 좌현선회시 80.4m보다 작았다. 2. 선회권시험시 속력저감율은 0.49였으며, 평균선회각속도는 우현선회시가 4.3$^{\circ}$/sec, 좌현선회시는 4$^{\circ}$/sec이었다. 3. Z시험 결과 over shot angle은 우현전타시가 좌현전타시보다 더 컸으며, 좌우타전타시의 평균값은 $10^{\circ}$Z시험시가 10.5$^{\circ}$, 20$^{\circ}$Z시험시가 20.5$^{\circ}$, 30$^{\circ}$Z시험시가 29.5$^{\circ}$로 다소 큰 편이었다. 4. $10^{\circ}$, 20$^{\circ}$, 30$^{\circ}$Z시험에서 K' 및 T'의 값은 각각 0.755, 0.566, 0.481 및 3.468, 1.621, 1.547로서 대체적으로 선회성은 대각도 전타 일수록 나쁘거나, 추종성은 대각도 전타 일 수 록 좋았다.

• 대한족부족관절학회지
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• 제19권4호
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• pp.142-150
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• 2015

Purpose: Restoration of ankle stability through the strengthening exercise of peroneus muscles is considered an important factor for achievement of successful outcomes, in the rehabilitation program following ankle ligament injuries. However, there were few definitive data on normal muscle strength, including eversion power by peroneus muscles. This study was conducted to evaluate the muscle strength of ankle joint measured using an isokinetic dynamometer in normal Koreans. Materials and Methods: Sixty adults (120 ankles) were recruited and divided into three groups (20 in their twenties, 20 in thirties, and 20 in forties). Each group consisted of 10 males and 10 females. The selection criteria were no history of ankle injury and no evidence of instability. The peak torque, total work, and deficit ratio were measured using the Biodex$^{TM}$ (Biodex Medical Systems). Differences in muscle strength by age, gender and dominant versus non-dominant side were analyzed. Results: The peak torque of dorsiflexion was average 31.5 Nm at $30^{\circ}/s$ of angular velocity and 18.8 Nm at $90^{\circ}/s$; average 69.3 Nm ($30^{\circ}/s$) and 42.4 Nm ($90^{\circ}/s$) on plantarflexion; average 19.6 Nm ($30^{\circ}/s$) and 10.8 Nm ($90^{\circ}/s$) on inversion; average 12.9 Nm ($30^{\circ}/s$) and 8.0 Nm ($90^{\circ}/s$) on eversion. The deficit ratio of strength in women was average 61.1% of men on dorsiflexion; average 66.2% on plantarflexion; average 48.5% on inversion; average 55.4% on eversion. The deficit ratio in non-dominant foot was average 88.6% of dominant foot on dorsiflexion; average 90.1% on plantarflexion; average 85.1% on inversion; average 85.6% on eversion. Conclusion: The muscle strength of the ankle joint showed a tendency to weaken with age. There were significant differences in muscle strength by gender and dominancy. Further studies for comparison of patients with ankle instability, a comparison between before and after surgery for instability, the correlation between clinical outcomes and the recovery in muscle strength will be needed.

• 수산해양기술연구
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• 제53권2호
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• pp.177-186
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• 2017

This study is intended to provide navigator with specific information necessary to assist in the avoidance of collision and in operation of ships to evaluate the maneuverability of research vessel Jera. Authors carried out full-scale sea trials for turning test, zig-zag test, and spiral test at actual sea-going condition, which were performed on starboard and port sides with 10-20 rudder angle at service speed of 10 knots. The turning circle was much different at both of the turning of port and starboard which was longer at the starboard than at the port. In the zig-zag test results, the port and starboard was $10^{\circ}$ the first and second overshoot angles were $6.0^{\circ}$, $5.8^{\circ}$ and $6.3^{\circ}$, $7.1^{\circ}$ respectively and the first overshoot angles were $16.4^{\circ}$, $17.6^{\circ}$ when using $20^{\circ}$. Her maneuverability index T and N can be easily determined by using an analogue computer with the data obtained from the zig-zag tests where K is a constant representing the turning ability and T is a constant representing her quick response. In the zig-zag tests under $10^{\circ}$ or $20^{\circ}$ at rudder angle, the value K is 0.149. 0.123 sec- and T is 11.853 and 6.193 sec and angular velocity is $0.937^{\circ}/sec$ and $1.636^{\circ}/sec$. In the spiral test, the loop width was unstable at $+0.51^{\circ}$ and $-1.19^{\circ}$ around the midship of rudder, but the tangent line at $0^{\circ}$ was close to vertical. From the sea trial results, we found that she did comply with the present criterion in the standards of maneuverability of IMO.

• 제어로봇시스템학회논문지
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• 제7권9호
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• pp.723-732
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• 2001

경로 추적의 성능을 향상시키기 위해서 이 논문에서는 광유도식 무인방송차(AGV)의 뉴로퍼지 컨트롤러를 제안한다. 2바퀴 각각 조향 기능이 있는 AGV의 전방과 후방에 센서들이 장작되어 있으며, 그 센서들의 정보를 이용하여 AGV의 경로를 유도하게 된다. 측정된 광센서가 연속적인 데이터가 아니기 때문에 광유도식 AGV 는 쉽게 경로를 이탈하게 되고 경로 추적 성능은 떨어지게 된다. 광센서의정보들은 on/off 신호에 의해 발생되므로 비연속적으로 얻어지게 되고, 동적 오착가 측정되어진다. 센서에 의해 정보를 얻은 후 동적 오차는 좌우측 바퀴의 각 속도를 이용한 데드 레코닝(Dead Reckoning) 방법에 의해 연속적으로 계산되어진다. 여기서, 추정 윤곽 오차는 측정 윤관오차를 윤곽오차의증북(Variation)의 합의로 정의된다. 뉴로퍼지 시스템은 퍼지 제어기와 신경회로망으로 이루어졌다. 추정 윤곽 오차를 줄이기 위해 역전파 (Back-Propagation) 학습에 의해 퍼지 맴버쉽 함수의 계수들은 적응적으로 조정된다. 제안된 기존의 퍼지 제어기와 비교분석된다. 성능 분석을 위해 제안된 제어 이론은 모의 실험에 의해 검증된다.

• 한국산학기술학회논문지
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• 제10권12호
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• pp.3902-3909
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• 2009

본 연구는 비우세 팔굽관절 굽힘근육에 원심성운동을 실시하여, 지연성근육통을 유발시킨 후, 자연치유과 경피신경전기자극치료, 그리고 냉치료의 효과를 조사하는데 그 목적이 있다. 자연치유군과 경피신경전기자극치료군, 그리고 냉치료군의 평가를 위해 팔꿉관절의 운동시에 시상통증척도(VAS), 최대 염력, 실효치 값을 측정하여 평가하였다. 대상자는 신체적 결함이 없는 30명의 성인을 대상으로 하였고, 대상자들은 지연성근육통 유발 후, 3개의 군인 자연치유군, 경피신경전기자극치료군, 냉치료군으로 나누었고, $60^{\circ}$/초의 등속성 각속도에서 최대 근력으로 운동시에 최대 연력과 실효치 값, 그리고 시상통증척도를 측정하여 평가하였다. 1. 시상통증척도는 경피신경전기자극치료군의 치료3일차에서 다른 군과 다른 기간에 비해 가장 낮은 수치를 나타내었고, 통계적으로 유의하였다(p<.05). 2. 최대 염력은 경피신경전기자극치료군의 치료3일차에서 다른 군과 다른 기간에 비해 가장 높은 수치를 나타내었고, 통계적으로 유의하였다(p<.05).3. 실효치 값은 경피신경전기자극치료군의 치료3일차에서 다른 군과 다른 기간에 비해 가장 높은 수치를 나타내었고, 통계적으로 유의하였다(p<.05). 이상의 연구 결과로 보아 경피신경전기자극치료는 지연성근육통에 대하여 자연치유나 냉치료에 비해 더욱 효과적인 치료 방법임을 알수 있다. 그러므로, 지연성근육통을 가진 환자의 치료 시에 경피신경전기자극치료의 적용은 권장되어야 한다.

• 한국산학기술학회논문지
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• 제21권2호
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• pp.167-174
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• 2020

본 연구는 세계적인 선수를 대상으로 남자 기계체조 도마 종목에서 로페즈 기술을 수행했을 때 성공 동작과 실패 동작에 따라 운동학적 차이를 비교 분석하였다. 연구대상은 올림픽 금메달리스트 YHS 선수(나이: 27세, 신장: 160cm, 체중: 53kg중)이였고, 14대의 적외선 고속카메라를 이용하여 도마 동작을 촬영하였다. 원하는 동작 자료획득과 분석을 위해 19mm 반사 마커 26개를 해부학적 주요지점에 부착시켰고, 15개 분절 신체모델을 사용하여 운동학적 변인 계산을 실시하였다. 분석 결과 첫째, 구름판 접촉구간에서 성공 동작의 소요시간이 실패 동작보다 길었으며, 성공 동작은 슬관절의 가동범위를 실패 동작보다 크게 하였다. 둘째, 제1비약에서 성공 동작과 실패 동작의 소요시간은 동일하였다. 성공 동작은 실패 동작보다 짧은 수평이동을 했으며, 높은 수직위치와 도마 착지각을 보였다. 셋째, 도마 접촉구간에서 성공 동작의 소요시간이 실패 동작보다 짧았다. 성공 동작은 도마접촉 순간에 실패 동작보다 좌측 견관절각을 크게 하였다. 넷째, 제2비약에서는 성공 동작의 소요시간이 실패 동작보다 길었으며, 긴 수평이동을 나타냈다. 성공 동작은 도마이륙 순간 우측 견관절각을 크게 하였고, 비틀기 각속도는 빨랐다. 종합하면 YHS 선수가 안정적인 로페즈 기술을 구사하기 위해서는 도마접촉 순간에 높은 자세로 진입하여 도마이륙 순간에서는 우측 견관절각을 크게하여 빠른 비틀기 각속도를 만들어야 한다. 최대높이와 착지 순간에서는 좌·우견관절각을 작게하여 관성모멘트를 줄이고 신체중심을 낮춰야 할 필요가 있다.

• 한국운동역학회지
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• 제14권2호
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• pp.69-83
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• 2004

The purpose of this study is searching for technical merits and demerits of each weight lifting player through qualitative motion analysis system. Moreover, It is also analysis the repeating the establishment of exercise purpose and studying for the effect of the field adaptation. The subject of this study was five male weight lifting players who have been engaged in Korean Delegation Team. The institution of exercise target was made through two times qualitative analysis and the result of studying for the effect of the field adaptation was produced before offering feedback. Moreover, two time analysis added after offering feedback. All analysis was based on 2-D visual analysis. The results of this study are as follows: 1. Maximal barbell moving speed in starting phase was decreased after offering feedback. This result implies advancement of technical skills after offering feedback. 2. From starting posture to 앉아받기, forward and backward moving distance of hip joint was decreased after offering feedback in all subjects. This result represents advancement of technical skills after offering feedback. 3. In terms of pull phase, forward and backward moving distance of hip and shoulder joint was decreased after offering feedback in all subjects. This result represents advancement of technical skills after offering feedback. 4. In terms of pull phase, the difference of horizontal value of coordinates was decreased after offering feedback in all subjects. This result represents advancement of technical skills after offering feedback. 5. In terms of pull phase, the motion range of hip joint was decreased after offering feedback in three of five subjects and this represents advancement of technical skills after offering feedback. However, the rest of them were not variable or narrow decreasing. This result represents that feedback system could not brought tremendous effects. 6. From apex point of barbell to 앉아받기, the difference of barbell height was decreased after offering feedback in three of five subjects and this represents advancement of technical skills after offering feedback. However, the rest of them weren't variable or narrow increasing. This result represents that feedback system could not brought tremendous effects. 7. In terms of last-pull phase, the angular velocity of knee joint was increased after offering feedback in four of five subjects and this represents advancement of technical skills after offering feedback. However, the rest of them, only one subject, decreased. This result represents that feedback system could not brought tremendous effects. 8. In terms of last-pull, the conversional tendency of maximal extension to flextion came out all but simultaneously without offering feedback in four of five subjects. This is well-performed technique. Only one subject, however, could not use power effectively because the fact that his maximal extension came out in serial, from ankle to knee and waist means dispersion of power. In addition to, after offering feedback, only one subject made increasing the maximal extension of knee in last-pull and this result represents advancement of skills after offering feedback. However, the rest of them could not make meaningful development after offering feedback. 9. It might be assumed that searching for technical merits and demerits of each weight lifting player through qualitative motion analysis system could improve player's skill.