• Korean Journal of Applied Biomechanics
• /
• v.16 no.3
• /
• pp.19-31
• /
• 2006

이 연구의 목적은 각 분절의 마커세트와 무릎관절 중심 정의가 3차원 무릎 관절각을 산출하는데 얼마나 민감하게 영향을 미치는지를 연구하였다. 자료수집은 1명을 실험대상자로 하여 두 가지 형태의 각기 다른 분절의 정의와 무릎관절의 중심을 나타내는 반사마커들을 동시에 오른쪽 하지에 부착시켜 실험을 실시하였다. 실험대상자의 달리기동작 중 좌측으로 45도 방향전환동작의 지지기를 분석하였다. 이를 위해서 8대의 고속카메라들을 이용하였고 달리기속도는 4m/$sec{\pm}(10%)$로 통제하였다. 하지분절의 발분절에는 하나의 마커세트를, 정강이와 대퇴분절에는 두 가지의 다른 마커세트들을 부착시켰다. 발분절에는 3개의 마커를 신발의 뒷부분에 부착하였고 정강이분절을 정의하기 위하여 첫 번째 마커세트는 경골을 중심으로 3개의 마커들을 두 번째 마커세트는 비골을 중심으로 3개의 마커를 부착하였다. 대퇴분절의 마커세트를 정의하기 위하여 첫 번째 마커세트에는 대퇴골을 중심으로 3개의 마커를 두 번째 마커세트에는 대퇴근육을 중심으로 3개의 마커들을 부착하였다. 무릎관절중심을 정의하는데 두 가지 다른 정의가 적용되었다. 첫 번째 무릎중심을 무릎의 내측과 외측의 마커들을 통해 두 마커의 중심을 무릎관절의 중심으로 정의하였다. 두 번째 무릎중심정의는 무릎의 외측부분과 슬개골의 중심에 부착된 마커들로부터의 교차점을 무릎관절중심으로 산출하였다. 무릎관절의 각도를 산출하기 위해서 JCS(Joint Coordinate System)의 정의가 적용되었고 연구의 결과는 다음과 같았다. 두 가지의 다른 분절마커세트 사이에서 무릎의 신전(extension)과 굴곡(flexion)은 유사한 형태를 나타냈으며 최대 무릎굴곡(peak knee flexion)각에서 $4.746^{\circ}$의 차이를 나타냈다. 다른 분절마커세트 사이의 회전(rotation)각과 내전(adduction)/외전(abduction)에서는 서로 다른 형태를 나타내었고, 두 마커세트간 최대무릎외측회전(peak knee external rotation)각도에서는 $15.628^{\circ}$의 차이를 나타냈다. 또한, 각 분절마커세트 내에서 두 가지의 다른 무릎관절 중심의 정의가 얼마나 무릎도 산출에 영향을 미치는지를 비교했을 때 무릎의 최대외측회전(peak external rotation)각에서 차이를 나타내었다. 첫 번째 분절마커세트의 무릎관절중심정의의 형태변화에 따라 최대외측회전각은 $0.549^{\circ}$의 차이를 나타냈고, 두 번째 분절마커 세트에서 무릎관절중심정의의 형태변화에 따라 최대외측회전각은 $0.309^{\circ}$의 차이를 나타냈다. 이와 같이 분절을 나타내는 마커세트와 무릎관절중심정의의 형태변화에 따라 무릎간을 계산하는데 있어서 결과가 다르게 산출되었다. 즉, 관절각의 계산이 분절에 부착되는 마커의 정의 혹은 위치에 매우 민감하게 영향을 받았다. 따라서 연구자가 여러 실험대상자들을 대상으로 실험시 마커세트 혹은 마커들을 동일한 위치에 가깝게 부착하는 것이 마커부착으로부터 발생하는 실험오차를 줄일 수 있을 것이다.

• Korean Journal of Applied Biomechanics
• /
• v.18 no.1
• /
• pp.1-10
• /
• 2008

This study analyzed the rear foot angle of the supporting leg and the anatomical rotation angle of the kicking angle in soccer instep kick and drew conclusions as follows. When the supporting leg was landing on the ground, the valgus angle of the ankle joint reached the maximum peak, and plantar flexion was slightly different in the timing of the maximum peak between the two groups. The flexion angle of the rear foot was statistically significantly different between the two groups, and the movement of the crus on the landing of the supporting foot did not show a statistically significant difference between the groups. The crus leaned backward most before the impact, and the side to side gradient of the crus on impact was $22^{\circ}$. The flexion/extension of the hip joint of the kicking leg reached the maximum peak when the supporting foot was landing on the ground, and at the moment, the maximum extension angle of the hip joint was over $30^{\circ}$. The flexion angle of the knee joint of the kicking leg was largest after landing. While the maximum plantar flexion angle and maximum valgus angle of the ankle joint were not significantly different between the two groups, the maximum external rotation angle was significantly different.

• Korean Journal of Applied Biomechanics
• /
• v.18 no.2
• /
• pp.95-104
• /
• 2008

The purpose of this study was to investigate kinematic coordination and control of lower segments in skill process. For the investigation, we examined the difference of resultant linear velocity of segments and angle vs angle graph. Novice subjects were 9 male middle school students who has never been experienced a taekwondo and expert subjects were 7 university taekwondo players. We analyzed kinematic variables of Dollyochagi motion through videographical analysis and the conclusion were as follows. 1. Examining the graph of novice subjects' maximal resultant linear velocity of the thigh, shank, and foot segment, as it gets closer to the end of the training, the maximal resultant linear velocity in each segment increased. Statistical analysis showed the following results; thigh segment caused the increase of speed, using the trunk segment's momentum in the latter term of learning, while the shank segment utilized the momentum of the adjacent proximal segment at the beginning of learning, and the foot segment in the middle of learning. 2. Until the point where the knee joint angle is minimum, as the novice group learn the skill, the flexion of knee and hip joints has changed into the form of coordination pattern in phase. On the other hand, the expert group showed continual coordination pattern in phase that the movement sequences were smooth. From the knee joint maximal flexion to impact timing, all novice and expert groups showed coordination pattern out of phase. 3. From the knee joint maximal flexion to impact timing, the ankle joint was fixed and the knee joint was extended to all the novice stages and expert subjects.

• The Journal of the Korea Contents Association
• /
• v.9 no.12
• /
• pp.364-375
• /
• 2009

The purpose of this study is to offer basic data for the fall prevention by analyzing the kinematic difference between the lower limb joints and the lower extremities in elderly people's walking given the lower-limb resistance exercises. For this, three-dimensional image analysis was carried out by selecting 7 elderly women from over 70s to under 80 years old. To obtain the three-dimensional location coordinates in the lower limb joints and the lower extremities, it shot with 100Hz/s by using MCU(Qualisys, Sweden) camera. The shot image gained raw data on the location coordinates by using QTM(Qualisys, Sweden). As a result of calculating three-dimensional angle by using program of Matlab 6.5, the following conclusions were obtained. Flexion and extension in the thigh and the lower-leg extremities were indicated to be big in motion of flexion after exercising at E5. Foot segment indicated statistical difference while showing eversion at E4. Knee joints showed flexion at E4 after exercising. Ankle joints showed statistical difference while indicating motion in inversion at E3 and in eversion at E4(p<.05).

• The Journal of the Korea Contents Association
• /
• v.11 no.12
• /
• pp.317-325
• /
• 2011

This study aims to develop the stance-control typed 4-bar linkage orthotic knee joint that replace the locked orthotic knee joint for the disabled with poliomyelitis and muscle weakness of lower limb. Unlike the existing stance-control orthotic knee joint, there are no needs of electric power, connecting circuit, bulky compomnets, etc, because this 4-bar linkage orthotic knee joint is controled by geometric locking. To evaluate the 4-bar linkage orthotic knee joint, a subject participated in this study who has been diagnosed with lower limb poliomyelitis and have used locked type orthotic knee joint. In the results of analysis of subject's gait using 3-dimentional motion analysis system, this 4-bar linkage orthotic knee joint provide the stability during stance phase and knee flexion during swing phase.

• Journal of Digital Convergence
• /
• v.13 no.8
• /
• pp.495-502
• /
• 2015

The purpose of this study was to investigating the effect of taping knee by testing the difference on kinetic variables of lower extremity when speed skating athletes jump on one leg. The results were as follows. The height of jumping after taping was higher, but the vertical height was not different according to taping. On take-off(TO), the horizontal and anterior-posterior maximum impulse force were decreased while the vertical maximum impact force was increased after taping. On landing(LD), the anterior-posterior maximum impulse force was decreased but the horizontal and vertical maximum impulse force were increased. TO, the impulse showed low after taping and the impulse dropped largely LD. The knee's moment of extension, eversion were reduced after tapping TO. LD, the flection moment of knee was decreased, but the inversion moment was increased after tapping. This study implies that the knee tapping helps injury prevention and performance enhancement, sports medicine convergence are needed.

• 한국체육학회지인문사회과학편
• /
• v.53 no.2
• /
• pp.531-540
• /
• 2014

The purpose of this study was to investigate the differences between two inflatable kayak by recording performance related variables during the kayak forward stroke motion. A total of 5 elite high school kayak players were recruited to participate while their kinematics and muscle activations were recorded while performing inside their high school swimming pool. Boat velocity, boats swaying angle, the average angular velocity and were used to evaluate the boats performance. The player's trunk rotational range of motion, knee flexion-extension angle range of motion, maximum trunk rotation angle, the knee flexion-extension angular velocity, and the upper and lower limb muscle activations were calculated and analyzed for the player's efficiency evaluation. There were no significantly different variables for the player's kinematics and their muscle activations for the two conditions. The B kayak was significantly faster than the A kaya. In addition there were no significant differences between the remaining variables for the two kayaks. In conclusion, the B kayak was faster than the A kayak, but neither of the kayaks had an influence on the player's performance variables.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.21 no.12
• /
• pp.162-169
• /
• 2020

This study was conducted from November 25 to December 4, 2019, to unmask differences in physical fitness based on the weight class of high school Ssirum elite-players. A total of 28 high school Ssirum elite-players were compared and analyzed by measuring physical factors (muscle strength/power, agility, anaerobic power, aerobic ability, flexibility, and isokinetic muscle function) by weight class. Data were analyzed using SPSS ver. 23.0. One-way ANOVA was used for comparison between groups. There was no difference by weight class in terms of grip strength, sit-ups, sergeant jump, long jump, flexibility, side step, and reaction time. Evaluation of back muscle strength revealed that the group with more than 100 kg had greater strength than lower weight categories, whereas it was lower in the sit-ups, 20 m shuttle run and the relative values anaerobic power. Considering isokinetic muscle function, no difference was observed between the groups of back muscle strength and knee joint. The results of this study indicate that amongst the high school Ssirum elite-players, there is no difference in muscle power, flexibility, agility, and anaerobic average power per body weight, isokinetic trunk strength, and knee flexion strength, when evaluated according to weight class.

• Korean Journal of Applied Biomechanics
• /
• v.19 no.3
• /
• pp.467-479
• /
• 2009

The purpose of this study was to present the quantitative data which riders can utilize teaching field by comparison analysis of kinematics according to skill level of rider during 2 strides rising trot with the JeJu's-Horse. Participated subjects was consisted of total 10 riders(unskilled: n=5, skilled: n=5). The method of experiment & analysis was based on 3D cinematography. Variables were consisted of temporal, linear & angular kinematics by each event & phase. The skilled assigned more ratio of elapsed time in air than support phase, had the less range of motion in up-down direction and more consistent velocity in lateral & forward direction and performed periodic up-down movement with alignment in vertical direction according to elapsing of phases. The skilled more flexed at elbow and extended backwardly according to elapsing of phases, while more flexed forwardly at hip & knee and plantarflexion at ankle. The skilled postured backward extension but the unskilled do forward flexion. That is, It was considered that the unskilled continued more unstable posture than the skilled during 2 strides in rising trot.

• Journal of the Korean Applied Science and Technology
• /
• v.37 no.4
• /
• pp.839-847
• /
• 2020

The purpose of this study was to analyze the effects of ankle flexibility, gender, and Q-angle on the ankle joint injury factors during one leg drop landing. For this study, 16 males(age: 20.19±1.78 years, mass: 69.54±10.12 kg, height: 173.22±4.43 cm) and 16 females(age: 21.05±1.53 years, mass: 61.75±6.97 kg, height: 159.34±4.56 cm) in their 20's majoring in physical education using the right foot as their dominant feet were selected as subjects. First, an independent t-test of joint motion and joint moment according to the experience of ankle injury was conducted to determine the effect of physical characteristics on ankle joint injury during one leg drop landing(α = .05). Second, the variable that showed a significant difference through t-test was set as the dependent variable, and the ankle flexibility, gender difference, and Q-angle were designated as independent variables to use Multiple Linear Regression(α =. 05). As a result of this study, it was found that the group that experienced an ankle joint injury was found to use a landing strategy and technique through adduction of the ankle joint and internal rotation of the knee joint, unlike the group without an injury. It was also confirmed that this movement increases the extension moment of the ankle joint and decreases the extension moment of the hip joint. In particular, it was found that the dorsi flexion flexibility of the ankle affects the ankle and knee landing strategy, and the gender difference affects the ankle extension moment. Therefore, it was confirmed that physical characteristics factors affecting ankle joint injuries during one leg drop landing.