• 대한안전경영과학회지
• /
• 제15권4호
• /
• pp.153-160
• /
• 2013

The purpose of this study was to compare biomechanical factors on badminton shoes between anti-slip outsole and non anti-slip outsole. Six subjects participated in this experiment. For three-dimensional analysis, eight cameras (Oqus 3series, Qualisys) were used to acquire raw data, and then the parameters were calculated and analyzed with Visual-3D. In conclusion, the patterns of spent time during side step, and maximum velocities of CoGs were consistent without joint angles of lower extremities in spite of small differences. Those of GRFs, and moment of lower extremities were absolutely consistent. This trend of biomechanical factors was that Y shoe (ante-treatment) was much greater and PS shoe (treatment) was greater than Y shoe (treatment). (That was, Y shoe (ante-treatment) > PS shoe (treatment) >Y shoe (treatment)). The findings of this study showed that anti-slip outsole was effective and brought increasing performance and decreasing injuries. It is suggested that further study of these phenomena will help understand many aspects of human locomotion, including work, performance, fatigue and possible injuries.

• 한국전산유체공학회지
• /
• 제21권1호
• /
• pp.103-109
• /
• 2016

With the rapid increase in the number of patients with cardiopulmonary diseases, more cardiopulmonary circulatory assist devices are also needed. These devices can be employed when heart and/or lung function poorly. Due to the critical role they take, these devices have to be designed optimally from both mechanical and biomechanical aspects. This paper presents the CFD results of a baseline model of a centrifugal blood pump for the ECMO condition. The details of flow characteristics of the baseline model together with the performance curves and the modified index of hemolysis(MIH) are investigated. Then, the geometry of baseline impeller and the volute are modified in order to improve the biomechanical performance and reduce the MIH value. The numerical simulations of two cases represent that when impeller radius and prime volume decrease the MIH value also decreases. In addition, the modified geometry shows more uniform pressure distribution inside the volute. The findings provide valuable information for further modification and improvement of centrifugal blood pumps from both mechanical and biomechanical aspects.

• Journal of Korean Neurosurgical Society
• /
• 제62권4호
• /
• pp.382-388
• /
• 2019

Objective : The primary aim of this investigation was to explore the nature of dura mater biomechanics following the introduction of puncture defect(s). Methods : Twenty-eight dura mater specimens were collected during autopsy from the department of forensic medicine of the authors' institution. Specimens were divided randomly into one of four groups : group I (cranial dura mater; n=7), group II (cranial dura mater with one puncture defect; n=7); group III (cranial dura mater with two puncture defects; n=7), and group IV (cranial dura mater with three puncture defects; n=7). Results : The mean${\pm}$standard deviation tensile strengths of the dura mater were $8.35{\pm}3.16$, $8.22{\pm}3.32$, $7.13{\pm}1.77$, and $6.94{\pm}1.93MPa$ for groups I, II, III, and IV, respectively. There was no statistical difference between all groups. A single, two or more punctures of the dura mater using a 20-gauge Quincke needle did not affect cranial dura tensile strength. Conclusion : This biomechanical study may contribute to the future development of artificial dura mater substitutes and medical needles that have a lower negative impact on the biomechanical properties of dura mater.

• The Journal of Korean Physical Therapy
• /
• 제30권1호
• /
• pp.14-22
• /
• 2018

Purpose: This study examined the effects of the lower limb alignment on the pelvis, hip, and knee kinematics in people with genu varum during stair walking. Methods: Forty subjects were enrolled in this study. People who had intercondylar distance ${\geq}4cm$ were classified in the genu varum group, and people who had intercondylar distance <4cm and intermalleolar distance <4cm were placed in the control group. 3D motion analysis was used to collect the pelvis, hip, and knee kinematic data while subjects were walking stairs with three steps. Results: During stair ascent, the genu varum group had decreased pelvic lateral tilt and hip adduction at the early stance phase and decreased pelvic lateral tilt at the swing phase compared to the control group. At the same time, they had decreased minimal hip adduction ROM at the early stance and decreased maximum pelvic lateral tilt ROM and minimum hip rotation ROM at the swing phase. During stair descent, the genu varum group had decreased pelvic lateral tilt at the early stance and decreased pelvic lateral tilt and pelvic rotation at the swing phase. In addition, they had decreased pelvic frontal ROM during single limb support and increased knee sagittal ROM during the whole gait cycle. Conclusion: This study suggests that a genu varum deformity could affect the pelvis, hip and knee kinematics. In addition, the biomechanical risk factors that could result in the articular impairments by the excessive loads from lower limb malalignment were identified.

• 대한정형외과학회지
• /
• 제54권5호
• /
• pp.377-383
• /
• 2019

고관절의 생역학은 고관절에서 체중이 관절면을 통해 전달되는 역학적인 원리를 이해하고 탐구하는 학문이다. 이러한 기초 과학 지식은 퇴행성 관절의 병리와 고관절 치환술 등 다양한 분야에 적용될 수 있다. 특히 고관절의 생역학에 대한 이해를 통해 인공 고관절 치환물의 재료와 설계 및 고정과 관련된 고관절 치환술 분야의 발전을 이루어 왔으며, 수술 방법의 선택, 치환물의 선택 및 위치 등 다양한 부분에 적용될 수 있다. 더욱이 환자의 보다 나은 임상 결과를 얻기 위해서는 고관절의 생역학을 잘 이해하는 것이 필수적이다. 따라서 여기서는 고관절의 생역학을 접근하는 데 필요한 기본적인 지식과 정상 고관절 및 인공 고관절의 생역학적 특성을 알아보고자 한다.

• Korea-Australia Rheology Journal
• /
• 제17권2호
• /
• pp.47-62
• /
• 2005

The present study deals with a mathematical model describing the dynamic response of heat and mass transfer in blood flow through bifurcated arteries under stenotic condition. The geometry of the bifurcated arterial segment possessing constrictions in both the parent and the daughter arterial lumen frequently appearing in the diseased arteries causing malfunction of the cardiovascular system, is formulated mathematically with the introduction of the suitable curvatures at the lateral junction and the flow divider. The blood flowing through the artery is treated to be Newtonian. The nonlinear unsteady flow phenomena is governed by the Navier-Stokes equations while those of heat and mass transfer are controlled by the heat conduction and the convection-diffusion equations respectively. All these equations together with the appropriate boundary conditions describing the present biomechanical problem following the radial coordinate transformation are solved numerically by adopting finite difference technique. The respective profiles of the flow field, the temperature and the concentration and their distributions as well are obtained. The influences of the stenosis, the arterial wall motion and the unsteady behaviour of the system in terms of the heat and mass transfer on the blood stream in the entire arterial segment are high­lighted through several plots presented at the end of the paper in order to illustrate the applicability of the present model under study.

• Journal of Trauma and Injury
• /
• 제37권1호
• /
• pp.1-5
• /
• 2024

The aim of this paper was to review the biomechanics of knife injuries, including those that occur during stabbing rampages. In knife stab attacks, axial force and energy were found to be 1,885 N and 69 J, respectively. The mean velocity of a stabbing motion has been reported to range from 5 to 10 m/sec, with knife motions occurring between 0.62 and 1.07 seconds. This speed appears to surpass the defensive capabilities of unarmed, ordinarily trained law enforcement officers. Therefore, it is advisable to maintain a minimum distance of more than an arm's length from an individual visibly armed with a knife. In training for knife defense, particularly in preparation for close-quarter knife attacks, this timing should be kept in mind. Self-inflicted stab wounds exhibited a higher proportion of wounds to the neck and abdomen than assault wounds. Injuries from assault wounds presented a higher Injury Severity Score, but more procedures were performed on self-inflicted stab wounds. Wound characteristics are not different between nonsuicidal self-injury and suicidal self-wrist cutting injuries. Consequently, trauma surgeons cannot determine a patient's suicidal intent based solely on the characteristics of the wound. In Korea, percent of usage of lethal weapon is increasing. In violence as well as murders, the most frequently used weapon is knife. In the crimes using knife, 4.8% of victims are killed. Therefore, the provision of prehospital care by an emergency medical technician is crucial.

• Physical Therapy Rehabilitation Science
• /
• 제9권1호
• /
• pp.36-42
• /
• 2020

Objective: Many caregivers often carry infants using baby carriers until they are approximately 36 months old. The purpose of this study was to compare the muscular activity of the trunk and lower leg muscles during trunk flexion-extension movements in correspondence to various wearing methods of a baby carrier blanket. Design: Cross-sectional study. Methods: Sixteen healthy adult women were to wear baby carrier blankets in five different ways in terms of direction and height, followed by flexion-extension of the trunk. Erector spinae (ES), rectus abdominis, rectus femoris (RF), biceps femoris (BF) muscle activities and triaxial acceleration of trunk were investigated. Results: The front-wearing method of the baby carrier blanket increased the muscular activity of the ES muscle, and wearing the baby carrier blanket at waist height in the same direction was significantly higher than wearing it at pelvic height (p<0.05). As the angle of flexion increased during trunk flexion-extension, the muscle activity of the ES, BF, and the RF increased. There was a greater increase in muscle activity of the ES and the BF during extension compared to flexion (p<0.05). Conclusions: If it is difficult to wear a baby carrier blanket due to lumbar pain, it is recommended to lower the wearing height of the baby carrier to the pelvic level so that the external load can be transferred to the lower extremity. In addition, it appears to be necessary to hold the baby and distribute the load onto the waist through proper body control when performing flexion-extension movements of the trunk. More objective and scientific research that includes various daily tasks and evaluation methods are needed.

• Clinics in Shoulder and Elbow
• /
• 제21권3호
• /
• pp.151-157
• /
• 2018

Background: Nonunion of lateral humeral condyle fracture causes cubitus valgus deformity. Although corrective osteotomy or osteosynthesis can be considered, there are controversies regarding its treatment. To evaluate elbow joint biomechanics in non-united lateral humeral condyle fractures, we analyzed the motion of elbow joint and pseudo-joint via in vivo three-dimensional (3D) kinematics, using 3D images obtained by computed tomography (CT) scan. Methods: Eight non-united lateral humeral condyle fractures with cubitus valgus and 8 normal elbows were evaluated in this study. CT scan was performed at 3 different elbow positions (full flexion, $90^{\circ}$ flexion and full extension). With bone surface model, 3D elbow motion was reconstructed. We calculated the axis of rotation in both the normal and non-united joints, as well as the rotational movement of the ulno-humeral joint and pseudo-joint of non-united lateral condyle in 3D space from full extension to full flexion. Results: Ulno-humeral joint moved to the varus on the coronal plane during flexion, $25.45^{\circ}$ in the non-united cubitus valgus group and $-2.03^{\circ}$ in normal group, with statistically significant difference. Moreover, it moved to rotate externally on the axial plane $-26.75^{\circ}$ in the non-united cubitus valgus group and $-3.09^{\circ}$ in the normal group, with statistical significance. Movement of the pseudo-joint of fragment of lateral condyle showed irregular pattern. Conclusions: The non-united cubitus valgus group moved to the varus with external rotation during elbow flexion. The pseudo-joint showed a diverse and irregular motion. In vivo 3D motion analysis for the non-united cubitus valgus could be helpful to evaluate its kinematics.