김윤혁 교수

The human cervical spine is a complex structure that is the most frequently injured site among all spinal injuries. Therefore, understanding of the cervical spine injury and dysfunction, and also biomechanical response to external stimuli is important. Finite element (FE) modeling can help researchers to access the internal stresses and strains in the bones, ligaments and soft tissues more realistically, and it has been widely adopted for spine biomechanics research. Although in recent years num

The balanced performance of dominant and non-dominant leg is very important to Taekwondo sparring. The purpose of this study was to investigate whether elite Taekwondo athletes would have balanced biomechanical performance and intra-limb coordination in executing different types of Taekwondo kicks. Twelve athletes(more than 10 year practice experience) participated in this study and performed six basic kicks(i.e., the front, roundhouse, side, back, thrashing, and turning-back kick). Results indi

Degeneration of the intervertebral discs and facet joints is considered a source of pain in the cervical spine. In this study, we developedfinite element models of cervical spines that were healthy or had various extents of degeneration and investigated changes in biomechanicalbehaviors of the cervical spine, such as range of motion (ROM), intradiscal pressure, and facet joint forces. Degenerativechanges associated with mild, moderate, and severe degeneration of the disc and facet joint were des

Joint loading, such as join forces and moments, needs to be investigated as fundamental information for prediction and analysis of skating-related musculoskeletal injuries. However, there is a lack of previous biomechanical studies due to technical difficulties in measuring three-dimensional motion data and ground reaction force data in the ice rink. A wearable motion analysis system with inertial sensors and in-shoe pressure sensors was recently developed. In this study, the knee joint kinemati

With recent advances in data communications and robotic engineering, surgical robots have evolved into telerobotic surgical platforms that permit surgeons to operate on patients from remote locations using robotic instruments. Even so, telesurgical systems need to be improved by considering haptic sense or force feedback. In this study, a laboratory-level telesurgical system with force feedback was developed using industrial robots and commercial haptic systems operating over the Internet. Teles

The main principle of open-wedge high tibial osteotomy (HTO) is to shift the weight-bearing line of the knee joint in order to decompress the degenerated compartment and delay osteoarthritis (OA). In this study, the resultant contact forces on the medial compartment, lateral compartment, and total tibiofemoral joint were analyzed during gait for five OA patients before and after HTO in order to fully understand the effect and mechanism of HTO for the OA knee. The compressive, lateral-medial shea

The hip joint diseases have various kinds of origination, and they have multifarious forms according to the originations. One of the major concerns to plan the surgical operation for the hip diseases is the alternation of biomechanical environment, such as joint force and contact pressure. In this study, we analyzed the biomechanical effects of surgical techniques of the hip joint diseases by finite element analysis. We developed the finite element models of the pre-operative and post-operative

Ligaments assist muscles in stabilizing the spine within physiological ranges of motion by limiting the displacements, but the role of ligaments in spinal loads and muscle force distribution remains unknown. The purpose of this study was to investigate the effect of different stiffness on joint resultant forces and muscle forces in different flexed positions. For this study, five ligament stiffness sets were determined from the literature and applied to a musculoskeletal spine model. The dimensi

Ligatures are used with many types of interspinous process devices to prevent instability in flexion movement by wrapping aroundupper and lower spinous processes. In this study, the effects of the pre-tension by tightening the ligature on the spinous processfracture were investigated using a finite element method. Five different interspinous process devices, Coflex-F®, WallisTM, DiamTM,Viking, and Spear®, were chosen, and implanted after creating a defect consisting of bilateral facetectomy with

The aim of this study was to investigate the alteration of lumbar spine and trunk postures on different load-carrying types and amounts under static loading. Two load-carrying types(unilateral carrying: UC vs. bilateral carrying: BC) and four different loads(0, 5, 10, and 15 kg) were randomly tested in this study. Carrying a heavy bag would affect human body posture, specifically lumbar spine curvature, which is considered as one of sources of back problems. Previous studies have not paid attent

주행 중 인체는 발과 지면 사이의 반복적인 충격력을 경험한다. 충격력은 하지의 부상, 편안함 그리고 주행 능력과 높은 연관성이 있다. 이에 신발 메이커들은 하지의 부상을 줄이고 편안함을 향상시키며 주행 능력을 개선하기 위하여 다양한 특성의 중저를 가진 신발을 개발하여 왔다. 본 연구의 목적은 남녀 주행 시 수직 지면반력 및 착지 각도에 미치는 신발 중저 경도의 영향을 조사하는 것이다. 이를 위하여 전문 주자 남녀 각각 다섯 명이 본 실험에 참여하여 연질, 중질, 경질의 운동화를 순차적으로 신고 동일한 속도로 주행하도록 하였다. 결론적으로 성별과는 무관하게 최대 수직 지면반력, 충격력 정점, 디딤 시간은 신발 중저의 경도의 영향을 주지 못하였다. 하지만 중저가 경질이 될수록 부하 시간은 감소하고 부하율은 증가하였다. 이때 남성 참여자가 중저의 변화에 대하여 큰 차이를 보이지 않은 반면 여성 참여자는 상대적으로 더 민감한 반응을 보였다. 저자들은 본 연구의 결과가 향후 성별에 특화된 신

The purpose of this study was to investigate changes in intersegmental dynamics of the lower limb at the instant of push-off in vertical jumps. Using a mathematical model including dynamic equations, the net joint moment (NET) was decomposed into a muscle moment (MUS), gravitational moment, and interaction moment (INT) in terms of joint acceleration and velocity. Ten subjects performed two submaximal jumps (60% and 80% of maximal height) and one maximal jump. Results showed that the hip and ankl

Instability of the distal radioulnar joint (DRUJ) is a common clinical problem due to a fall on the outstretched hand or unexpected forcible wrist rotations. Although there are many surgical treatments available for DRUJ instabilities, many of injuries can be managed conservatively, such as the wrist-wearing DRUJ stabilizer to provide the stability of the joint. However, there is a lack of research regarding use of the stabilizer on wrist joint biomechanics. In this study, a finite element (FE)

The purpose of the study was to investigate how novice runners adjust their lower extremities in heel-toe running while they wear dress shoes and running shoes. Ten novice male runners repeatedly ran across a force plate at 4 m/s in each type of shoes. Joint kinematics and kinetics, vertical ground reaction force, and utilized coefficient of friction during the stance phase were quantified. The results obtained showed no differences in impact peaks, stance time, stride length and joint kinematic

Recently, commercially available computer-aided surgical robot systems have been introduced to enable surgeons to improve the accuracy of cutting and alignment in total knee arthroplasty (TKA). The minimal invasive surgery (MIS) in the TKA has been increased since MIS can improve the surgical outcomes such as the recovery time and hospital stay by reducing the incision in surgery. However, current surgical robot systems do not provide the MIS TKA capability. In this study, we developed a laborat