You-Li Chou

National Cheng Kung University | NCKU · Department of BioMedical Engineering

Previous studies have reported that pitchers with glenohumeral internal rotation deficit (GIRD) may increase the risk of shoulder injury. However, limited information is available regarding the specific effects of GIRD in baseball pitching. The purpose of this study was to investigate whether baseball pitchers with GIRD change their pitching mechan...

Background: Previous studies have reported that glenohumeral internal rotation deficit (GIRD) may increase the risk of shoulder injury. However, the effects of GIRD on baseball pitching among pitchers of different age groups are still unclear. Methods: The study participants were 24 high school and 24 university pitchers. For each age group, the...

Falls onto an outstretched hand are the leading cause of upper extremity injury. However, little information is available regarding the effects of fall height and impact strategy on energy absorption ratio between shoulder joint and elbow joint. Twelve male subjects participated in the study. The subjects were asked to perform simulated falls from...

Context Bench-press exercises are among the most common form of training exercise for the upper extremity because they yield a notable improvement in both muscle strength and muscle endurance. The literature contains various investigations into the effects of different bench-press positions on the degree of muscle activation. However, the effects o...

In a forward fall, the majority of the impact energy is absorbed by the elbow joint and shoulder joint. This study examines the effect of the impact strategy on the energy absorption distribution between the two joints during the impact phase of a forward fall. Twenty healthy young male subjects with an average age of 24 years participated in a ser...

This study explores the effect of exercise-induced fatigue on upper extremity stability. The kinematic changes of the upper extremity during bench-press exercise are quantified by measuring the flexion angle and range of motion of the elbow joint, the amplitude of the pitch angle, the amplitude of the yaw angle, and the perturbation frequencies of...

Bench-press exercises are convenient, easily learned, and readily adapted to various levels of difficulty. This study investigates the effect of the fatigue on the maximum possible number of repetitions, the cycle time, myodynamic decline rate and joint force and joint moment in bench-press exercises. The myodynamic decline rate in different isomet...

Push-up is a common exercise used for strengthening the upper extremity muscles. Knowledge of elbow kinematics and kinetics may be helpful in preventing injuries due to push-ups if the elbow shear force can be reduced. Therefore, the purpose of this study was to investigate the effect of different push-up speeds on elbow joint loading. Fourteen hea...

Push-up exercises are commonly performed to strengthen the upper extremity muscles. However, the relationship between the push-up speed and upper extremity fatigue is not well understood. Accordingly, the present study investigated the effect of the push-up speed on the maximum possible number of push-up repetitions until fatigue and the upper-extr...

Falling onto the outstretched hand is the most common cause of upper extremity injury. This study develops an experimental model for evaluating the shoulder load during a simulated forward fall onto one hand with three different forearm axially rotated postures, and examines the shoulder abduction angle and shoulder flexion angle in each case. Fift...

Falling onto the outstretched hand is a major cause of upper extremity injury. The overall objectives of this study were to develop an experimental model for elbow load during a simulated fall onto one-armed arrest using three different forearm axially rotated postures as alternative fall arrest strategies. Additionally, the relationship between th...

Myosin V, a two-headed motor protein, moves along actin filaments toward the positive end. Similar to other molecular motors, myosin V hydrolyzes Adenosine tri-phosphate (ATP) and releases its product to produce movement. This study proposes a multiple-paths model that considers the hydrolysis processes of catalytic sites at the two heads of myosin...

The purpose of this study was to investigate the static and dynamic forces within the joints during push-up loading of the upper extremity. Ten healthy male students volunteered for this study. They were asked to complete six sets of push-ups in five different hand positions. The Expert Vision Motion Analysis System with six CCD cameras, and a Kist...

The bench press is one of the most popular weight training open-kinetic chain exercise (OKCE) for the upper extremity. Reviewing the literature, there is a very little research regarding the biomechanical analysis of the OKCE of the upper extremity. The purpose of this study is to develop an OKCE testing model of the upper extremity by using the 3D...

An experiment has recently been conducted to evaluate and compare the differences in tendon excursions between the flexor digitorum profundus and superficialis using three mobilization techniques. No previous studies deal with the total joint excursions with constant tendon length. The purpose of this study was to investigate the coordinated motion...

This field research was always aimed at clarifying the cosmesis of prosthesis or swing phase of human gait. It is not particularly concerned about the medical problems due to temperature and moisture increase. The generation of heat by metabolic reactions in the enclosed socket is not easily taken away by natural convection and radiation. It would...

From previous researches, studies on the forward fall had focused on the relationship between the joint loading and position of the forearm and elbow. Previous studies also stressed the importance of energy absorption by the shoulder and elbow during the forward fall. However, the effects of different tilting angles on joint loading of the upper ex...

Interface stresses are an important consideration in stump and socket for a prosthetic limb to a person with transtibial amputation. During stance phase of the gait cycle, the prosthetic socket is expected to support and distribute the entire body weight of the patient. Excessive stresses between stump and socket will induce pain, discomfort and br...

There were so many changes in physiological and psychological aspects during pregnancy. Rising from a chair was an important functional activity of daily life. These changes impose postural demands and limit the performance of activities of daily living. The overall goals of this study were to quantify the effects of physiological change due to pre...

The rapid development of gait analysis and its increasing application to pathological gait in children has created an urgent need for normative data. However, research on maturation of gait in children is just in the beginning stage in Taiwan. In order to care for the welfare of children, more data and knowledge in the field are mandatory. The firs...

The elderly wheelchair users frequently encountered the prevalence of pressure sore, also known as decubitus, since they have to be seated in the wheelchair for daily activities. The major cause induced the formation of pressure sore was that the soft tissues were over-stressed. The purpose of this study was to provide the information about interna...

This is the first study of the one-handed pushup, and tries to show the effects of forearm rotations. Previous studies of elbow loading have focused on passive loading and small loads, because data from large loads during active exercise is not easy to obtain. In order to investigate the biomechanical impact of hand position on the elbow and the po...

An Expert Vision motion analysis system with five analog video cameras was used to evaluate the mouth movement during two facial animations (smile and puffy face). Sixteen skin markers were adhered to the face of subject according to the anatomic landmarks to represent the functional movement of the facial muscles. The trajectory of the four or eig...

During pregnancy, a woman changes obviously in body weight, body shape, and endocrine system. Those changes make the posture and gait pattern of the pregnant women different from those of the non-pregnant women. At the same time, activities of daily living become more difficult. But there was still no published paper discussing the posture and gait...

Elbow joint loading was evaluated during a forward fall at various elbow initial flexion angles, in order to determine which is the best elbow initial flexion angles to prevent the elbow injury during a fall. Subjects were asked to perform a forward fall and followed by a push-up motion in different elbow initial flexion angles: 0°, 20°, 40° and un...

The overall objectives are to develop a biomechanical model for a simulated fall with outstretched hand. Cross-sectional study involving young healthy volunteers in a university research laboratory setting. Little is known about the factors which influence fracture risk during a fall on outstretched hand. A group of 11 male subjects volunteered for...

The purpose of this study was to compare the differences of the elbow joint load between two-handed and one-handed pushup exercises. Elbow joint loading was evaluated during two-handed and one-handed pushup exercises using a motion analysis system and a force plate. Results show that in one-handed pushup, large pronation/supination angles were foun...

An algorithm is proposed to recognize the pressure-relief area and pressure-tolerance area on the CAD (computer aided design)model of a residual limb that needs to be modified for the use of making socket. The recognition algorithm includes the basic techniques of image processing, geometric model transformation, and the characteristic distance bet...

This study develops a kinematic/kinetic model to evaluate the effect of different handle angles on wrist loading during lifting task. An imaged-based motion analysis system is used to study the movement pattern, force and moment of the wrist joint among nine different handle angles. Six CCD cameras were used to record 3-D trajectories of limb-mount...

The effect of changing the foot progression angle on the peak knee adduction moment (KAM) during stance was investigated in 48 teenagers. They underwent gait analysis when walking in three different postures: normal walking, intentional in-toeing, and intentional out-toeing. The peak KAM when in-toeing was the highest and was statistically differen...

Elbow joint loading was evaluated during pushup exercises at various forearm rotations. Subjects were asked to perform pushup in various forearm rotations: neutral, 90 degrees internal rotation, and 90 degrees external rotation. Training with pushup exercise is good for the muscles and joints of the upper extremities. However, excessive shear force...

A duplicated mold of the residual limb of an amputee is usually needed to make the socket of prosthesis for the patient. However, traditional means to duplicate a positive mold is time-consuming, patient suffering and intensive manual-efforts required. The study has developed a prototype system that allows a prosthetist to construct the computer-ai...

This study investigates experimentally the velocity of the center of mass with respect to the base of support while subjects step on slippery flooring. The moments of the joints of both legs are also investigated to gain further insights into the source of any correlation found in reacting to slippery perturbation. Twenty-two healthy subjects dress...

This study investigates experimentally the velocity of the center of mass with respect to the base of support while subjects step on slippery flooring. The moments of the joints of both legs are also investigated to gain further insights into the source of any correlation found in reacting to slippery perturbation. Twenty-two healthy subjects dress...

To elucidate the correlating factors and clinical significance of flexible flatfoot (FF) in preschool children of Taiwan, a cross-sectional study was conducted in a research laboratory equipped with a gait analysis facility. Altogether, 377 preschool children (201 boys, 176 girls), ranging in age from 2 to 6 years, were enrolled in this investigati...

Tendons are frequently injured by direct trauma. Tendon adhesions are a common factor compromising the results of tendon repair and to this day represent one of the most challenging problems in hand surgery. Use of controlled motion splints during the early stages of tendon recovery increases tendon gliding. Thus, a variety of controlled motion spl...

The aim of this biomechanical study was to investigate the pressure-time-damage relationship on the cerebral cortex using a rat model. During brain surgery, additional cortical injuries induced by traction have been an important clinical issue. A total of 84 rats underwent a unilateral craniectomy, and conduction by hydrostatic pressure loading thr...

A case of multiple cerebral abscesses caused by actinomyces is reported in a 37 year old male with mucoepidermoid carcinoma of the right lung. In conjunction with penicillin, sulfonamide and erythromycin, the patient underwent stereotactic surgery for aspiration of the brain abscesses under (CT). The bacteria, considered to originate from the right...

This study was performed to determine the biomechanics of chair rising by pregnant women. Relative body joint position and ground reaction forces were measured by a motion analysis system and one force plate. Physiological and psychological changes during pregnancy impose postural demands and limit the performance of daily living activities such as...

Slips and falls often occur in the industrial environments. They are not only caused by environmental hazards but also by some biomechanical factors related to deficient ability of postural control to arrest impending falls. The purpose of this study is to simulate the slip condition in human walking and to find out the possible related factors of...

The aim of this study was to develop an empirical model of parameter-based gait data, based on an artificial neural network and a genetic algorithm, for the assessment of patients after ankle arthrodesis. Ground reaction force vectors were measured by force platforms during level walking. Nine force parameters expressed in percentage of body weight...

Upon encountering a wet or contaminated floor, people often modify their gait and posture to prevent themselves from slipping. This study was conducted to investigate the modification of gait patterns in healthy young adults as they approached and stepped on a slippery floor. Ten females and twelve males were instructed to walk at two different pac...

Upon encountering a wet or contaminated floor, people often modify their gait and posture to prevent themselves from slipping. This study was conducted to investigate the modification of gait patterns in healthy young adults as they approached and stepped on a slippery floor. Ten females and twelve males were instructed to walk at two different pac...

This study scientifically measures the dynamic gait characteristics and energy consumption of 16 male below-knee amputees, eight vascular and eight traumatic, while wearing solid ankle cushion heel (SACH), single axis and multiple axis prosthetic feet via six-camera motion analysis, metabolic measurement cart and heavy-duty treadmill. Subjective re...

Chromobacterium violaceum is frequently found in soil and water in tropical and subtropical regions. The organism rarely causes infection in humans, but is associated with a high mortality rate when it occurs. Septicemia associated with abscess in multiple organs such as the liver, skin, lungs, spleen, lymph nodes, and brain has been reported. We r...

We studied the kinetic characteristics of the knee in patients with spastic diplegia. Twenty three children with spastic diplegia were recruited and had their 46 limbs categorised into the following four groups: jump (n=7), crouch (n=8), recurvatum (n=14) and mild (n=17). In the crouch pattern, the patients usually had a larger and longer lasting i...

The influence of foot progression angle on the ankle joint and the effects on gait patterns and mechanisms in skeletally normal preschool children was investigated. Kinematics and kinetics of the ankle joint were analyzed for preschool children who were skeletally normal but walked with different foot progression angle. The most frequent reasons fo...

Few studies have used motion analysis in the study of facial animation. A facial animation model using an expert vision motion analysis system was developed in this study to quantitatively evaluate absolute movement during five facial animations. Skin markers were adhered to the face of each subject at 16 anatomic landmarks selected to represent th...

The purpose of this study was to employ a computerized motion analysis system to identify the effect of ankle arthrodesis on the three-dimensional kinematic behavior of the rear and fore foot during level walking. A three-segment rigid body model was used to describe the motion of the foot and ankle. The results demonstrated that sagittal plane mot...

Physiological knock-knee (PKK) was categorized by measuring intermalleolar distance (IMD), a clinically simple method, to evaluate the prevalence and correlating factors in 305 preschool children. The prevalence in this cross-sectional study was relatively high, and it was age related (p = 0.002; 64, 44, and 34% for ages 3-4, 4-5, and 5-6 years, re...

In this study, elbow joint during push-up was biomechanically analyzed. It was found that the rotation hand position can effect the kinetics of elbow during the push-up. The peak axial force was decreased from 'normal'. The peak moment exerted on elbow joint was significantly decreased from 'external'.

The long-term wheelchair users, for example the spinal cord injured patients, always have the trouble about the seating pressure sore; and the well-design cushions can offer the wheelchair users to reduce the danger to get the pressure sore. Based on the development of the CAD/CAM system to make custom contoured cushion in our lab, the purpose of t...

The quantitative gait analysis is becoming an important tool for evaluating the outcome of pathological gait, especially for CP children. The purpose of this study is to establish normative data of children and to find the differences in gait patterns between children and young adults. A kinematic analysis system and two forceplates were used to me...

Accurate techniques to evaluate and quantitate gait patterns have been available in clinical applications for the last 20 years. In this study, by employing multiple exposure photography, the walking velocity, stride length, step cadence and joint angle of the lower limbs were recorded for normal young men during the gait cycle. Data were compared...

The purpose of this experiment is to use a low-temperature thermoplastic material (Aquaplast) to make a modified custom-molded cervical orthosis. Sixteen normal young subjects who do not have previous cervical problems are tested in this study. This modified orthosis is applied on these volunteers so that external fixation of the cervical spine can...

The iliac crest is a frequent insertion site for external fixation pins in treating unstable pelvic or acetabular fractures and in iliofemoral distraction for superiorly dislocated hips. The pin-bone interface is critical for the success of treatment, but studies of the iliac crest are lacking. The purpose of this study was to investigate the stren...

The aim of this study was to develop a new algorithm for volume determination by single photon emission computed tomography (SPECT). Different algorithms were evaluated through phantom studies. The results show that the algorithm combining moment-preserving bilevel thresholding and best-fit Laplacian second derivative edge detection can provide the...

Electromyography (EMG) is an essential tool for assessing muscle performance in human locomotion. The aim of this research is to utilize EMG for assessing the habituation processes of normal adults during treadmill walking compared to floor walking. In this research, EMG activity is presented in linear envelope (LE) form to meet physiological meani...

The acceleration period that occurs during isokinetic tests may provide valuable information regarding neuromuscular readiness to produce maximal contraction. The purpose of this study was to collect the normative data of acceleration time during isokinetic knee testing, to calculate the acceleration work (Wacc), and to determine the errors (ERexp,...

To evaluate the potential for the chemical dissolution of gallstones, 480 stones from 214 patients were studied. The stones were obtained via surgery or endoscopically. They were classified into cholesterol-rich mixed stones, brown pigment stones and black stones. The composition of bilirubin and cholesterol was determined by Fourier transformed in...

Intermittent cervical traction with proper angle and force is an effective treatment for cervical syndrome. The goals of therapy are effective traction for the affected segments without further damage to the soft tissue. The purposes of this study were to find the traction angle and force which results in the best therapeutic effect. The effect of...

Quantification of acetabular coverage is important and can be expressed by superimposition of cartilage tracings on the maximum cross-sectional area of the femoral head. A practical Autolisp program on PC AutoCAD has been developed by us to quantify the acetabular coverage through numerical expression of the images of computed tomography. Thirty ad...

By employing the VICON system, segment angular displacement, velocity and acceleration of the lower limbs were achieved from an Above-Knee (A/K) Amputee using a constant friction prosthesis during the swing phase of the gait cycle. By applying computer for data analysis and inputing anthropometric data of the (A/K) Amputee, kinematic trajectory and...

Platelet deposition on fibrin-coated surfaces and release from these adherent platelets were studied in an in vitro flow system. When a mixed suspension of washed platelets and red cells flowed through a fibrin-coated glass tube, only platelets were deposited onto the fibrin-coated surfaces. The density of adhered platelets increased with flow time...

The heat transfer characteristics in a saturated porous medium were also very interesting in many engineering applications. Merkin studied the free convection heat transfer of axisymmetric and two-dimensional bodies. T. S. Cheng obtained the results of heat transfer over a horizontal cylinder and a sphere. The purpose of this note is to extend the...