LOWER EXTREMITY BIOMECHANICS OF FEMALE COLLEGE SOCCER AND BASKETBALL PLAYERS DURING SIDESTEP CUTTING

The purpose of this study was to investigate the biomechanics of lower extremity between female college soccer and basketball players during a sidestep cutting. Twenty college players participated in this study. Ten Vicon cameras and a Kistler force plate and Visual3D were used to collect side-step cutting and analyze the biomechanical variables. The results indicated soccer players had greater ankle plantar flexion and hip abduction angle at the foot contact. The soccer players also had greater peak knee flexion and internal rotation angle, hip adductor moment, while basketball players had greater peak braking GRF and the peak vertical GRF during cutting. It is concluded that basketball and soccer players demonstrate differences in neuromuscular control patterns during sidestep cutting tasks

THE BENEFITS OF TAI-CHI EXERCISE ON BALANCE CONTROL IN ELDERLY DURING STAIR-TO-FLOOR TRANSITION

The purpose of this study is to investigate the benefits of Tai-Chi Exercise on balance control in elderly during the stair-to-floor transition. Twelve Tai-Chi elder participants and 12 normal healthy elderly were recruited. A Kistler force plate (1000Hz) obtained the COP (center of pressure) data and kinematics calculated from ten Vicon high-speed cameras (250Hz). Results revealed that Tai-Chi group descended at a faster speed and had larger step length. Tai-Chi group also had larger A-P (anteroposterior) COM-COP separation, A-P COP path and faster COP average velocity. The results indicated that long-term Tai-Chi exercise can improve the balance in elderly during the stair-to-floor transition

ROTATION MOVEMENT ANLYSIS IN TAEKWONDO POWER BREAKING MOVEMENT OF 360° JUMP BACK KICK

The purpose of this study was to investigate reaction force of both legs of 360° jump back kick in Tawkwondo. Eight Taekwondo coaches (Height: 175.7±5.7cm; Weight: 75.0±7.9kg; Age: 28.0±4.2years) performed this kick movement to break one inch board. The equipment included ten Vicon cameras (MX13+, 250Hz) and two Kistler force platforms (1000Hz). Kinematic and kinetic data were collected by Nexus software. All variables were calculated by custom written program of MatLab. The results showed that the swing leg provided the push force allowing the axis leg to rotate in rotation phase. The axis leg not only relied on the vertical GRF and impulse obtaining jumping height and moving distance but its joints angle change also balanced the entire body. In conclusion, the interaction of both legs in start-up phase as well as the posture of axis leg during in rotation phase determined the rotation motion of 360° jump back kick in Taekwondo

DYNAMICS OF THE SHOULDER AND ELBOW JOINTS OF THE THROWING ARM DURING ROTATIONAL SHOT PUTTING -CASE STUDY

The purpose of this study was to clarify the dynamical interacting characteristics between the segments of the shot put throwing arm, and to compare the quantitative information between a beginner and an experienced rotational shot putter. The DLT method of 3D cinematography was used. In the throwing motion, compressive force and horizontal adduction torque were mainly exerted at the shoulder joint, while anterior force and flexion torque were mainly exerted at the elbow joint, i.e. the muscle efforts mainly contributed to those forces and torques aforementioned. Subjects' patterns of forces and torques were generally similar, but we found that the timing of anterior, superior forces, external rotation torque, and distractive force were markedly different

BIOMECHANICAL ANALYSIS OF BACK KICKS ATTACK MOVEMENT IN TAEKWONDO

The purpose of this study is to compare three Taekwondo back kicks attack movements. Seven male Taekwondo athletes (age: 21.0 ± 2.0 year old, height: 180.4 ± 4.4cm, weight: 69.1 ± 26.1kg) performed the back kick, jump back kick and 360° jump back kick where the left leg was attack leg. Two Redlake (60Hz) cameras and an accelerometer were used to collect data. The results revealed that the jump back kick’s attack force is greater than in 360° jump back kick. The angular velocity of knee and low trunk of back kick and jump back kick are faster than 360° jump back kick during rotation phase. The 360° jump back kick has a greater attack height and distance when striking the bag. The study suggests back kicking as important skill which the athletes need to practice for improving the kicking ability

THE INTERACTIONS BETWEEN TWO-SEGMENT STRIKING MOTION GENERATED BY PROXIMAL SEGMENT OF UPPER ARM

The purpose of this study was to examine the kinetical interactions between two segments of the upper arm using the forward dynamics derived from Lagrange’s equation of motion, and then clarify the proximal-distal sequence. For the decades, open-linked, multi-segment systems were the important issues to biomechanists. But the more segments have been examined, the more complex the topic has become. Therefore, it is important to examine the effects of joint moment on upper extremities striking motion by simulation of two segments. To facilitate dynamic computation and to simplify the modeling, the upper arm of present study was modeled as a two linked-segment model with upper arm and forearm, in which the forearm and hand were treated as one segment. The summation of results is as follows: When the proximal segment was only given a constant moment (free the distal segment), the whole system displayed a proximal-distal sequence. Furthermore, the distal segment lead to the proximal segment, reaching maximum velocity. The motion presented a periodic fluctuation, and would maintain a straight position indefinitely if the duration of motion were sustained long enough

KINEMATIC ANALYSIS OF VOLLEYBALL JUMP TOPSPIN AND FLOAT SERVE

The purpose of this study is to describe the kinematic characteristics of the volleyball jump topspin and float serve. Thirteen international players performed jump topspin serves and another three players executed jump float serves participated in this study. Two JVC 9800 cameras (120Hz) recorded the players performed jump serves. The results show the jump topspin serve has greater values than the jump float serve on ball velocity, COM velocities at takeoff, jump height, spike height, takeoff to line distance, and horizontal COM displacement. In addition, the mean 1.0cm and 0.7cm of COM spike difference for jump topspin and float serve indicates that elite volleyball players have good timing control during serve action. It is suggested that results from this study can provide useful information for coaches to train volleyball jump topspin and float serve

ELECTROMYOGRAPHIC ANALYSIS OF THE DISCUS STANDING THROW

The purpose of this study was to compare the muscular activation in different discus weights and investigate the sequences and the patterns of the muscular function of the standing throws with discus. The surface EMGs of thirteen muscle groups were measured. The forearm flexor, triceps brachii, posterior deltoid and middle deltoid were highly activated muscle groups in the standing throws. The forearm flexor exerted the highest activation among thirteen muscle groups. The trapezius, pectoralis major, forearm muscle groups, biceps brachium, and anterior deltoid reached the peak EMG activities just before the discus was released. The posterior deltoid, middle deltoid, lower trapezius, and middle trapezius mainly supported the arm and the discus in the early part of the standing throws

EFFECT OF THE KINESIO-TAPING ON FEMALE ATHLETES DURING THE STOP-JUMP TASK POST-FATIGUE

The aim of this study was to investigate the effect of Kinesio taping (KT) by fatigue intervention, on stop-jump task. Eleven female athletes served as subject. Two force plates and ten cameras were synchronized to capture the stop-jump task. We found larger peak hip flexion angular velocity and lower jump height, at touch down after fatigue intervention. When without taping, peak vertical loading rate was increased. After taping, we found delayed time of peak hip flexion angle and peak anterior-posterior force, smaller peak vertical force and vertical impulse within 50 ms at landing phase, along with delayed time of peak vertical force after fatigue. It concluded that KT can decrease the load in landing on knee whether fatigue or not, but has no acute effect on enhancing performance. We recommend that KT be applied on intense exercises with repeated jumping

THE ACUTE EFFECTS OF KNEE ON DYNAMIC HAMSTRING STRETCH DURING SIDE-CUTTING IN FEMALE ATHLETES

The purpose of this study was to investigate the effects of dynamic hamstring stretch on knee joint biomechanical parameters during side-step cutting in female athletes. Methods: Ten participants performed 45-degree side-step cutting for the pre-test and post-test and then dynamic hamstring stretch included single-leg standing with straight leg raise and straight leg hip flexion intervened after pre-test, respectively. Data were collected synchronously by 8 VICON cameras (250 Hz), 1 Kistler force plate (1000 Hz), and 5 Delsys wireless EMG sensors (2000 Hz) during side-step cutting. Results: Participants showed significantly greater hamstrings activation and muscle co-contraction (H/Q ratio) on post-test during deceleration phase at the peak valgus moment. Vertical ground reaction force and knee varus moment decreased significantly on post-test during deceleration phase at the peak varus moment.. Conclusion: Dynamic stretch could increase the activation of the hamstring, and improved buffering impact of the knee joint