KINEMATICS ANALYSIS OF FIVE ANKLE INVERSION LIGAMENTOUS SPRAIN INJURY CASES IN TENNIS

Ankle sprain injury is very common in sport and this study investigated its kinematics. Five injury incidents captured in televised tennis competitions were analysed by a modelbased image-matching motion analysis technique. Results showed a trend of sudden ankle inversion and internal rotation but not plantarflexion. The peak inversion was achieved explosively in a very short time, which is within 0.09-0.17s, after the foot strike. All but one case presented with a slightly inverted ankle joint at foot strike of 10-24 degrees, which should have incited the injury event. We recommend tennis players who perform repetitive sideward cutting motions to attempt to land with a neutral ankle orientation, and to keep their centre of plantar pressure from shifting to the lateral aspect, in order to prevent an ankle inversion sprain injury

IDENTIFICATION OF SIMULATED ANKLE SPRIAN FROM COMMON SPORTS MOTIONS BY FFT AND POLYNOMIAL FITTING ON DORSAL FOOT KINEMATICS DATA

This study presented a method to identify simulated ankle sprain motion from common sporting motions by using motion sensor data. Five subjects performed 100 simulated sprain trials and 245 non-sprain common sporting motion trials in a laboratory. Eight motion sensors were attached to different anatomical landmarks on the right foot to collect 3-D linear acceleration and angular velocity data, which was then processed by fast Fourier transform and polynomial fitting in frequency domain. The coefficients of fitted curve were compared, and the accuracy to identify ankle sprain motion achieved 97.0%. Comparing to a previous method, the current method requires shorter data collection and computation time, and could serve for real time ankle sprain monitoring

THE USE OF MOTION SENSORS AND SUPPORT VECTOR MACHINE FOR CLASSIFYING SIMULATED ANKLE SPRAIN AND NORMAL MOTIONS

Ankle sprain is one of the most common sports injuries. Our research team has developed an intelligent system to prevent the injury, and the system relies on a method to identify an ankle sprain motion. The purpose of this study is to increase the accuracy of Support Vector Machine (SVM) in classifying ankle sprain from normal motions and investigate the feasibility to employ SVM in the intelligent system. Fourteen subjects performed trials of (a) walking, (b) vertical jump, (c) stepping down a stair, and (d) jumping off a stair. Data from a motion sensor at the posterior calcaneus were used and trimmed to 230 (0.4s) and 60 (0.12s) window size, and were transformed from time to frequency domain by discrete Fourier Transform. Motion data from eleven subjects (11 out of 14) were used for training the SVM. A Radial Basis Function kernel function was employed in the SVM. Accuracy was tested on the data from another three subjects, which reached 96.1% and 93.1% for window size 230 and 60 respectively

GROUND REACTION FORCES AND PLANTAR KINETICS OF ROPE SKIPPING IN DIFFERENT SPORT SHOES -A PILOT STUDY

The purpose of this study was to investigate the ground reaction forces and plantar kinetics of different rope skipping skills with different sports shoes. One male elite rope skipper was instructed to skip rope with four skills and with four shoes. The skills included single bounce, double under, triple under and alternative step. The Pedar Mobile system was used to collect plantar pressure information beneath the foot inside the sports shoes. Vertical ground reaction forces (VGRF) of each skip were measured on a force platform. The mean values of each group were calculated for comparison. It was found that the VGRF is greater for triple under (-2.8 times SW on right leg), moderate for double under (-2.5 times SW on right leg), and lower for single bounce (-2.0 times SW on right leg). During, landing, the peak pressure mainly occurred at the metatarsal heads and hallux

MYOELECTRIC STIMULATION ON GLUTEUS MEDIUS OR BICEPS FEMORIS REDUCED KNEE VALGUS TORQUE DURING A FORWARD LANDING TASK

Anterior cruciate ligament injury can be caused by excessive knee valgus torque. This study demonstrated the effect of myoelectric stimulation to the gluteus medius and biceps femoris on the reduction of knee valgus torque. Twelve females performed a forward drop landing task in a biomechanics laboratory. A 130V myoelectric stimulation was delivered to either or both the gluteus medius and biceps femoris through electrodes of different size (38 or 19 cm2) when the subject landed. A motion analysis system was used to obtain the normalized knee valgus torque data. Results showed a significant drop from 15.7 Nm to 11.0-11.4 Nm in stimulating either one muscle with the big electrodes. The technology could be a new option to be implemented as active functional sport apparel for the prevention of sport-related injury induced by knee valgus spraining motion

KINEMATICS AND MYOELECTRIC ANALYSIS OF ANTERIOR CRUCIATE LIGAMENT RECONSTRUCTED KNEE IN DROP LANDING -A PILOT STUDY

This study aimed to investigate the 'lower extremity kinematics and electromyography (EMG) of anterior cruciate ligament (ACL) reconstructed knee during single-leg drop landing. One female elite basketball athlete rehabilitated from ACL reconstruction surgery 33 months prior this study performed five trials of single-leg drop landing from a 300mmhigh platform with the arms crossed over the chest. The motion in sagittal plane was videotaped and was analyzed by a motion analysis system. Foot strike was recognized by a force plate. Synchronized EMG signals from four thigh muscles (vastus medialis, vastus lateralis, medial hamstring, and lateral hamstring) of the landing leg were collected and amplified by an EMG system. The EMG data were trimmed, normalized and filtered. Root mean square (RMS) values of the processed signals were compared. Results showed that thigh muscle activities of ACL-reconstructed leg were lower. Hip joint was more extended before foot strike. Prolonged hip and knee f1exion occurred after foot strike, which delayed the recovery of anatomical position

KINEMATICS ANALYSIS OF ANKLE EVERSION SPRAIN IN SPORTS ONE CASE DURINGTHE 2010 FIFA WORLD CUP

The purpose of this study was to present the 3-dimensional ankle joint kinematics of an eversion ankle sprain case with MBIM motion analysis technique. The results showed that the maximum eversion angle occurred 0.20 seconds after trampled. At that time, the ankle joint was 25° everted, 42° externally rotated, and 15° plantarflexed. The Maximum eversion velocity was 210deg/s. The results from the MBIM technique could contribute to the understanding of the injury mechanism of ankle sprain injury

KINEMATICS AND PHYSIOLOGICAL EFFECT OF A SYNCHRONIZED BIPEDAL “RISE-SIT-GO” CYCLING EXERCISE

This study demonstrated the kinematics and physiological effect of a synchronized bipedal cycling exercise. Fifteen male subjects performed a 30-minutes exercise on a synchronized bipedal stationary bike and a conventional stationary bike at same cycling speed. The performance was evaluated by a metabolic testing system, a subjective rating of perceived exertion, an electromyography system and a motion analysis system, and was compared by paired t-tests. Results showed significant increases in oxygen uptake, energy expenditure, rating of perceived exertion, muscle activity in triceps, biceps, rectus abdominis, left gluteus maximus, left medial gastrocnemius, right tibialis anterior and left tibialis anterior, and range of motion of left hip, left and right knees, shoulders, elbows and wrists. The synchronized bipedal cycling exercise was more physically demanding

SLIP PREVENTION IN WALKING -LOWER EXTREMITY BIOMECHANICS

This study investigated the human slip prevention strategies when walking on slippery surfaces. Fifteen male subjects performed, level walking without slips under sixteen simulated construction site environments. Kinematics, kinetics and electromyography parameters were collected. The slipperiness of the walkway conditions were quantified by the dynamic coefficient of friction (DCOF). Gait changes in slippery condition included prolonged force and pressure exertion in hallux and lateral toes. more ankle plantarflexion moment during 30-50% stance, less knee extension moment during 1030% stance, higher muscle activity at rectus femoris in late stance, and in gastrocnemius in swing phase. These strategies helped achieving walking without slips by reducing the RCOF from 0.188 to 0.092, which was just lower to the dropped available friction (DCOF=0.107)

COMPARISON OF LANDING MANEUVERS BETWEEN SKILLFUL AND UNSKILLFUL FEMALE VOLLEYBALL PLAYERS

This study was to investigate the effect of training to the landing techniques of volleyball spike. Six female subjects were separated into two groups according to their experiences in playing volleyball. Kinematics parameters during landing phase were collected by using three-dimensional motion analysis technique. Pedar insole system with 50 Hz sampling frequency was employed to measure the insole peak force and pressure distribution. Significant differences were found in maximum impact force and peak pressure between the skillful and unskillful group. Skillful group also demonstrated a greater range of motion in the knee, hip and ankle joint respectively. The finding shows that the skillful group, who participated in regular volleyball, demonstrated a greater ability in reducing ground reaction force during landing, thus leading to a protective mechanism in preventing injury