ISBS (International Society of Biomechanics in Sports): Conference Proceedings Archive
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EFFECT OF DIFFERENT CYCLING CONDITIONS ON SAGITALL AND FRONTAL LOWER LIMB KINEMATICS OF COMPETITIVE AND RECREATIONAL CYCLISTS
Get PDFThe aim of the current study was to compare sagittal and frontal hip, knee and ankle joint kinematics between competitive and recreational road cyclists across different workloads and pedalling cadences. Five competitive and five recreational healthy male road cyclists performed four conditions (85 rpm and 95 rpm at 200 W and 65 rpm and 75 rpm at 230 W) in random order to cover a variety cadences and workloads used during competition or training (plane, slight hill, medium hill and steep hill). Lower limb kinematic data were collected with nine infrared cameras. T-test and effect size statistics established significant differences in the power phase (0-180") of the crank cycle for knee abduction, knee extension and hip adduction between the two groups. Increase in hip and knee frontal plane motion indicated altered pedalling technique for recreational cyclists
BALL VELOCITY AND ELBOW LOADING IN FASTBALL PITCHING
Get PDFAmong baseball players, the pitchers are the most prone to injuries. These injuries occur mainly at the medial part of the elbow and at the shoulder. It is widely accepted that high joint loading are linked to overuse injury for repetitive motion. At maximal exo-rotation (MER), the elbow maximal abduction moment is predominantly counteracted by the ulnar collateral ligament and causes great stress on this structure. The aim of this study is to investigate the relationship between the elbow maximal abduction moment, ball velocity and technique. Thirteen elite pitchers participated in this study. Elbow maximal abduction moment was computed by an inverse dynamics method. Results indicate that the mean maximal abduction moment of the forearm on the upper arm was 41+-9Nm and can be reduced without hampering ball velocity by lowering the elbow flexion angle at MER
A STUDY OF FLUID FORCES ACTING ON A FOOT DURING EGGBEATER KICKS OF WATER POLO PLAYERS
No full textThe purpose of this study was to estimate fluid forces acting on a foot during eggbeater kicks of water polo players by the pressure-distribution-measuring method. Six male water polo players performed eggbeater kicks. Four pairs of pressure sensors were attached to the dominant foot to measure pressure distribution. Fluid-force vectors were calculated. The eggbeater kick cycles were divided into three phases (i.e. out-, in- and upkick phase) based on the knee joint angle and the displacement of the ankle. Maximum values and mean values of the propulsive component of fluid forces were 165.4 * 24.6 N and 38.2 * 4.6 N (mean i SD). Moreover, it was established that a swimmer mainly produces propulsive forces during out-kick and in-kick phases
THREE-DIMENSIONAL MOTION ANALYSIS OF THE "TENKAN9\u27-TECHNIQUE IN AIKIDO
Get PDFAikido is a Japanese martial art established by Morihei Ueshiba (1883-1969). A major characteristic is that there are neither competitions nor is there practice in form of competition. Generally, practice involves an instructor demonstrating a technique, after which it is practiced in pairs. The present study therefore sought to perform a three-dimensional analysis of the "Tenkan" a typical aikido technique, and to clarify the differences and factors related to the techniques for experts, intermediates, and beginners. We discussed the difference of deviation of the center of mass and evaluation of the ground reaction forces
HOW ELITE SWIMMERS CONTROL THEIR HAND PROPULSIVE FORCE AND ARM COORDINATION WITH INCREASING VELOCITY DURING FRONT CRAWL
Get PDFThe purpose of this study was to investigate the change in the intensity and timing of the hand propulsive force by using pressure sensor and motion capture systems as increasing velocity during front crawl swimming. Twelve elite swimmers participated in this study. The swimmers swam three different velocity; i.e. 70%, 80% and 900h of maximal velocity. The propulsive force of both hands were recorded by multiple pressure sensors, and whole body kinematics was measured by using motion capture system. The average propulsive force during the pull and push phase, and thus, total stroke cycle increased as increasing swimming velocity. The non-propulsive phase decreased as increasing swimming velocity. Swimmers increase their swimming velocity with both increasing their hand propulsive force and decreasing their arm non-propulsive duration during a stroke cycle of front crawl swimming
COMPARISON OF GROUND REACTION FORCES IN TWO RUNNING-SPECIFIC PROSTHESES (SPRINTER 1 E90 AND CHEETAH XTREME): A CASE STUDY
Get PDFThe purpose of this study was to describe the difference in ground reaction forces (GRF) between tvm different running-specific prostheses (RSPs) during maximal sprinting in a transfemoral amputee. One male sprinter performed maximal sprinting with two types of RSP (Sprinter 1E90 and Xtreme) on over 40 m runway with 7 force plates located halfway. Sprint velocity was found to be greater in the trials performed with Sprinter 1 E9O than with Xtreme. The peak VGRF, zero fore-aft shear and impulse of the anteriorposterior component of the GRF with PST limb differed among the two RSPs. These results suggest that the participant in this study would show the differences in variables influencing on the sprint velocity between two types of RSPs
EFFECT OF APPROACH SPEED ON SOCCER SHOOTING PERFORMANCE
Get PDFThe purpose of this study was to investigate the effect of different initial conditions (approaching speeds) on soccer shooting performance (indicated by ankle speed at ball impact). Three initial conditions, including standing still, walking and running at self-selected speeds, were adopted for performing kicking. The results showed that the running condition, with the greatest approaching speed, led to the highest ankle speed for generating the fastest ball speed after impact. The current results will be used for building a mathematical model for simulating soccer shooting with various approach speeds
LOWER EXTREMITY JOINT MOMENTS IN ATHLETICS CURVE SPRINTING
Get PDFThe purpose of this study was to identify the effect of curve sprinting on the three dimensional joint kinetics and to specify the leg specific loading and functionality in the curve. Six male sprinters performed three submaximal curved and linear sprints. The findings point up different functionalities of the inner and outer leg. Peak knee and hip adduction moments were about twice as high at the inner leg compared to the outer leg during curve sprinting and compared to linear sprinting. Furthermore significantly higher peak external rotation moments in the knee and hip joints could be found during curve sprinting. In maximal sprinting these additional tasks may compromise propulsive force generation. These findings help to quantify the side specific load and provide information about involved muscles, which is helpful for the training process and injury prevention
EFFECT OF DIFFERENT TIBIA ANGLES TO LOADING OF KNEE DURING SPLIT SQUAT
Get PDFThe aim of this study was to investigate the difference of knee joint force and moment during split squats of different front tibia angles. Twelve healthy male college students performed six repetitions of four different split squat types with a standard additional load of 25% BW added using a barbell. Using 10 camera 3D motion capture system and a force plate to collect data. The peak force and moment of knee flexion (sagittal plane) were calculated by using self-designed MATLAB programs. One-way ANOVA test was undertaken using SPSS 20.0 statistical software. The analysis results of the study indicated that all kinetic parameters of the four types split squats were achieved high significant differences (p less than .000). A better understanding of different loading in specific joints and correct exercise execution during training will help protecting practitioners from sport injury
EFFECT OF IMPACT SURFACE ON EQUESTRIAN FALLS
Get PDFThis study examines the effect of impact surface on head kinematic response and maximum principal strain (MPS) for equestrian falls. A helmeted Hybrid Ill headform was dropped unrestrained onto three impact surfaces (steel, turf and sand) and three locations. Peak resultant linear acceleration, rotational acceleration and duration of the impact events were measured. A finite element brain model was used to calculate MPS. The results revealed that drops onto steel produced higher peak linear acceleration, rotational acceleration and MPS but lower impact durations than drops to turf and sand. However, despite lower MPS values, turf and sand impacts compared to steel impacts still represented a risk of concussion. This suggests that equestrian helmets standards do not properly account for the loading conditions experienced in equestrian accidents