ISBS (International Society of Biomechanics in Sports): Conference Proceedings Archive
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KINEMATIC COMPARISON BETWEEN ATHLETES FROM THE INTERNATIONAL AND THE WORLD TAEKWONDO FEDERATIONS IN THE ROUNDHOUSE KICK
Full text linkTaekwondo (TKD) is a combat sport organized by two main federations: International TKD (ITF) and the World TKD (WTF). The present study analyzed the kinematic differences in roundhouse kick performed by ITF and WTF athletes. Seventeen athletes participated in the study (8 ITF; 9 WTF). DVideo system was used to reconstruct the 3D coordinates of sixteen markers. Pelvis and hips angles and angular velocities were used to compare the groups. The results highlight two kick strategies to hit the target. WTF athletes performed the kick with increased pelvis left rotation while ITF used increased pelvis anteversion, hip flexion and abduction on supporting leg. These differences should be considered for adaptation of rules and training
LOWER EXTREMITY FLEXION ANGLES AND VERTICAL GROUND REACTION FORCE DURING LANDING IN MULTIDIRECTIONS: A PILOT STUDY IN FEMALE ATHLETES
Full text linkSingle-leg jump landing is a complex task. This study investigated lower extremity motion and vertical ground reaction force (GRF) during jump landing between dominant (DL) and non-dominant (NDL) limbs. Five female athletes performed the single leg jump-landing test from a 30 cm height platform in four directions; forward (0°), 30° diagonal, 60° diagonal, and lateral (90°) directions. The findings showed that jump-landing direction significantly influenced hip and knee flexion angles at initial contact phase, hip flexion and ankle dorsiflexion angles, at peak vertical GRF phase, and the peak value of vertical GRF. Female athletes exhibited a trend of using an ankle strategy in multidirections of landing that is similar to stiff landing. An increase of hip and knee flexion should be suggested during landing to increase a soft landing
EFFECT OF FATIGUE ON BASKETBALL THREE POINTS SHOT KINEMATICS
Full text linkThe purpose of this study was to measure the effect of fatigue on basketball shooting kinematics. Young elite players (n=8) were included in the study. Maximal and minimal 3D joint angles, at maximum and minimum centre of mass height were measured with inertial sensors (Moven Biomech, Xsens). Each player performed four 3 points shot (3PS) in dynamic conditions before and after a submaximal exercise (70% of maximal exhausting). This exercise consisted in a repetition of 20-meters sprints with 5 jumps between each sprint. Results showed that fatigue decreased hip joint angle and increased shoulder joint angle when the center of mass was at its lowest point. These biomechanical modifications did not alter the precision of shooting. This study demonstrated that fatigue has small effect on kinematics and precision of the 3PS
COULD LONG-TERM EXERCISE IMPROVE THE OBSTACLE-CROSSING ABILITY OF ELDERLY WOMEN? EFFECTS OF TAI CHI AND AEROBIC DANCE EXERCISES
Full text linkThe purpose of this study was to evaluate the effects of long-term exercises (TaiChi (TC), aerobic dance) on the obstacle-crossing ability of elderly women, as well as to identify whether the exercise could considerably improve stability. Forty-five elderly women include TC, aerobic dance and no exercising groups participated in our study. They walked a short distance to cross the obstacle (30% of leg length). Results showed that long-term exercise had a positive effect on muscle strength and the practitioners used an obstacle-crossing strategy that increasing the force in medial–lateral and anterior-posterior directions of the trailing foot to cross obstacle. The TC strategy was better than aerobic dance in improving balance and increasing the height of the leg during obstacle-crossing
SPRINT START KINETICS: COMPARISON OF AMPUTEE AND NON-AMPUTEE SPRINTERS
Full text linkThe purpose of this study was to observe relationships between reaction forces measured with an instrumented force starting block, start performance (normalized average horizontal block power) and 100 m personal record times in 142 male and female able-bodied sprinters. Further, start kinetics of 7 amputee sprinters and ablebodied sprinters of similar 100 m performance level were compared. Amputee sprinters showed a reduced starting performance, which seems to be related to their lower capacity of creating high peak forces with their rear (affected) legs. In able-bodied athletes, starting performance was related to peak force production in the front and rear blocks, but also to the ability to apply these forces in a horizontal direction. The obtained dataset offers a strong potential for the use in performance diagnostics and feedback training
KINEMATIC COMPARISONS BETWEEN FORWARD AND BACKWARD SKATING IN ICE HOCKEY
Full text linkThe purpose of this study was to examine the kinematics of lower body and trunk between forward and backward skating. Seven male collegiate ice hockey players skated both forward and backward (C-cut) four times each. A standard two-dimensional kinematic analysis was conducted to examine the lower body extremity and trunk at the instants of weight acceptance and propulsion. No significant differences in the joint angles were found at the weight acceptance. At the propulsion, significant differences were found in the joint angles of hip, knee, ankle and trunk between forward and backward skating. Hence, these findings indicate the importance of strengthing lower body joints and trunk, particularly for forward skating. Future studies are warranted to examine the mechanics of forward and backward skating using a 3D analysis
DEVELOPMENT OF A NEW ASSESSMENT METHOD FOR THE REBOUND JUMP TEST
Full text linkWe have proposed a new assessment method using joint kinetics and performance variables in the rebound jump (RJ) test. Twenty-seven male jumpers performed the RJ test. The Quick Motion Analysis System (jointly developed with DKH Inc.) was used to measure joint torque, power, and work of the three lower limb joints in real time, with high precision. High-performance jumpers had high performance values and showed a significantly large amount of joint work in the ankle and hip joints on the RJ test. Comparison of the work of the three lower limb joints confirmed a conflicting relationship between the hip and knee joints and that of the ankles, indicating that this new system is useful for evaluating joint kinetics of the three lower limb joints and may contribute greatly to the assessment of muscle strength and power
SPRINT ACCELERATION MECHANICS
Full text linkSprint acceleration is a key feature in many sports performance. It is a direct determinant of performance and the focus of specific training in track and field events such as the 100- or 200-m, but is also paramount in other sports such as soccer or rugby. In the latter, the acceleration capability is a major physical determinant of performance, especially in decisive offensive and defensive actions. In addition, although the exact moment of occurrence is still debated, sprinting and the acceleration phase in particular are the most frequent tasks involved in hamstring strain injuries. Therefore, a better understanding of the mechanical determinants of sprint acceleration performance could help sport practitioners better design training programs, and likely better manage the complex muscle injury prevention / rehabilitation process. However, due to the very fast motion of the human body induced by maximal acceleration (running speeds of more than 10 m.s-1 are reached within a few seconds), and the necessary field (i.e. specific) measurements, valid scientific methods that provide direct, accurate and specific mechanical data over the course of an entire sprint (start + acceleration phases) are scarce
KINEMATIC AND DYNAMIC COUPLED MEASUREMENTS IN TETHERED FRONT CRAWL SWIMMING
Full text linkForce measurements of athletes in aquatic environments are difficult to perform. Competitive swimming has been confronted with this problem for many years. Tethered swimming is a means used to measure propulsive forces (Martin, Yeater & White, 1981). According to Filho and Denadai (2008), this method is often used to measure the performance level of swimmers and also as a training resource. Its validity has been shown on numerous occasions, notably in its good correlation between swimming velocity, stroke frequency and the measured forces (Yeater, Martin, White & Gilson, 1981; Morouço, Keskinen, Vilas-Boas & Fernandes, 2011). This method has good test–retest reliability (Kjendlie & Thorsvald, 2006), and it provides muscle activity patterns very similar to those displayed in free swimming (Bollens, Annemans, Vaes, & Clarys, 1988). Even if there are questions about the swimming technique used in the tethered swimming compared to the free swimming, this method is important to know the forces created by the stroke technique, especially by the arms. It seems also interesting to measure the forces in the three characteristic paces (long distance, middle distance and sprint). This kinematic and dynamic coupled method is transferable in training pool, and then it could be an everyday tool for swimmers and coaches to measure and to improve the technical swimmers
HYDRODYNAMIC MEASUREMENTS AROUND MOVING PROFILES: FLAPPING FLIGHT, WATER TURBINE, AND OSCILLATING PROFILE
Full text linkIn the field of the fluid mechanics, the team HYDEE (Hydrodynamics and Environmental flow section) of the institute Pprime is involved in the understanding of flows around moving profiles for environmental applications, the maritime transport, the renewable energy production, The research interests cover fundamental aspects of unsteady flows with moving structures, turbulent free-surface flows, environmental flows and mixing through different national and European programs. Fundamental contributions to optical flow measurements include PIV stereoscopy PIV measurement techniques and recently free surface measurement and volumetric measurement techniques have been obtained