INSTRUMENTATION AND MEASUREMENT METHODS APPLIED TO BIOMECHANICAL ANALYSIS AND EVALUATION OF POSTURAL STABILITY IN SHOOTING SPORTS

The main problem of sport technique in precision sports consists in maintaining the body segments as stable as possible in position and orientation. Experimental data in shooting sports proved that the posture that shooters adopt is mechanically unstable as consequence of the interactions among the body segments. In this way shooters and archers try to make their posture more consistent and reproducible reducing the variability of their actions during the aiming and shooting. The object of this study is to present the basic consideration respect to biomechanical analysis and evaluation of postural stability in shooting sports. The proposed theoretical model and the designed measurement chain composed of a sonic digitizer, a force plate and an EMG system seems to be an efficient tool in order to describe and evaluate postural stability

3D KINEMATIC ANALYSIS OF THE THREE MAIN STROKES IN PADDLE TENNIS MOTOR PATTERNS

Paddle tennis coaches are lacking of scientific support in order to devise the most effective individual training program of stroke technique. Therefore, 30 kinematics and the temporal structure of the movements of three paddle tennis strokes have been analysed. Specifically, they have been calculated spatial-temporal variables of two successful trials of three main strokes (tray-smash, Hook-smash and Exit-wall drive) performed by a world class player

MULTI-MUSCLE SYNERGIES DURING LIFTING AND LOWERING TASKS: AN UNCONTROLLED MANIFOLD ANALYSIS

In ergonomics, lifting tasks can be categorized according to their risk level of suffering work-related low back disorders (WRLBD). The aim of this study was to investigate whether trunk muscles form synergies that stabilize the time profile of selected performance variables that have been used previously to characterize the risk level for developing WRLBD. At the neuromuscular level, the spatiotemporal pattern of motoneuronal activity was quantified by applying matrix factorization algorithm with Varimax rotation. With this procedure, synergies were quantified using the framework of the UCM hypothesis. The results supported the hypothesis that trunk muscles form synergies to stabilize the time profile of variables that are being also used to characterize the risk of injury

3D KINEMATICS APPLIED TO THE STUDY OF INDIVIDUAL BMX GATE START TECHNIQUE

Even if the BMX modality has been included in the schedule of the Olympic Games since Beijing 2008, there is a lack of scientific studies concerning this sport. According to the opinion of many trainers and experts, the start of the race is very important and both neuromuscular potential and sport technique are very relevant aspects of sport performance. The purpose of this study was to analyze the technique of three top young athletes of BMX during the starting gate in order to obtain relevant information to support their trainer’s decisions

ERGONOMICS AND “USABILITY” APPLIED ON THE TRAINING OF MUSCULAR FORCE QUALITIES

“Usability” is introduced, for the first time, as an ergonomics criterion concerning the development and functional evaluation of the muscular force qualities training programs, based on the use of biomechanics methodology. Thus, the main purpose of the present study is to introduce ergonomics applied to the training as a method to prevent WRMSDs (Work-Related Musculoskeletal Disorders) that cause the high loads and efforts as well as overuse, regarding mechanical work and power. “DynaSoft 2.0” is a 3D Inverse Dynamics package that allows for the evaluation of the developed mechanical loads during the repeated series of exercises in the training of muscular force qualities. “DynaSoft 2.0” makes possible the treatment of data not obtained from “turn-key systems” that could be too expensive, and, the user has the possibility to have by own the control of all analysis processes constructing purposeful anthropometric models

BIOMECHANICAL ANALYSIS TO DETERMINE MUSCLE INTERVENTION

Joint mobility is an advantage to sport technique optimization. The aim of this work was to examine the relationships between hip angular velocity and angular acceleration and the tension level of Rectus Femoris (RF), Vastus Medialis (VM) and Biceps Femoris (BF) muscles during execution of a ballistic stretching exercise. Measurements of body segments’ kinematics were made using a motion capture system (Xsens) synchronized with an EMG capture system (Delsys). Obtained results have shown that a reliable methodology has been developed that allows studying physiologic and functional behavior of biokinematics unity

DEVELOPMENT OF A MEASUREMENT CHAIN TO EVALUATE MUSCULAR INTERVENTION IN ARCHERY PERFORMED BY PHYSICALLY DISABLED

The complexity of the motor activity in archery, and, the participation of physically handicapped persons in highest level competitions, gave rise to the development of a measurement chain that allows to analyze shooting technique recording simultaneously the posture adopted by subjects and the activity of the main involved muscles. The measurement chain consists in an EMG and a synchronized ELGoniometric system. Obtained data and the calculated standard parameters in the time and frequency domain allow to gain insight into the most convenient individual solutions that archers adopt, according to their motor capabilities, and, on the other hand, to clarify the intervention of archers’ main muscular groups. Finally it is possible to establish a real-time feedback loop concerning bow’s strain during the draw phase

BIOMECHANICAL ANALYSIS APPLIED TO THE EVALUATION OF POSTURE IN LAPAROSCOPIC SURGERY

Laparoscopic techniques allow less-invasive treatment of common surgical problems in the field of Sports Medicine and Orthopaedics. Laparoscopic instruments have been reported as being uncomfortable, leading to musculoskeletal disorders (pain, stiffness and numbness) during and after the work, due to the forced posture that surgeons have to adopt for long periods (Berguer, et al. 1999; 2001). These muscular disorders are work related (WRMSDs) because of the remote visualization of the surgical field and the deficient design of the laparoscopic instruments. Even if several studies have been developed to obtain information in this field, there is still lack of research findings concerning the surgical procedures developed in the "real world" of the operating room conditions. The main aim of this study in progress, is to establish objective criteria concerning the design and use of laparoscopic instruments using the Ergonomics methodology. Besides, research findings could support the training process of the surgeons. To this purpose there is a need for developing a feasible methodology to detect the presence of risk factors on the surgeons' health

ANALYSIS OF THE MUSCULAR INTERVENTION IN A BALLISTIC STRECHING EXERCISE BASED ON THE ANGULAR ACCELERATION AND EMG DATA

The aim of stretching exercises is to increase muscle-tendon flexibility which depends on neurogenic (stretch reflex), myogenic (viscoeiasticity of the musculo-tendinous structures) and joint constraints (Taylor et al. 1990; 1997). Among the other common techniques (passive, static and PNF) ballistic stretching is using the momentum of a moving body or a limb to force it beyond its normal range of motion. However, in spite of the exciting concerns of stretching neuromechanics, as well as, the overestimation of the role of connective tissue and the underestimation of the resistance of the muscles to stretch (Hutton, 1992), there is a lack of studies concerning the muscular activity in ballistic stretching. The main purpose of this study was to determine the intervention of the muscles quadriceps femoris (rectus femoris - vastus medialis) and biceps femoris and its relationship with the kinematics of the hip joint during a common ballistic stretching exercise

A MECHANICAL MODEL FOR MEASURING IN THREE DIMENSIONS THE SMALL AMPLITUDE COUPLED MOTION THAT CHARACTERIZES MOTOR PATTERNS IN SHOOTING ACTIVITIES

INTRODUCTION: During the aiming in air rifle shooting from a standing position, the shooter, in order to align his eye with the rifle and the target, adopts a posture characterized by a pronounced extension with simultaneous lateral bend and slight twist of the trunk (coupled motion) with respect to the pelvic girdle. Shooters try to maintain this posture, passing mechanical loads across the passive structures and elements of the locomotor system. However, the viscoelastic properties of muscles disturb the shooter - rifle system introducing small amplitude oscillations that tend to deflect the aiming line from the target. The purpose of this study is to develop and validate a mechanical model for measuring with precision these small amplitude rotational movements of the shooter’s trunk and the rifle. METHODS: The spatial coordinates of nine markers that define three segments on the shooter-rifle system are obtained using sonic digitizing techniques (Gianikellis et al., 1994). Position-time data are smoothed using quintic splines, and orthogonal coordinate frames are assigned to the three segments, namely upper trunk, pelvic girdle and rifle. Then the orientation of each segment with respect to the global system of reference is expressed by the Cardan angles, where the rotation matrix is parameterized in terms of three independent angles, resulting from an ordered sequence of rotations with respect to the three axes of the global system of reference. RESULTS: By means of this method it is possible, for first time, to measure the small rotations that take place in such particular motor activity. In the table the average values of the range of angular movement of the three segments are represented for the concrete case of 60 trials that we studied. The model was validated by simulation procedures, knowing the precision in the coordinates data. So the random errors (