COMPARATIVE ANALYSIS OF THE TAKEOFF IN POLE VAULT AND LONG JUMP BASED ON TIME-CONTINUOUS DATA

A pattern recognition approach based on time-continuous kinematic data was applied to analyze movement patterns of the pole vault and the long jump during takeoff. Altogether, 24 trials of pole vaulters, long jumpers and decathletes were analyzed using a combination of cluster analysis and discriminant analysis methods. Concerning the jumping movement of the legs structural differences between pole vault and long jump patterns as well as individual movement behaviour were identified. The movements of the jumping leg played an important role for the different TO performances

TIME CONTINUOUS VS. TIME DISCRETE ANALYSIS OF THE TAKE OFF TECHNIQUE IN LONG JUMP

Long jump trials of specialist long jumpers, decathlete and sports students were filmed two-dimensional with one high speed camera. Performance during Take-Off (TO) was analyzed based on time continuous data. All trials were compared for similarity and classified by cluster analysis (Schöllhorn, 1999). Additional cluster analyses considered time discrete variables only. For both data sets, no classification according to jumping performance was found. The results indicate that different TO strategies may result in comparable jumping performance. Consequences on the analysis and training of sports techniques are discussed

INT,ERDISCIPlINARY ANALYSIS OF BIOMECHANICAL MOVEMENT PATTERNS AND MENTAL REPRESENTATIONS OF THE VOLLEYBALL SPIKE

An approach for an integrative analysis of biomechanic and psychologic data is presented. Kinematic movement patterns as well as mental representation of the spike of male volleyball players have been studied to analyze structural interrelationships of cognitive and biomechanical measures. A high congruence of the results of cognitive and biomechanical analysis can be stated. Future research will focus on adaptations of mental representation and performance following practical and mental training, respectively

TEMPORAL AND STRUCTURAL CHARACTERISTICS OF DIFFERENT ATTACK TECHNIQUES IN VOLLEYBALL

A process oriented approach was chosen to identify attack techniques in volleyball. Male subjects were filmed with two high speed video cameras while they performed three attack techniques. Subject's movement was described by the time courses of angles and angular velocities of the main joints and analyzed by a procedure including distance measures and cluster analysis. Cluster analysis classified movement pattems of spikes, and top spin shots, by individual while patterns of lobs were mainly grouped by technique criteria. Except for the quick attacker, lobs are identified if only variables are considered that describes the movement of the arm during take off. From a practical view, the results suggest that a defender should focus on the arm of the attacker dUring take off to recognize the attackers intention early

BIOMECHANICAL ANALYSIS OF THE JUMP SMASH OF GERMAN ELITE BADMINTON PLAYERS

The smash is one of the key techniques to gain success in Badminton. For elite athletes, ball velocities up to 68m/s have been reported for the jump smash (Tsai & Chang, 1998). Differences between the jump smash and the smash without jumping where up to 5m/s. In earlier analyses of German badminton players (Kollath, Bochow, & Westermann, 1986), no differences between both techniques according to ball velocities have been reported. Compared to the international elite players, German Badminton players were ranked in midfield or on even lower positions during the last years, but especially for the female athlete increased performance can be stated in recent championships. To analyze the smashing technique of these athletes, jump smashes of female as well as male Badminton players were analyzed

ANALYSIS OF BADMINTON SMASH WITH A MOBILE MEASURE DEVICE BASED ON ACCELEROMETRY

A mobile measure device has been developed to measure acceleration of the upper and lower arm segment as well as of the racket. The system consists of three 2D miniature sensors and a PDA that was used to store and transfer data via WLAN. Accelerometric and kinematic data of Badminton smashs of international and national elite Badminton players were collected. The resultant acceleration of the racket showed high correlation with the ball velocity (r=.897). Differences between international and national players can be observed primarily in the mean values and standard deviation of the racket acceleration as well as in the negative acceleration of the lower arm. It is suggested that an abrupt stopping of the lower arm supports the development of high racket acceleration

INFLUENCE OF CRANK LENGTH ON PEDALLING ECONOMY IN THE ACCELERATION PHASE IN TRACKCYCLING – A SINGLE CASE STUDY

The purpose of this study was to identify different effects of crank-length on cycling performance in track cycling. Two different crank lengths (162,5mm and 170mm) were used in a single-blind and balanced order at a wooden indoor cycling track. Saddle height and the position of the handlebar were kept constant during all trials. The subject was asked to complete 100m with maximum load with every crank length in each test session. To avoid test effects and effects from fatigue, the order of crank length was changed throughout all test sessions. Measured variables were torque (Nm), power output (W), Force (F), Cadence (rpm) and time (s). Results showed that force output stayed constant, while the 170mm condition had advantages in time, torque and power output due to the longer lever arm. Longer distances than 100m were not analysed

ESTIMATION OF THE JUMP HEIGHT FOR THE VOLLEYBALL SPIKE BY A MOBILE IMU UNIT

The maximal jumping height can be considered as a determining factor of spike as well as overall game performance. The purpose of this study was to develop and validate a mobile device based on inertial sensors as an alternative for in-field diagnostics. 23 female and male volleyball players performed 106 spikes with an IMU fixed at each ankle. An OptojumpNextTM system (OJ) served as reference. Interclass correlation analysis computed a coefficient of r=.995. Bland-Altman-plot showed 95% limits of agreement between 2.9cm and -1,2cm. Hence, the mobile IMU device determines jumping height in real competition conditions with an accuracy of approximately ±2cm. We consider this as acceptable for application in volleyball training, e.g., but further effort is necessary to optimize the detection algorithms to achieve higher accuracy

POSSIBILITIES OF IMPLICIT MOTOR LEARNING IN LONG JUMP PE PERFORMANCE INVESTIGATED BIOMECHANICALLY

Introduction: Many investigations, e.g., Hay/Nohara (1990) deal with the biomechanics and movement techniques of the long jump. Therefore we obtained information about the best performance and advice on how to achieve this goal. Two main strategies of motor learning are known in long jump training: The first is feedback training, where the athlete consciously tries to adapt his performance according to the ideal. The second aims at changes in movement patterns by special exercises and arrangements, e.g., takeoff (TO) at a lower position. In this situation, the long jump performance adapts to the situation without the athlete being aware of what he is really doing. Although this strategy is often used in long jump training, especially with novices, even the trainer doesn’t really know what the results of this training are. The aim of our study is to investigate the changes of long jump techniques of preparation for TO and TO under conditions of ‘unconscious’ practice. Methods: Three groups of students, each in one special training situation, practiced long jump performance in four training sessions. An additional group (no training) was taken as the control group. Two-dimensional kinematic data on the last three strides and TO were filmed before (pre-test) and after the training phase (post-test). The subject’s movement was described by the time courses of the main joint angles and angular velocities. The analysis of the time-normalized data followed a combination of several statistical methods according to Schöllhorn (1995). Cluster analysis was used to classify the results. Results: Clustering the trials by means of all variables, the analysis shows a separation by individuals at the most general level which is independent of pre- or posttest. The next step of cluster analysis classifies the long jump trials by pre- and post-test. Further subdivision of variables indicates different clusters following the changes in movement patterns under specific training arrangements. Conclusions: Due to the shortness of the analyzed movement, the results of the cluster analysis give information on implicit motor learning in long jump training under special arrangements. The subdivision of variables allows us to identify which parts of long jump performance are trained by the applied training arrangement. Further investigations are necessary to prove that the identified changes are individual and do not follow a universal ‘ideal technique’ in the long jump. References: Schöllhorn, W.I. (1995). Comparison of biomechanical movement patterns by means of orthogonal reference functions. Biomechanics in Sports XII. Budapest, 20-24. Hay, J.G., Nohara, H. (1990). Techniques Used By Elite Long Jumpers In Preparation For Takeoff. J. Biomechanics 23, 229-239

FATIGUE IMPAIRS KINEMATICS BUT NOT KINETICS OF LANDING AND CUTTING MOVEMENTS IN ELITE YOUTH FEMALE HANDBALL PLAYERS

Lower extremities are the most affected areas of injuries in indoor team handball, especially for female youth player. The mechanics of such injuries are well-known, however little is known about the influence of fatigue injury on risk factors. This study addresses fatigue-induced changes of movements that are associated lower extremity injuries in female youth handball players. Kinematics and kinetic data of 15 elite youth female team handball players were recorded for double- and single-leg landings as well as sidecutting maneuvers before, in the middle of and after a simulated handball specific load protocol. The protocol consisted of exercises typical for handball match activity. RPE was used as measure of fatigability and showed values ranging from 13 to 18 at the end of the treatment. ANOVA revealed fatigue related changes in initial knee flexion angle of the non-dominant leg in all tasks. For the cutting task, significant changes of the initial knee angle of the dominant leg, the initial and maximum hip flexion angle as well as maximum knee flexion angle of the non-dominant leg were observed. Consequently, fatigue players exhibited more extended movement patterns. In summary, the fatiguing protocol caused changes in landing and cutting kinematics of the non-dominant leg predominantly, whereas movement kinetics where not affected