OPTIMAL VELOCITY PROFILES FOR VAULT

The aim of this study was to determine which kinematic characteristics may be used as a performance indicator(s) for vault. Over 600 vaults (299 men and 216 Women, see Table 1) were recorded and analyzed using footage of 3 high-speed cameras taken at the 2010 Rotterdam Artistic Gymnastics World Championships. The kinematics were correlated with the judge’s outcome score: type of vault, difficulty and final score. The correlation coefficients between velocity at takeoff and final judges’ scores were r = 0.60 for men and r = 0.52 for women

CONTOUR ANALYSIS, A NOVEL APPROACH IN MOVEMENT SCIENCE

Contour Analysis is a novel way for analyzing movements, which is specifically developed for daily use in high performance sports. The Contour Analysis is part of an automatic video capture and playback system, the CoachCockPit. Parameters like position, velocity and average body angle are obtained and also less straightforward parameters as step length or step frequency or 3D discus trajectory and speed can be investigated with Contour Analysis. The system is designed to operate fully automatic with a minimum of user input. Performance parameters obtained from the Contour Analysis can be used for direct feedback and to monitor progress over longer periods of time. To illustrate this several examples in different sports are discussed. The CoachCockPit is developed with primarily the coach perspective in mind: it does not interfere with daily training

MONITORING TRAINING LOAD OF ELITE TRAMPOLINISTS; FIRST RESULTS; AN AUTOMATIC ANALYSIS SYSTEM FOR DAILY USE

We developed a video-based analysis system to monitor and analyze performance in technical sports, the CoachCockPit. The CoachCockPit captures footage of a performance, stores and presents it instantly. Footage can automatically be analyzed and fed back. We show how daily training activity of trampolinists is monitored and parameters like number of routines, number of jumps per routine, or jump height, can be extracted. Over weeks and month these parameters display trends that provide information about training progress in relation to the aimed-for training results. Overtraining and stress fractures are crucial risk factors in trampoline jumping. The deployment of the CoachCockPit in trampoline jumping will, in the future, help to predict these risk factors at an early stage

Differential regulation of the Wilms' tumor gene, WT1, during differentiation of embryonal carcinoma and embryonic stem cells.

The expression pattern of the Wilms' tumor suppressor gene, WT1, during embryonal development suggests a role for the WT1 proteins in the differentiation of specific tissues. This notion is supported by the observation that WT1 knock-out mice fall to develop kidneys and gonads. We describe here the changes in the expression and DNA binding activity of the WT1 gene product in P19 embryonal carcinoma cells and embryonic stem cells triggered to differentiate by either retinoic acid (RA) or DMSO. In exponentially growing P19 embryonal carcinoma (EC) cells, WT1 mRNA and proteins were undetectable. During RA-induced but not DMSO-induced differentiation of P19 EC cells, WT1 expression and DNA binding are strongly activated. Treatment of embryonic stem cells with RA resulted in a similar activation of WT1. Immunohistochemical analysis showed that WT1 is expressed in endodermal, glial, and epithelial cell types. In addition, DNA binding by EGR-1, a transcription factor structurally related to WT1, increased during differentiation of P19 EC and embryonic stem cells. To investigate the possible functional consequences of DNA binding by WT1, we examined the expression levels of two putative transcriptional targets of WT1, the insulin-like growth factor 1 receptor and epidermal growth factor receptor. We found that after an initial induction, decreasing expression of the insulin-like growth factor I receptor is correlated with increasing WT1 expression. Our results demonstrate that expression of WT1 is induced in specific cell types during RA-induced differentiation of P19 EC cells, reflecting the tissue-specific expression of WT1 in vivo. Therefore, we believe that P19 EC cells are a suitable system to study activation and function of WT1 during differentiation

VALIDATION OF A 5-DOF INSTRUMENTED SPEED SKATE; TOWARDS A POWER METER FOR SPEED SKATING

Speed skates are the most important part of equipment of a speed skater, where weight, rocker and bend are just a few characteristics that are to a high degree individualized. This poses a challenge for any type of research in speed skating where forces have to be measured in a reliable manner. For this purpose, a 5 degrees of freedom (DoF) instrumented speed skate (VU-Skate) has been designed and validated, weighing only 130 gram extra. Skaters use their own blades and shoes, something skaters are very keen on. A calibration tool has been developed to calibrate the 5 DoF. The quality of the data has been validated in 2 ways: 1. With the use of force plates and 2. By comparing the signals to another (also newly developed) Ultra-light Forces sensor. The results are remarkably good. This is the first step in being able to measure power continuously during each stroke