INTRODUCTION: The assessment of biomechanical Parameters in freestyle skiing is of major importance as remarkable changes in equipment design and movement patterns (technique) have occurred in the past decade. Measurement Systems need to be designed to fulfill the requirements of reliable on-snow data collection[1]. Such advanced technologies have great potential but may be compromised by affecting riding style and skier perception by adding mass or changing the geometry of the ski-boot interface. The purpose of this study was to examine the effects of using a force measurement device on riding technique in mogul skiing. A simulated version of the device was positioned between ski boot and binding. The current study was designed as a prerequisite for further comprehensive biomechanical research in snow sports. METHODS: Eight subjects (2 females, 6 males) of advanced skill level were instructed to ski down a mogul course of 35° inclination. The distance between subsequent moguls was four metres. Kinematic data was collected at 101 Hz, using four high speed cameras. Three runs were completed with Standard equipment and four runs with the mock-up device. Between the filming of the first and the second mock-up run, the subjects performed five familiarisation-runs using the device. After the first and the last mock-up run skiers completed a questionnaire relating the perception of their performance to the runs with Standard skiing equipment. Parameters analysed were knee angle, side tilt as well as forward lean of the trunk, and the path of the body's centre of mass. Data were processed off-line using Simi Motion Software and statistically analysed using SPSS 15.0. RESULTS & DISCUSSION: Perception ratings showed no significant effects following the familiarisatioin period. However, "Safety" was compromised but significantly improved over the familiarisation runs. For the factor "Edging" the subjects rated both the first and the last run significantly better than the normal runs. AH other assessed components showed a trend of improvement from the first to last run, thus suggesting familiarisation was achieved. Kinematic analysis revealed that no sign. Changes — The knee angles ranged from 75° to 120° but did not demonstrate any significant changes between runs. Further parameters are not finally analysed but results will be presented at the Conference. CONCLUSION: Preliminary results suggest that the dimensions of the modified measurement unit did not have significant effects on the riding technique of the skier. Therefore, it is intended to further develop a functional forceplate similar to [1] for future studies in freestyle skiing in order to investigate joint loading and performance in terms of injury prevention strategies.
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