In acrobatic sports involving equipment the rotational movements of body and equip-ment are of particular interest. They are measured and then calculated using different mathematical methods. This is the case, for example, in snowboard freestyle disci-plines where judges subjectively estimate the trick difficulty of each trick on an indi-vidual scale (International Ski and Snowboard Federation, 2022). According to Harding and James (2010), in snowboard halfpipe the judges primarily utilize the amount of rotations to rate the difficulty. Tsai et al. (2023) have shown a linear rela-tionship between the amount of rotation and the score in high level snowboard slope-style competitions. The amount of rotation is determined as the sum of rotations around all board axes and is usually included in the trick name (International Ski and Snowboard Federation, 2022). In snowboarding disciplines, the rider rides a strapped-on sports equipment, so the movement of the equipment depends on the movement of the rider, although they do not have to be identical as the body can be over- or under-rotated. To simplify matters, the board is assumed to be a rigid body during the trick in the air. Merz et al. (under review) and Merz and Schuler (2020) have shown that there are ways to perform corks and flips with a shortcut, which means with less rotation than expected by the trick name. The shortcut could enable to perform tricks with higher amount of rotation without increasing the angular velocity or airtime. Merz and Gorges (2023) showed that corks are the most performed tricks in elite snowboard halfpipe, highlighting the potential of performing tricks with shortcuts. In order to provide data-based support by developing tricks with shortcuts, it is necessary to precisely determine the amount of rotation in field. In this paper, two different methods to measure rotation are compared using the pre-defined rotation of a box. Both methods are point based. The box rotation is gener-ated within the multi-body simulation environment alaska (Institut Chemnitzer Mas-chinen- und Anlagenbau, Chemnitz, Germany). For both methods we determine the deviation of the predefined rotation and the computed rotation. In our study the box represents the bounce board of the athlete on a trampoline. A video sequence of the box movement is simulated by recording spatial coordinates of the box within alaska. Doing this, the angle of rotation alpha_sim is varied via the initial angular velocity, as well as the output frequency .. of the trajectories and the accuracy delta of the spatial coordi-nates. The objective of this study is to compare both rotation measurement methods with respect to alpha_sim, f, and delta and to determine their deviation delta_alpha in order to make a recommendation for practical use.
© Copyright 2024 15. Symposium der dvs-Sektion "Sportinformatik und Sporttechnologie": Zwischen Geistesakrobatik und praktischer Anwendung: Innovationen in der Sportinformatik und Sporttechnologie. Veröffentlicht von Technische Universität Dortmund. Alle Rechte vorbehalten.