The Flexibility Trainer: biomechanical analysis of martial arts kick performances for user centred product development

<p>Winning performance in Martial Arts requires a variety of physical, physiological and technique abilities. Targeted, isolated training of the relevant body structures often significantly increases sport performance. Therefore, sports equipment specifically developed for specific requirements can be very beneficial. However, it requires multi-disciplinary insights to facilitate state-of-the-art techniques, training methods and engineering know-how. The aim of the study is to establish sufficient knowledge of Martial Arts kicking actions by in-depth biomechanical analysis and to apply it to the development and testing of a user-centred sport device.</p> <p>The cumulative dissertation comprises five papers. The first two include applications of two literature-based (sequential action and proximal-to-distal movement sequences) and two newly developed (balance and stability indicators and initiation action identification) models. Based on the outcomes, Paper 3 comprises additional novel models for performance indication, called leg and femur vector spreading angles (VSA), which allow to differentiate between skill levels of athletes with high accuracy and are strongly related to general hip joint flexibility. The final two papers focus on the development and testing of a sport device for targeted training of hip joint flexibility and strength, to ultimately improve kicking performance. The device, named 'Flexibility Trainer' was designed, manufactured, and patented within the EU. The studies showed significant correlations or group differences between sequential duration, the balance and stability models, and range-of-motion at various phases and nodes during the technique execution (particularly before and during the first kicking movement), as well as at static flexibility.</p> <p>The device was examined using general and sport specific pre- and post-exercise tests, before and after a training protocol consisting of three exercises with three repetitions each. Results show significant improvements of static flexibility and sport-specific ROM. Therefore, the device is believed to allow for a new level of efficiency in training by simultaneously increasing general and sport specific flexibility by a higher rate than found in previous studies.</p>