Conditioning exercises in ski jumping: biomechanical relationship of squat jumps, imitation jumps, and hill jumps - Lorenzetti, S.; Ammann, F.; Windmüller, S.; Häberle, R.; Müller, S.; Gross, M.; Plüss, M.; Plüss, S.; Schödler, B.; Hübner, K. (Sports Biomechanics, 2019)