INTRODUCTION: Ski-jumping is a very complex sport. Especially the take-off poses a high challenge to the athletes. The aim of the take-off is to reach high vertical release velocity in combination with a sufficient large forward rotating angular momentum (Schwameder, 2008). Strength training of the lower limbs and imitation jumps are used to enhance the take-off performance in dry land situations. It is not known, however, if the dry land performance correlates with the actual ski-jumping performance in general and in junior ski-jumpers in particular. Thus, the aim of this study was to investigate the correlations between parameters from isometric strength tests and jump tests with the ski-jumping performance in junior ski-jumpers. METHODS: 28 junior ski-jumpers were tested concerning isometric strength parameters at different knee angles, and jump performance parameters at squat jumps and imitation jumps. Skijumping performance was determined by mean jumping distances of a competition series from the pre-season. Pearson's correlation coefficients were used to operationalize the correlations between lab tests outcome and ski-jumping performance. RESULTS: Maximum rate of force development (RFD) and jump height (h) in squat jumps (sj) showed significant correlations with ski-jumping performance. RFD_sj and h_sj correlated significantly with the same four parameters, namely jump height in imitation jumps (h_imi), maximum force in squat jumps (Fmax_sj), maximum force in isometric strength test at 70° knee angle (Fmax_70) and maximum rate of force development in isometric strength test at 70° knee angle (RFD_70). DISCUSSION: Based on the high dimension of performance determining factors the significant skijumping performance explanation rate of 28% by RFD_sj and 18% by h_sj are assessed to be surprisingly high. Furthermore, these two parameters correlate with other items of the dry land tests and consequently contribute at least partly to jumping performance. The ability to produce large forces in a short amount of time and to reach high values of maximum force at low knee angles in the static situation and in squat jumps seem to be important requirements for junior ski-jumpers to perform high level ski-jumps on the hill. CONCLUSION: To a substantial extent hill jump performance is correlated with isometric and jump specific parameters determined in a dry land setting in junior ski-jumpers. Thus, the lab tests can be used as performance diagnostic tools for this group. Additionally, it can be concluded that skijumping specific strength training with a particular focus on the age and the physical status supports the development of junior ski-jumpers. --- The hosting University of Jyväskylä is planning to publish conference proceedings "Science and Nordic Skiing III". In case you are interested in this publication please contact the editors (Anni Hakkarainen anni.s.j.hakkarainen@jyu.fi) to become registered for the book.
© Copyright 2015 3rd International Congress on Science and Nordic Skiing - ICSNS 2015. 5-8 June 2015, Vuokatti, Finland. Veröffentlicht von University of Jyväskylä; University of Salzburg. Alle Rechte vorbehalten.