ABSTRACT
In ski jumping, take-off action is the most important factor for having ascent force (1). Ascent force acts on the ground (2) and is required for a jumper to obtain initial velocity and angular momentum. These kinetic parameters can be determined by video analysis (3). Virmavirta et al. directly measured the take-off forces of jumpers in ski-jumping competitions (2) (4) (5) (6). They showed that take-off force affected the flight length. Their study suggested the importance of the utilization of an appropriate take-off technique (6). Take-off force is produced by joint movement (2) (5). In take-off technique, appropriate movements of the joints and body segments should be aimed for, because reaction force is the result of the integrated kinetic parameters of each joint or segment. Those kinetic parameters can be determined by the analysis of jump action (7).
