The purpose of this study was to determine the reliability of model-based image-matching (MBIM) technique while analyzing sport specific movement and compare training situation to real game situation using this technique. First, we investigated intra- and inter-rater reliability of MBIM in real soccer game situation. Ratings were used intraclass correlation coefficient (ICC). Overall intra- and inter-rater agreements ranged from good to excellent (ICC > 0.83), combined with pelvic movement in horizontal plane. These results suggest that it is very important to match pelvis with great precision using MBIM. Secondly, we conducted three-dimensional motion reconstruction from two video sequences, one is a training situation and another is a real game situation, by MBIM technique. Each scene is a defensive situation responding to dribble attacking in the vital area. Changes of direction scenes of defensive soccer player were analyzed. Trunk, hip, knee kinematics and peak ground reaction force for two cases were measured. Trunk forward angular displacement in real game situation is larger than that in training situation. Peak vertical ground reaction force occurred at the timing of trunk forward inclination angle of approximately 40° and trunk lateral inclination angle of approximately 10°. These findings suggested that stability and optimal angles of the trunk is an important factor for the change of direction performance during defensive soccer situations.
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