Purpose: The purpose of the present study was to examine the characteristic of the sprint start movement of elite sprinters. Methods: The measurement was performed at the 100-m event of the 11th IAAF World Championships in Athletics, Osaka, Japan. The movements of four male and three female elite sprinters, whose results were 9.85-10.20 sec in male and 10.99-11.98 sec in female, recorded by four high-speed cameras (200 fps) and analyzed with direct linear transformation method. The analysis phases were during start phase (6 steps from start) and middle phase (around the 60m from start). Their running velocity, step length, and step frequency as well as the angles of joints, segments and leg during the supporting phase. The peak angular, segment and leg swing velocities were calculated. The leg swing angle of the supporting leg was defined as the angle between a line from the trochanter major to the lateral malleolus and a perpendicular line from the trochanter major to the ground. Results and Discussion: The leg swing velocity and forward rotation velocities of the thigh and shank segments were higher with increasing steps. During the start phase, the forward rotation velocity of the thigh segment was already reached those during the middle phase. However, the forward rotation velocity of the shank segment was significantly lower during the start phase than during the middle phase. Therefore, the leg swing velocity during the start phase can be obtained mainly due to the increment of the forward rotation velocity of the thigh segment. The previous study had reported that the knee joint during the foot contact phase should not be extended to transfer the hip extension velocity effectively to the leg swing velocity during the middle phase (Ito et al., 1998). During the start phase, however, the extension velocity of the knee joint and the amplitudes of the knee joint changes were greater in the start phase than in the middle phase. In addition, the angle of the shank segment was smaller as compared to that during the middle phase. It is likely that the elite sprinters could obtain the leg swing velocity by the knee extension due to the forward rotation of the thigh segment during the start phase.
© Copyright 2009 14th annual Congress of the European College of Sport Science, Oslo/Norway, June 24-27, 2009, Book of Abstracts. Veröffentlicht von The Norwegian School of Sport Sciences. Alle Rechte vorbehalten.