Purpose: The purpose of the present study was to examine the characteristics of lower limb`s movements around the top sprint speed phase of elite sprinters. Especially, it focused on the movements of the thigh and shank segments during the contact phase. Methods: The subjects were 6 male (9.85-11.24 sec) and 6 female (10.99-13.10 sec) sprinters, who participated in a 100-m races in 11th IAAF World Championships in Athletics, Osaka, Japan. Their running movements of one stride at approximately 60-m point were recorded by two high-speed video cameras (200fps) and calculated the following parameters with three-dimensional direct linear transformation method: average running velocity during the one stride, step length and step frequency as well as the average segment and joint angles of legs during the contact phase. The contact phase was divided into the ratio of 43% and 57% as the deceleration and acceleration phases, respectively. These phases were defined by the previous study (Fukuda et al., 2004) which calculated from the horizontal components of the ground reaction forces. Results and Discussion: The average angular velocity of the shank segment during the deceleration and acceleration phases were positively related to their running velocity. In these subjects, the average angular velocity of the shank during the deceleration phase was slightly higher than that of the thigh. It is likely that the greater forward rotation velocity of the shank segment could be occurred by the deceleration force of the initial impact. Consequently, the angular velocity of the knee joint showed a flexor direction during the deceleration phase. During the acceleration phase, on the other hand, the average angular velocity of the thigh segment increased, especially for the lower sprint velocity group, and did not showed any significant difference with that of shank segment. However, the average angular velocity of shank segment decreased similarly to all of them from the deceleration to acceleration phase. Consequently, the knee joint extended during the acceleration phase in the lower sprint velocity group. These results suggest that the elite sprinters can be hardly extended of the knee during the acceleration phase due to the greater angular velocity of shank segment. This is likely that elite sprinters could be transferred angular velocity of thigh segment effectively to the leg swing velocity.
© 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. / Übersetzt mit https://www.DeepL.com/Translator