Biomechanical factors that influence intra-individual variations in step frequency and length during sprinting

Abstract

1 1) 中京大学大学院 体育学研究科 〒470 0393 愛知県豊田市貝津町床立101 2) 中京大学 スポーツ科学部 〒470 0393 愛知県豊田市貝津町床立101 3) 青山学院大学 社会情報学部 〒252 5258 神奈川県相模原市中央区淵野辺 5 10 1 4) 早稲田大学 スポーツ科学学術院 〒359 1192 埼玉県所沢市三ヶ島 2 579 15 連絡先 豊嶋陵司 1. : Biomechanical factors that in‰uence intra-individual variations in step frequency and length during sprinting. Japan J. Phys. Educ. Hlth. Sport Sci. AbstractThe purpose of this study was to clarify the biomechanical factors that in‰uence intra-individual variations in step frequency (SF) and length (SL) during sprint running. One male sprinter participated as a study subject, and performed a 60-m sprint at maximal eŠort. Experiments were conducted 5 times, with a total number of 14 trials. The ground reaction force and positions of markers attached to the joints were recorded using force plates and a motion capture system. Trials were divided into SF type and SL type depending on the SF/SL ratio, and the kinematic variables and ground reaction force were compared. The main results were as follows. 1) There were no signiˆcant diŠerences in sprint velocity and stance time between the SF type and the SL type. 2) The ‰ight time of the SL type was longer than that of the SF type. 3) Vertical components of the ground reaction force and impulse during the stance phase were larger for the SL type than for the SF type. 4) The thigh angle of the swing leg was larger for the SL type than for the SF type during almost all phases. 5) The hip joint of the swing leg was ‰exed to a greater degree during the stance phase andˆrstandˆrst half of the ‰ight phase for the SL type than for the SF type. 6) There were no marked diŠerences in the segment and joint angular velocities between the SF type and the SL type. These results indicate that changes in step frequency and step length with ‰ight time are due to an increase or decrease of vertical impulse. Moreover, it was revealed that vertical impulse is in‰uenced by the thigh angle of the swing leg during the stance phase, rather than by the angular velocity of the swing leg.