The First Step: Which Is Better, The Childrens Sprint (50m Running) With Shoes Or Without Shoes?- From The Viewpoint Of 2 Dimensional Biomechanical Motion Analyze

Introduction
Many Japanese children say, " I can run faster without shoes than with shoes! ". Several teachers in the elementary
school measured the time of the children’s 50m running with shoes and without shoes. About 2/3 children ran faster
without shoes than with shoes. But there is no study about the mechanisms. The purpose of this study is to research the
biomechanical reason as the fast step, if children can run faster without shoes than with shoes.

Methods
In the experiment 1 subjects were an 8-year-old girl, a 9-year-old boy, a 10-year-old girl, a 13-year-old girl, over 40
year-old man and woman. All subjects ran 50m with shoes, the time of the each 10m was measured, and the running
velocity of the each 10m was calculated. The running velocity between 20m and 30m of 5 subjects were fastest, the
velocity between 30m and 40m of 1 subject was fastest. In the experiment 2 the high-speed video camera (made by
NAC) was set up at the place where man can film at the 30m surrounding. All subjects ran for 50m 3 times with shoes
and 3 times without shoes. The running motions of all subjects were filmed by the film rate of 1/250. The video films of
the each fastest running with shoes and without shoes in all subjects were analyzed with motion analysis software,
DYNAS by Shin Osaka Shokai Co. Ltd.

Results
Only children’s each running time without shoes were faster than that with shoes. 3 parameters, knee lift angle, knee
angular velocity and swing-back velocity in the analyzed 29 parameters were increased in all children (Tab.1).

Discussion and Conclusion
Ae.M et al. showed relationship between the swing-back velocity immediately before foot contact of the driving leg and
the sprint velocity in the world-class sprinter [1], [2]. In this study when children ran without shoes, the swing-back
velocity immediately before contact of driving leg was increasing, and the sprint velocity was increasing, too. It is
suggested if children run without shoes, they can run with the similar leg motion to world-class sprinter. But children
should run with shoes for their safety. We must study with more subjects, and what kind of shoes do children need to
increase the sprint velocity with better leg motion like a world-class sprinter and to run with safety.

References
[1]. Ito. A. et al(1994)., Journal Of Biomechanics, Vol.27, No.6, 670
[2]. Ae. M., et al(1992)., New Studies In Athletics, Vol.7, No.1, 50

NOTA: O texto com a iconografia está no anexo

Arquivo