Abstract: Objective This research focuses on the friction characteristics of different shoes on different surfaces while walking and running by analyzing the friction coefficient and relative parameters. The target is to compare the friction characteristics between different shoes and different surfaces. Methods 30 students wearing five different sport shoes are tested while walking or running on different surfaces of steel, plastic, wood and artificial grass. Kistler Force Platform is used to test their kinetic parameters. Results (1) while walking and running, the variation of friction coefficient is an "S" curve where two peaks appear at taking off and touching down period. The second peak is the maximum value of friction coefficient during the single-leg support phase |CoFy|m(the absolute value of maximum friction coefficient along the movement direction); The walking |CoFy|m appears at about late 10% of the whole period, while the running |CoFy|m , late 6%; (2)There is negative correlation between maximum friction coefficient and its time ratio during the touching face, and this correlation is quite different between walking and running. During the taking off phase, there is positive correlation between these two indexes; (3) The friction characteristics of wearing different shoes on different surfaces are quite different. Therefore, it is important to consider the actual movement when analyzing the friction characteristics of sport shoes.

Key words: sport shoes, test surface, friction coefficient, time ratio