IN SITU EVALUATION OF THE CUSHIONING CHARACTERISTICS OF DIFFERENT SPORT SHOE MIDSOLES N. Vignais 1 , E. Badier 1 , A. Marin 1 and B. Bideau 1 1. ABSTRACT The capacity of sport shoe midsoles to attenuate impact during ground contact has been largely studied for activities such as walking and running. However, shoe midsoles have also a key impact in more jumping and landing sports like volleyball or basketball for example. Only few data are available concerning shock transmission and reduction throughout this kind of activities. The aim of this study is to compare three sport shoe midsole capacities during different dynamical tasks (Squat Jump, Drop Jump and Landing Test). We analyzed the cushioning capacities of midsoles in three different footwear conditions by comparing dynamical data from a Pedar System (foot/midsole forces) and from a force plate (midsole/ground forces). The results showed that sport shoe midsoles have different dynamical absorption capacities during leaving the ground and landing phases (p<0.05). Sport shoe midsoles capacities have been evaluated by using a coupled dynamical measure. This study has compared the cushioning characteristics of different sport shoe midsoles in situ. This methodology could be used in order to adapt the sport shoe midsole to the practiced activity. 2. INTRODUCTION A sport shoe is composed of three main parts. The first one corresponds to the upper and tongue, which can protect the foot from temperature and humidity and which can stabilize the foot with lateral supports and heel counter. The second one is associated with the outer sole, which has to prevent the shoe from wear and tear. And the last one concerns the midsole which plays an important role in a sport shoe (Chiu et Shiang, 2007). Firstly, the midsole has to improve the performance of the movement by decreasing energy lost between the foot and the athlete (Reinschmidt et Nigg, 2000; Stefanyshyn et Nigg, 2000). Secondly, the midsole part must prevent the subject against injuries. To this aim, the midsole has to stabilize footing (by the role of the medial post for example) and to absorb impact forces (by the foam layer and the cushioning technology) (Roux et al., 2009). This last capacity is an important concept and it has been largely studied throughout the literature (Bobbert et al., 1992; Stüssi et al., 1993; Fong et al., 2007). The cushioning capacities of a sport shoe midsole can be evaluated by different methods. The first one corresponds to an indirect evaluation. By using shoe impact testing, manufacturers can compute the difference between initial and final vertical stress which corresponds to the cushion value. But this kind of measure does not 1 Movement, Sport and Health Laboratory, UFR APS, Rennes 2 University, Avenue Charles Tillon, 35000 Rennes, France. www.m2slab.com