The effect of a custom Area Elastic Surface with different stiffness on hopping performance and safety with an emphasis on familiarity to the surface

There is no doubt that sporting surfaces are extremely important for every activity. However, there is not sufficient scientific report regarding the effect of the area elastic surface floor with common range stiffness on vertical hopping safety and performance. The aim of this study was to examine the effect of custom area elastic surface with different stiffness on the hopping performance and safety with emphasis on familiarity to the surfaces. Fifteen young and healthy experienced male were volunteered in this study. Kinematic and kinetic data recorded during hopping on four surfaces (۳۰۰-۵۰۰ kN/m) using the Motion Analysis System and AMTI force plate. In the data analysis process, leg and joint stiffness, maximum vertical ground reaction force, mechanical energy and power and angular position of joints calculated. The results of this study show that surface stiffness does not effect on the leg and joint stiffness, but after familiarity to the surface, there was a significant increase in ۴۰۰ kN/m surface positive mechanical energy and power of ankle joint and a significant decrease in negative mechanical energy and power of knee joint (P<۰.۰۵). In conclusion, it seems the change in surface stiffness after familiarity to the surface causes an improvement of hopping performance without any change in leg and joint spring stiffness. It can be proposed that deformation following impact also does not enough to significantly reduce the vertical ground reaction force.