Pressurised membranes are usually used for low cost structures (e.g. inflatable bed), impact protections (e.g air-bags) or sport balls. The last two examples deal with impacts on human body. Under-inflated protective membranes are not effective whereas over-inflated objects can cause injury at impact. The coefficient of restitution represents the ability of a membrane to dissipate energy during an impact. Its dependence on membrane properties and inflation pressure is investigated on a model experiment using a spherical membrane. Coefficient of restitution increases with inflation pressure but decreases with impact speed. For a spherical membrane, it is shown that kinetic energy is lost by transfer to vibration modes. A physical modelling of a spherical membrane impact is build considering a quasi-static impact with small indentation. Finally, the dependency of the coefficient of restitution with mechanical parameters, pressurisation and impact characteristics is given.