A shoe sole having a bottom surface with a plurality of stud clusters extending therefrom is provided, each stud cluster comprising at least two studs connected via one or more connection elements, wherein, to optimise the manner in which the stud clusters deal with forces applied to them during ground contact, each stud cluster is oriented in accordance with a predetermined direction of gross shear motion of the stud cluster and each stud cluster is dimensioned in accordance with the distribution of forces applied to the sole during ground contact.