Two sets of concepts for sport shoe construction are discussed, based on anatomical, orthopedic, and epidemiological considerations: one for the prevention of excessive load and related injuries, and one for the improvement of performance. The proposed concepts for prevention of excessive load and related injuries in the foot and the lower extremities are cushioning, support, and guidance. The goals outlined in the concepts can be achieved by altering the material properties or the construction of the shoe. It is suggested that the concept "cushioning" is not well understood yet and needs further research. The discussed concepts for improving performance are first, that energy should be returned at the right location, at the right time, with the right frequency, and second, that loss of energy should be minimized. Reduction of energy loss is an important concept for performance. The concept "return of energy" seems inappropriate for sport shoes.