The validity and relevance of tests used for the assessment of sports surfaces

Inappropriate cushioning and/or tractional characteristics of sports surfaces are assumed to increase surface-related injuries in various sports activities. Various tests assessing cushioning and frictional properties are currently in use to evaluate sports surfaces with respect to their potential to reduce the number of surface-related injuries. A critical review of the currently used test procedures showed that most of them are not relevant. The main shortcomings are 1) errors in the measured test results by not correcting for inertia terms due to moving test foot or surface sample, 2) use of inadequate material test procedures where the test procedure influences significantly the test result, and 3) use of material test procedures where the used materials or the applied forces are not representative of the actual situation during sport activities. It is suggested that appropriate test batteries should include 1) test procedures that determine the material properties (stress-strain relation and traction coefficients) relevant for the surface-shoe interaction and 2) subject tests that describe the adaptation of the athlete to the surface-shoe-athlete situation.