Engineering practice shows that the design of modern structures and technical components requires adapting existing methods for testing materials to dynamic load conditions. This work discusses the experimental and theoretical basis for determining and predicting critical stresses in quasi-brittle materials (such as concrete, rock, organic glass, etc.) over a wide range of loading rates provided by different test methods and equipment. Standard tests for compression, splitting and bending are presented. The incubation time approach is used as a unified approach for determining the dynamic strength of the materials. It is shown that critical stresses in the materials under a wide range of high-speed loads can be estimated based on two strength parameters.