Cereal grains are subjected to physical forces produced by agricultural machinery during and after harvest. The resulting physical damages have biological consequences such as reduced germination and yield. Damages may be minimized by adjusting equipment to take into account the physical resistance of grain to mechanical and dynamic loading. This paper describes methods for evaluating grain-to-ear binding force and grain physical resistance and presents the results for barley, rye, spring wheat and winter wheat varieties. Results of research on relationships between physical forces and biological effects on varieties of spring wheat and winter wheat are also presented and discussed.