see osa vasara löögienergiast, mis otseselt kulub tooriku plastsele deformeerimisele (vt löögienergia), nominal energy of a hammer transformed into useful energy available for deformation; efficiency varies from 0.8 to 0.9 for soft blows (small load and large displacement) and 0.2 to 0.5 for hard blows (high load and small displacement) (see: blow energy)