knock down power is usually associated with kinetic energy, and the more kinetic energy the more knock down power. Well kinetic energy doesnt kill an animal, tissue disruption and blood loss or disruption of the nervous system is what kills. you can shoot 3000 ft/lbs of energy into the hind quarter of a deer and all that energy was disspersed into the animal but it wont kill it, put 50lb of kinetic energy through the lungs of a deer and it will expire. an arrow cuts tissue and a bullet crushes tissue, they both do the same thing just do it a little different, hydrostatic shock or temporary wound cavity is usually associatedwith velocity, and itdoes disrupt tissue but not nearly as much as the permanant wound channel created by the bullet or broadhead
Yes, knock down power is a myth.