Have you ever seen someone lie on a bed of nails and not get hurt? Why do we slap the ground on our falling techniques? The answer to these questions lies in the concept of Pressure. Pressure is simply the Force applied divided by the Area over which that Force is applied.

Pressure [Pa = N/m2] = Pressure equals Force divided by Area.

Pressure is what really causes impact injuries. When being stabbed by a knife, the Area is extremely small (only the knife point that touches your skin) so the Pressure is large. When a person lies on a bed of nails, the total surface area is the sum of the area of each small nail point. Thus the total pressure is not large enough to cause the nails to puncture the skin. When we do the falling techniques, we lower the Pressure by increasing the Area in contact with the ground.