Breaking Materials

Striking the left face of the board as it is shown Figure 2 will cause the board to break more easily than striking the right face of the board. When a board with a grain alignment similar to that shown in Figure 2 is held on the edges by a board holder and the board is struck, three forces act on the board: two forces from the board holder pushing back against the board edges and one from the board breaker who is pushing against the board center. When struck, the board bends and the backside begins to stretch and split while the front side is compressed. The grain on the left side of the board is closer together and is more easily compressed. The grain on right side is straighter than the grain on the front side and thus easier to stretch. If the board were struck from the right side, the opposite would be true making the board harder to break.

Only break in one place, so they must be hit dead center. Plastic interlocking "fingers" that create the board's resistance to breaking are susceptible to temperature. The warmer they are the easier the board is to break. Breaking resistance decreases the more times a plastic board is broken. When re-chambering the hand or foot after a break, the board fingers may dig into the arm or leg and cause injury.