Board press is used for building power lockouts. It is similar to pin presses, except for that when the bar unloads on the boards (which are on your chest,) the weight is then transfered into the chest, shoulders and arms. As in with the pin press, the weight is transfered onto the pins.
Let the board sink into the chest, then violently explode up. A close grip is recommend, however, the more boards you use (2, 3 or 4 board) the narrower the grip.
This movement really requires 2 spots, one to hold the board and one to help unload/reload the bar.
This movement can be worked up to a 1/3/5 rep PR.