A bow with a switch near the grip which if flipped locks the bow into full draw (very, very low let off),
flip the switch back and you have regular let off tension.

For all you doubters, it has a stem sticking out to hold the string in place (about 1" to the side of path of string) so it doesn't go slack.

It is designed to minimize your draw movement. Pull string off stem, flip switch, and you are ready to shoot.

I have my sources.