The batter has rotated to the launch position and completed his timing step. All forward movement of the body has halted and he is ready to initiate the swing.
Lead arm is across chest and fully extended toward the catcher.
Back elbow is lowering past the mid-way point. The lead knee has started rotating around toward the pitcher. All slack has been taken out of lead arm so that any rotation of the shoulders will cause a corresponding acceleration of the hands. There is ample flex in the lead leg to extend and help drive rotation. He has read the pitch and ready to fully initiate the swing.