Instructions
Start a new bowling game in "Kinect Sports."
Line your player up so his arm is directly down the center of the lane. When the bowling ball strikes the center pin without curving, it makes it impossible to hit the outermost pins.
Swing your arm back and then forth like a real bowling ball, not allowing your wrist or elbow to twist in any way. If done properly, you will be left with a split in the pins.
Aim for the outer edge of the left-hand pin. The trick to clearing a split is to hit one pin in a way that it flies across the lane and strikes the other pin.
Swing your arm again to throw the ball. If done properly, you will knock the rest of the pins down, earning a spare and the achievement.