The frontside is to rotate 180 ° (skate and skateboarder) backwards. Everything is in the shoulder movement, when you type the skateboard make a rotation of your chest 90 degrees to the rear. The rest of your body and the board will follow. The backside 180 is to make the frontside but in the forward. Look carefully the position of the feet and the direction in which the skater scratches on the videos in slow motion below.