Very Hard. Very, very hard. I did this something like six, seven times consecutive. So up and down. Up and down every time. One round stand up position. One round under. Lets call this Mambo Hell Drill because you pass down and up. But its very useful to train the transition between the stand up position and ground position. Very good drill for fitness, for aiming, for trigger. To set the finger with the upper and lower body during a dynamic action. Very very useful.