Sprinter sit up is definitely a hard thing to do, what more if it's combined with pike push ups! I wouldn't know what could happen to my body if I will do this kind of training! Though there is a big desire for me to achieve all these routines, I don't think my body can carry all these challenges. My body might give up easily. But I need to start on the basic! If I will do that, there's a huge possibility of me reaching the point wherein everything is going to be a piece of cake for me!