* reverse vector is a term taken from navigation. It means the opposite direction or going back on your tracks. Ig you are rolling forward than point your fingers to where you are going. They don’t have to be rigid unless you find it useful for your movement or they can point to where you are coming from as a fixing point to draw attention, as a draw point or to create a form fit for the roll. Consider this. Take a gun or a knife and point it in one direction and move it forward and backwards. Now point a finger at a point and check your accuracy. Sounds strange does it not ? You know how to aim with you finger naturally. Use it as you aim a point or a gun and leave the tension behind you. As you close you hand the fist becomes the end of the limb and takes that place. Think about this.
Now if you wish to make contact with the floor with a hand before you engage the body which makes sense if you are working in the dark or have no clear line of sight as in entering with a roll. If you place the palm on the floor than the end of you points in a direction that is almost perpendicular to where you wish to go. It can harm your badly and create an impact that is on the spot as you collide with the floor in the meeting of these vectors ( draw a line for each direction and see where they meet. They do so in the ground deep and that is not where you want to go… ) When you place the back of the hand on the floor it has no placing since it is not a gripping tool and you may slide and hurt your self. Consider rolling slowly from kneeling at first and using the back of the hand if you must only as a point of reference so you know where the floor is and put no mass on it. Better yet, Try rolling from a prone position (shooting term meaning on your belly flat) Start from bringing your legs over one shoulder and keeping relaxed while also rotating the shoulder. That way you experience rolling with the core breath rather than hinging yourself on the limb. Same goes for the front roll as you rotate the shoulder and bring your body over it.