ST isn't a force field as said above. It is the manipulation of repulsive force. By doing that the user doesn't have to witty about that force reaching him back unless the object he pushes resists it like Naruto in 6 tails mode.
One more thing. Why does the user of the force field have to be "connected" yup the field. They can just create it and it will be the equivalent of a very dense and strong wall or the walls properties can be that of being able to dissipate force along its surface so the force it is blocking didn't hit the user.
One more thing. Why does the user of the force field have to be "connected" yup the field. They can just create it and it will be the equivalent of a very dense and strong wall or the walls properties can be that of being able to dissipate force along its surface so the force it is blocking didn't hit the user.