Anders has a blog somewhere that explains building the barre and only using parts of the barre. Which we all do in the beginning without knowing it. Check out Merce Font on you tube. A Spanish classical guitarist. Dispels the need for force and how each segment of your finger can easily cover the strings. Depending on your fingers and the nut width of your guitar the first two segments easily lie flat across the 4 highest strings and for some they can cover 5 strings. Start with one string and work across the neck. Some force needs to be built but not the white knuckle wrist stressing force we tend to think is needed. 
Dave L