The concept of a strong shoulder is pedagogical, the goal is to give the carrier the indications on his first carries while keeping his habits and reflexes already acquired with the baby. During a workshop, we ask the parents to spontaneously hold a weighted baby, without any other indication from the instructor. The shoulder spontaneously chosen is the one we will consider as "strong". We notice that it is easier for the carrier to start carrying the baby this way.
In a positioning from the Main Knot (Profile or Ventral Sitting) the upper strap is on the strong shoulder, the baby is first placed on this shoulder and then placed in the lower strap which is on the opposite side. The carrier will find this first manoeuvre easier and will approach it with more ease. This reflection on the strong shoulder applies to the carrying of a newborn in the Basic Node. For the Side/Hip carry, people tend to confuse the strong shoulder with the carrying hip (when they can be opposite). In this case, if the person is using the Basic Knot (Hip Strap Down), they could possibly change the side strap.