Lifting the head is not really a problem in it's self, its the other things that lift: legs, hips, spine, shoulders etc that cause problems.

The head is extended from the spine, it's movements are restricted by the movements of the spinal joints in the neck, what it can't do is lurch from side to side on it's own. Large shifts of the head in the swing are a symptom of sways in the torso, which we know are undesirable.