This paper sums it up. These are young men attending the NFL combine and showing positive signs of hip problems at a very young age. These problems began years before. With respect to this condition and how to train athletes who have this problem, as well as what exercises to use to prevent this, the NFL and sports medicine have no clue…BUT there is much that can be done.
http://www.ncbi.nlm.nih.gov/pubmed/22698961