The shoulders might have been above the waist (not convinced myself) but 87's movement was downward and toward his knees and legs as he made contact. That play is very dangerous (and against the rules) and a player needs to recognize that and pull up. It would have been different if he had been closer and able to deliver a blow to his back that pushed him forward. That is merely a block in the back. That play he made has a high likelihood of hurting someone as you roll down into his legs. It was really a bad decision and Arnell get's to pay for it.