وَلَا يُصَلِّي الَّذِي يَرْكَعُ وَيَسْجُدُ خَلْفَ الْمُومِئِ.
Meaning: A person able to perform actual bowing and prostration does not pray behind an imam performing those acts by gestures.
A mūmi’ performs gestures in place of bowing or prostration due to incapacity. The stated Hanafi rule does not permit a person capable of the original actions to follow an imam using their substitutes.