The Board of Immigration Appeals (Board) has determined that an actual use of violent force is required for a crime of violence. Infliction of injury on the victim is not necessarily an indication that violent force was employed; for example, certain assault crimes may include an act of poisoning, which would not require the use of violent force. Taken these guidelines into consideration, the Board determined that a conviction for aggravated battery in Puerto Rico would not qualify as a crime of violence under 8 USC 16(a) because it criminalizes acts that do not entail the use of violent force.
The full text of Matter of Guzman Polanco can be found here: http://www.justice.gov/sites/default/files/pages/attachments/2016/02/24/3857.pdf