Miles himself was in a near-fatal car crash just one year before his friend died in a car crash. He now wears a green bracelet that reads "Buckle up for Bo" in his honor. The bracelet can be seen in most of his films except for when it doesn't fit his character.
The movie was filmed in 24 days on a budget of six million dollars, according to an interview with Ben Younger on KCRW's The Treatment.
James Burch field Jr is portraying his dad, James Burch field Sr.
Miles Teller trained with boxing trainer Darrell Foster, who'd trained fighters like Sugar Ray Leonard and helped Will Smith become Muhammad Ali for 2001's Ali.
After the first fight the doctor says Vinny is in ketosis. This is a condition in which there is so little sugar in the body that fat is broken into ketones for energy. For diabetics this can be fatal, but ketogenic diets are well known for weight loss and even being studied for control of epilepsy.