Samson Diener didn’t plan on becoming a boxer. What started as a five-week commitment to represent his fraternity turned into nightly practices, strict discipline, and a growing list of fights.Between classes, training sessions, and meal prepping in a crockpot that he stored under his bed, the University of Iowa criminal justice major has built a lifestyle around the sport. But in the ring, that consistency takes on a different form.

Samson Diener didn’t plan on becoming a boxer. What started a...