Neither Sasha Mitchell nor Michel Qissi ever touched real broken glass during the final fight scene: the "glass" worn on their fists is actually silicone ice, and a fake human arm (cast from the fist of props coordinator Tighe Barry)was used in the shot wherein David Sloan rubs his fist into the container of glass shards.
The bloody footprints seen on the canvas at the end was from the Property Assistant/Intern Mark Kern, whose large feet (size 14) were painted with fake blood repeatedly so he could stomp around leaving the marks.
Tong Po (Michel Qissi) hurt himself throwing Gene LaBell out of the ring causing the local fire department to roll to the set, even though Michel was fine within an hour without the medical attention.
The arena in which the major fights take place is the Bren Events Center of the University of California, Irvine. Many of the spectators are UC Irvine students.