What was the accident? 
He fell on a pool chair and cut himself pretty bad in groin area, apparently quite serious
In his (zane) words:
"in 1980, I had a bad accident right before the Olympia Contest. It was a near death experience, I almost bled to death, but I came back eight weeks before the Mr. Olympia, and I was in phenomenal shape, ready and poised to be in the best shape of my life, but after almost bleeding to death and being in the hospital for a week and a half, I lost almost fifteen pounds! So, I went into the contest anyway and I was really muscular, but I wasn’t near my best.”
In his last contest before retiring, Frank had yet another accident. He recalls, “It was as if I was self-destructing. I had a bicycle accident and tore my rotator cuff. I couldn’t lift my arm for a month! "