The Italian striker is desperate to remain fit at the Stadium of Light following a debut season at Anfield blighted by injuries.
"Last season was tough, mostly because of the injuries, not the move," he told the Sunderland Echo.
"Big-money moves happen in football. So do injuries, but they take you down, especially when all you want is to do well for a new team. Basically, your body pulls you out.
"I wanted to prove myself at Liverpool last season and I couldn't really do it. I've come here to do that now."
Borini was forced to undergo surgery three times last season due to foot and shoulder problems.