Use the Performance Institute on the day of a game. Save the game to a memory 
card, then remove the memory card. Next, simulate the game, then exit the game 
without saving. Insert the memory card back in and load your superstar. You will 
be able to use the Performance Institute again while still retaining the 
benefits gained from the last time you used it. Repeat this process as many 
times as desired to raise all Performance Institute stats. -From: Brian 
Hernandez