Regain Energy:
When given a choice to hit the heavy or speed bag between fights simply hold L1 + L2 + R1 +
R2. The amount of energy regain will depending on how long the buttons are held. 

Fight as a Bear:
While at the main menu press Right + Square, Right + Triangle, Right + Circle, Right + X. Next,
go to the character select screen and choose any boxer to fight as a bear. 

Big Head Boxers:
While at the main menu press Left + Circle, Left + Triangle, Left + Square, Left + X.

                             Game Shark Codes

     P1 Infinite Stamina - 801DA5DE 002D or 801DA606 002D 
     P1 No Stamina - 801DA5DE 0000 or 801DA606 0000 
     P1 Max Power - 801DA60C 0BB2 
     P1 No Power - 801DA60C 0000 
     P2 Infinite Stamina - 801DAF6A 002D or 801DAF92 002D 
     P2 No Stamina - 801DAF6A 0000 or 801DAF92 0000 
     P2 Max Power - 801DAF98 0BB2 
     P2 No Power - 801DAF98 0000 
     Arena Modifer - 800AF790 000? 

Create A Boxer

     Max Power - 800C12AC 0064 or 800B0A7C 0064 
     Max Speed - 800C12B0 0064 or 800B0350 0064 
     Max Stamina - 800C12B4 0064 or 800B09E0 0064 

Quantity Digits to Accompany Arena Modifier Code

     00 - Madison Square Garden 
     01 - Top Rank Arena 
     02 - Ring Magazine Arena 
     03 - Great Western Forum 
     04 - Grand Casinos 
     05 - Caesar's Palace 
     06 - Schtanzes Cajun Corner 
     07 - Generic