Studies of have shown that the discs in your spine are swollen up to twice the normal size when you first wake up in the morning.  With light activity, the swelling reduces after about 2 hours.  Before you set your alarm clock next Saturday morning before that tournament, consider adding those 2 hours to help your back reach its peak potential:
 
Wake up at 6am
Light walk, breakfast, stretching, light jog 6am-8am
Start practice on the table 8am
First tournament match 9am