Just an easy way to get some extra rep work after your heavy set(s). Sometimes people use backoff sets to get an extra pump in the muscles. Me, I've used multiple backoff sets after my max bench set just because I need the extra work on exploding the weight.
Sometimes people will "rep out." Or go to exhaustion on lighter weights. So instead of going slightly lighter for 5 reps, maybe go much lighter for 8 - 12 reps.
Bogdan Petia Sarac - Must keel moose and squirrel
Cancer Survivor - 7/21/10
Benchmark 5K time: 27:45 (3/5/11)
It's not the weight we move, but the people we move that matters. -- Bearded Beast of Duloc (12/31/10)