INJURED WAS HELPING TWO OTHERS PUSH A 3-WHEEL MANTRIP BUGGY THE LAST FEW BREAKS TO THE SURFACE & INJURED HIS BACK. HE TOLD NO ONE OF HIS INJURY UNTIL 3/25/02 AT WHICH TIME HE NOTIFIED THE COMP ANY OVER TELEPHONE THAT HE HAD A CRACKED BACK. INJURED'S FIRST DAY OFF WAS 3/21/02.