AN ACR FLC STARTED THEIR ENGS WITH ALL THROTTLES ADVANCED 1 KNOB. THE TOW BAR WAS BENT.

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DURING PUSHBACK AND ENG START; THE TUG DRIVER WAS MANEUVERING TO AVOID SOME EQUIP ON THE RAMP. DUE TO THE CONGESTION ON THE RAMP; I WAS MONITORING THE OUTSIDE PROGRESS OF THE ACFT. UNKNOWN TO ME OR MY CREW; THE THRUST LEVERS HAD BEEN MOVED SLIGHTLY FORWARD OF THE IDLE RANGE. WE DID NOT NOTICE THAT THEY WERE ADVANCED APPROX 1 KNOB WIDTH DUE TO THE FACT THAT THEY WERE SYMMETRICAL. AS THE ENGS WERE STARTED; AND WHILE BEING PUSHED BACK AND MANEUVERED BY THE TUG; FORWARD THRUST WAS PRODUCED AS THE ENGS SPOOLED UP. THE TUG DRIVER WAS THE FIRST TO NOTICE THE MOVEMENT; AND CALLED FOR ME TO USE THE BRAKES AND ABORT THE START PROCESS. I DID SO; BUT NOT BEFORE THE TOW BAR WAS DAMAGED. (THE ACFT; TUG AND GND PERSONNEL WERE ALL UNHARMED.) I WILL CERTAINLY IN THE FUTURE DOUBLE-CHK; PRIOR TO PUSHBACK; TO CONFIRM THAT THE THRUST LEVERS ARE INDEED IN IDLE. I HAVE ALSO SUGGESTED TO MY COMPANY THAT WE INSTITUTE A POLICY TO MAKE THIS STEP A PROC PRIOR TO TELLING THE TUG DRIVER THAT IT IS CLR TO BEGIN THE PUSHBACK.