today i was doing my 5x5 and i was on the fifth set and fifth rep and dident have a spotter not a good idea i know, but i had no choice. I was doing 210 lbs on bench and i got stuck and i was pushing as hard as possible up and nothing would happen and the bar just kept getting closer to my neck so on one last try i arched my back and pushed and the bar flew up in the air like nothing. That was the first time ive ever arched my back ive seen people do it but it just looked painful and i realized if i did that my bench would go from a now 250 to probly about 270.