Taking a step forward on OHP

[Tao]

I press about 175 3x5. The last rep or two on the second and third set feels pretty heavy and though I don't bend my knees or go up on my toes, I am sometimes forced to take a step forward with one foot as I power the weight up. Is this cheating? is there any harm is doing this?

[Mark Rippetoe]

It's not cheating. You're off-balance, with the bar moving forward instead of up. Clean up your technique and you'll press more weight.