1. You have to really work very hard to maintain a healthy attitude, because of back bends almost automatically by the pressure in the neck. The position of the elbow (slightly earlier) there is a tendency in addition to rotate shoulders forward also.
2. At higher weight presses the metal strip on the enormous ribs, one can indeed protect these little by tensing the abdominal muscles, but you should actually focus more on the biceps. In addition, the bar is normal white almost directly under the breast where hardly muscles in front of the ribs. When it hangs a little lower, so that they almost completely dependent from the abdominal muscles, the problem arises that the whole weight is on the top of the elbow, which after a few repetitions can also be somewhat painful.
