Hey guys, just want to share something I learned over the last 5 years training with regard to barbell bench press. I used to bench heavy (5-7 reps) using a narrow grip on flat bench press trying to focus my triceps as much or more than chest..... sure this worked great..... for a while. This summer I was doing bench press (Narrow to medium grip) with 315lbs and on my final rep I felt a 'pop' in my shoulder. I finished my workout cause there was no pain at the time. The next morning I woke up with severe pain in my shoulder. I went to the Doc and he told me I had opened up my AC joint. It is now Dec and im still having trouble bench pressing with a bar. What did I learn from this?..... use dumbells as often as you can (less stress on the shoulder due to more control over the weight) Also, if you are goin to use barbell for flat bench use a wide grip (shoulder width +) instead of narrow to avoid this. Hope this will help beginners save themselves from this injury, which in the future can cause a big set back or your training.