We've all seen hardcore lifters who look to be in a perpetually slumped-forward state. Their chest muscles have been built up, but their back muscles haven't gotten the same amount of attention. This pulls their shoulders forward, and they seem to hunch. Looking at your T-shirt is a good way to see if you've been overtraining or undertraining part of your body. [caption id="" align="aligncenter" width="504"] Source: allenantiques.com[/caption] Stand up straight as you look in the mirror, and check the shoulder seam of your T-shirt. If the stitching forms a straight line between your neck and shoulders, it means your muscles have been developed evenly. If, however, the seam runs forward--toward your anterior deltoids--it means you have overdeveloped your chest muscles or underdeveloped your back muscles. If this happens, it's time to pay more attention to the muscles of your back. If you don't your posture will suffer as a result, and you may begin to suffer from pretty serious structural problems. Trust me, as a back pain sufferer, you want to avoid this at all costs!