Like the hips, the shoulder is a ball and socket type joint capable of moving in many different directions and planes of motion. Because it is so flexible, it is also more susceptible to injury. Another factor to take into consideration is overuse, as any of you who have ever been a baseball pitcher or football quarterback know all too well. This makes it very important to treat the shoulders with caution and respect in the weight room. Always take the time to thoroughly warm up with several lightweight and high rep sets before even thinking about tackling a heavy weight. Stretching is also a wise precursor to the workout, and specific strengthening exercises for the rotator cuff muscles can often be a smart investment too. Should your rotators ever give out, training not only for the shoulders but the entire upper body is shot. Avoid ballistic lifting movements that can greatly amplify forces placed on the joints and connective tissues.