Working your muscles through a full range of motion is almost always a good idea. It'll develop your muscles to their greatest potential and accelerate your gains. However, there are a couple of things you must consider. It's important to keep tension on the working muscles and increase the time under tension for each and every set. One advanced method to achieve this is called continuous tension sets, which is a technique that defies the time-honored tradition of locking out every rep. Just stop right before the weights are locked out at the top and proceed directly into the next rep.
