Unilateral strength training is simply training one limb at a time. When we do squats or barbell bench press or pull-ups, we are training bilaterally - both sides of the body at the same time. Most of the time, this is a perfectly effective mode of training. There are two reasons, however, to consider training unilaterally. First, most sport movements are performed one limb at a time. Think about it: how often do you get to put both hands on the same exact hold and pull with both at the same time?