"A natural result of training is that progress slows down after progress has been made, and progress is why we train." - Mark RippetoeA great quote from Mark Rippetoe, illustrated in the graph above. Part of being an inexperienced trainee is that the 'rate of adaption' is so high, progress can (potentially) be realized every workout. Naturally this rate of adaptation will slow down, PR's do not come as often. It is nothing to be discouraged about, as the graph shows above, it is part of the plan. In order to keep the progress going (why we train), more and more complex programming is required.
Back Squat 3x5 or 3x3 or 1RM