The principle of training with compound exercises before moving on to isolation movements is a well-known rule of thumb for gaining mass in bodybuilding circles for a long time now, commonly referred to as the “size principle of motor unit recruitment”.
The reason for this is that compound exercises target a number of large muscle groups, resulting with the recruitment of many different muscle fibers, compared to isolation exercises that are designed to target specific small muscle groups. And the bigger the number of muscle fibers being utilized during a certain movement, the bigger the muscle growth.
So if you want to reach maximum growth in as little time as possible, your training should mainly consist of complex, compound movements paired with heavy weights. Then, there are two ways of including isolation exercises in your training. According to the first one, after you reach your initial objective of considerably bulking up, you can progress to adding more isolation techniques to your routine to let’s say, sculpt some finer detail onto your bulging muscles. Or you could also perform both compound and isolation movements in your regular routine, as long as you perform compound exercises first.
This seemed like the ultimate recipe for fastest results in terms of muscle growth until a recent critical review in the Journal of Medicina Sportiva declared a strongly opposing view. The paper discussed the validity of the proposed connection between exercise sequence and muscle growth and reported that two new studies have failed to find substantial evidence to support the “size principle of motor unit recruitment” theory. In other words, these studies found no significant difference in strength gains and muscular hypertrophy between the group of participants who first performed exercises that target large muscle groups and the group who first performed isolation exercises.
Furthermore, when repetitions were standardized for workouts comparing the performance of both types of exercises as first, the results were the same. This is very important because controlling the number of repetitions is an essential aspect of validity and the only way to truly compare the gains of these two groups with different routines is to have both groups complete the same number of reps of every movement.
The lead author of the paper eventually concluded, “There is very little evidence to suggest that any specific sequence of exercise strength gains or muscular hypertrophy.” In the end, the point of his critical analysis is to encourage gym goers to finally break the mold by concluding that, scientifically speaking, the tendency to perform compound exercises before isolation exercises is unjustified. In fact, all of our theories about the perfect sequence of exercise lack any serious scientific evidence to back them up so maybe we should focus a lot more on form and volume than the exact order of exercises in our training routines. That doesn’t sound too crazy, right?
Do you agree with this perspective? What is your experience? Hit us with your opinions and comments in the section below!