Lets take a closer look at a technique called Triple Drop Pre-Exhaust training and how we can apply it to a shoulder workout.
Pre-exhaust involves using an isolation exercise immediately before a compound exercise to pre-fatigue the muscle without involving the secondary muscle groups. For example, to pre-exhaust the pecs you would do a set of pec-deck or lying dumbbell flyes to failure immediately followed by flat or incline bench press.
The idea is this: The pec-deck or flyes works the pecs without involving the delts or triceps. So although your pecs are fatigued, your delts and tris are fresh so you can further blast your pecs by doing a set of bench presses immediately after the pec-deck or flyes.
I like another technique that utilizes the pre-exhaust idea in a different manner. In this issue let's use shoulders for example. Pick an isolation exercise for the shoulders. I like side dumbbell lateral raises. If you have access to the nautilus side lateral machine then that's a good choice, too.
Select a weight that will allow you to complete 10 to 12 reps of the side lateral raises in good form with the last rep being the last one you can possibly complete without help. In other words, go to temporary muscular failure. Immediately reduce the weight approx. 30% and do another set without resting. Take that set to failure for however many reps you can complete. Again immediately reduce the weight approx. 30% and do a third set without resting. Take this third set to failure for however many reps you can complete.
Now rest about a minute and do a compound exercise for your shoulders. Let's use seated dumbbell presses for this example.
Your shoulders should be fairly fatigued if you performed the side lateral raises as intensely as I described.
Select a weight that allows you to complete 10 to 12 reps of the seated dumbbell press to temporary muscular failure. The weight you'll use will probably be significantly less than you normally use because of the pre-exhaust we did on the side lateral raises.
Now just like on the side lateral raises, complete your first set to failure then immediately reduce the weight approx. 30% and do a second set without resting. Again immediately reduce the weight approx. 30% and do a third set to failure without resting.
This is a pretty intense technique and should probably only be utilized very sporadically. In fact, I would recommend waiting at least 7 days before you train shoulders again after a session of Triple Drop Pre-Exhaust.
Source White Market