In a normal training regimen you first do the compound exercises for a certain muscle group and then the isolation exercises. Pre-exhaust means that you do it the other way around. It is a controversial training method in the evidence-based bodybuilding community.

COMPOUND VS ISOLATION EXERCISES

Compound exercises are exercises that involve multiple joints and thus other muscles in addition to the target muscle that help the target muscle. In isolation exercises, as the name suggests, you isolate the target muscle.

A good example of a compound exercise or isolation exercise is bench press and dumbbell flyes.

With the bench press, in addition to the pectoral muscles (target muscle), your triceps also take care of a large part of the work. In dumbbell flyes, where there is no bend in your elbow joint, the role of your triceps is eliminated and you mainly work your chest muscles.

Because you can perform compound exercises more heavily, do those first.

The downside to compound exercises, however, is that it’s not always the muscles you target that get tired first.

PRE-FATIGUE

With pre-fatigue, you reverse the order of the compound exercises and isolation exercises: you do the isolation exercise first and then the compound exercise. So you tire your chest muscle first with, for example, dumbbell flys before you start bench pressing.

The idea behind this is that a tired muscle (the chest in our example) has to work harder, unimpeded by weak links (in our example the triceps and shoulders).

RESEARCH

The theory behind pre-fatigue sounds interesting to bodybuilders, but does it work in practice? A dive into literature.

Both a Brazilian and Swedish study (2007 and 2003, respectively) suggest that pre-fatigue is ineffective.

The Brazilians had a group of men do chest presses and then flyes on the pec deck, as in the example just now. In another workout, they reversed this order. The Brazilians concluded that the muscle activity in the chest muscles during the chest press was higher when this exercise was done first. So the traditional order. When the pectoral muscle was pre-tired, the triceps took over much of the work.

Swedish researchers came to more or less the same conclusion in a study of the muscle activity in the quadriceps during the leg press (compound) and leg extensions (isolation). Also in this study, the activity in the target muscle was higher when the exercises were done in the traditional order.

More recent (April 2022) is another Brazilian study. Prefatigue of the latissimus dorsi muscle of the back (the ‘lats’) did not increase muscle activity (measured in EMG, electromyography) during the seated rows performed afterwards. Both exercises were trained to failure.

This and the two other studies are enough for coach and author Menno Henselmans to conclude:

Overall, the pre-exhaustion technique reduces performance, total work output and possibly total muscle activity without any clear upside. It’s generally better to perform your compound exercises for a muscle before you do their isolation work, if you do both in the same session.

CONTRADICTION

However, not all of Henselmans’ colleagues agree with him. While they recognize that pre-fatigue comes at the expense of target muscle activity, that’s exactly the point: you have to overload the target muscle so that it becomes the weakest link in the compound exercise, creating a unique growth stimulus. Greg Merritt of Muscle and Fitness says:

The weakest link fails first. In the case of pre-exhaust, that’s a good thing.

After all, the essence of doing the isolation exercise first is to tire the target muscle group. Of course, that muscle group will not be able to withstand that much load during the compound exercise and will therefore not be so activated. But that’s a good thing, because it means that muscle group will fail first.

In the chest example, if you do pec deck flyes, which isolate the chest, before the bench press, your pecs will be pre-tired when you begin the bench press. As a result, your chest will give out sooner than your shoulders or triceps (the auxiliary muscles) while pressing. This puts more strain on the chest than normal (than when training in the traditional order, when the weak links, in this case, shoulders and triceps, fail first.

NOT FOR EGO LIFTERS

We’ve seen that pre-fatigue reduces the weight you can handle during your compound exercise. It is therefore specifically a bodybuilding technique, which shows that you do not always need the highest training weight to create overload (which results in the muscle growth stimulus). Something egolifters don’t like to hear. After all, they want to use the highest possible weights.

But if you want to lift as heavy as possible, you have to become a powerlifter or strongman. If you want as much muscle mass as possible, you have to manipulate your muscles as efficiently as possible, which does not necessarily mean that you use the heaviest weight, not even in the ‘big lifts’ such as bench press and squat.

EXPERIMENT

As mentioned, the effect of pre-fatigue on muscle growth in a direct sense has not yet been studied. So it is still an experimental training method, which can be especially interesting for advanced bodybuilders. After all, as a beginner or intermediate, you should be able to work well with the traditional training protocols.

IMPLEMENT

Fortunately, you don’t have to choose and you can include different training protocols in one training program. So you can do the bench press twice a week according to different protocols: on one occasion you do the bench press first and then the pec-deck-fly, the other time you start with the pec-deck-fly and then you do the bench press . This way your chest gets a slightly different training stimulus twice a week.

FINALLY

Don’t expect miracles. But from whatever angle you look at exhaustion, it is obvious that your muscles will receive a different stimulus. If you’re looking to make that much-needed change to your schedule, usually for breaking training plateaus, it might be worth giving it a try for a while.

Pre-exhaustion Does it work?