Do Pre-exhaustion Techniques Work?
By Josh Bryant, MFS, CSCS, PES | ProSource
Performing Isolation Movements Prior to Compound Lifts Maximizes Mass Gains: Fact or Fiction?
Before we start, let's agree to agree: Compound movements are the nucleus of any legitimate size or strength building program. This is what science and experience tell us.
People who want a short cut, mostly. The rest of us know that, when it comes to resistance training, the path of least resistance is usually the path of least results.
Heavy compound movements are the priority. So, approach them mentally and physically fresh.
Heavy or Light Weights
No less an authority than 8-time Mr. Olympia Dorian Yates has stated that top strength athletes in heavyweight classes have more muscle mass than pro bodybuilders. This statement does NOT include -- drum roll, please -- eight-time Mr. Olympia Ronnie Coleman. Coleman is a bodybuilder who was also one of the strongest men in the world. It's not a coincidence that no one has ever come close to the level of Ronnie Coleman before or after his reign as eight-time Mr. Olympia.
Bottom line, there is a direct correlation between strength and muscle size. The line is rarely blurred; the exceptions are the very rare genetic freaks and guys loaded up with obscene amounts of drugs.
The Myth Starts in the Lab
Poorly designed studies perpetuate myths.
One study by McMaster University of Canada showed no difference between heavy and light loads for muscle hypertrophy. The study basically showed, when training to failure, light weights increase muscle size as much as heavy weights. Scientists compared the effects of workouts ranging from 30% of a 1RM to 80% of a 1RM.
Let's scrutinize the weaknesses in the study. ¨The subjects had no formal weightlifting experience and had no regular lifting activity over the prior year. In other words, when it came to heavy pig iron, they were virgins. In textbooks dating back decades, it has been established that beginners have similar neurological adaptations to weight training with light weights and heavy weights. Hypertrophy usually isn't even a major factor for three months into weight training. This study was performed for only 10 weeks. In essence, regardless of the weight training system, method, or principles adhered to, the results would be the same.
Get Super Strong and Become a Pro?
Straight limit strength training is not a one-way ticket to win the Olympia. But there is clearly a relationship between muscle size and strength. Limit strength is your base and must continually be increased to maximize muscularity. More limit strength even equates to better performance on "pump" exercises. For example, a 400-pound bench presser will do more on the pec deck than a 200-pound bencher. Furthermore, he will use a hell of a lot more weight on high-rep pressing sets.
What about Pre-Exhaust Training?
Logically, pre-exhaust training would not be the best choice for getting big!
Let's turn to our brothers in the lab and see what science has to say.
First, let's define our terms. "Pre-Exhaust Training" consists of using a single-joint "isolation" movement to failure before performing a heavier multi-joint "compound" movement. A practical example would be leg extensions before front squats (for the quadriceps) or cable flyes before the bench press (for the chest).
This technique was popularized by Arnold Schwarzenegger in the movie Pumping Iron. If you watched it, you'll remember Arnold performing leg extensions before squats. The idea behind pre-exhaustion training can be summed up thusly: when you fatigue the prime mover muscle with an isolation exercise prior to a heavier compound movement, you will lead to greater muscle fiber recruitment because muscular fatigue will set in before neurological fatigue.
Compound movements require a far greater degree of neuromuscular activity than single joint movements do. Some experts theorize that you'll get the best of both worlds by inserting pre-exhaustion training in your repertoire, as you'll recruit more muscle fibers, which will ultimately lead to much greater muscle growth.
In addition, some prominent coaches and trainers believe pre-exhaustion training is friendlier on the joints. The idea is, as muscular fatigue sets in, prior to training heavy compound movements, these movements can now be trained using lighter loads, yet still yield hypertrophic benefits.
Great in theory, but false in real-world application!
One 2003 study in the Journal of Strength and Conditioning Research conducted on 17 men showed the effect of pre-exhaustion training on lower-extremity muscle activation during the leg press. Prior to performing the leg press exercise, subjects performed a 10-repetition maximum in the leg extension, followed by a 10-repetition maximum in the leg press.
Muscle activation was measured using EMG (electrical activity of the muscle), which showed that activity of the quadriceps, or target muscle, was significantly less when subjects were pre-exhausted. The measurement of the muscle-building effect of an exercise requires more than an EMG reading, but the subjects were able to complete more repetitions and use more weight on the leg press when not in a pre-exhausted state.
The result? The conclusion of this study counter-indicated what many bodybuilders had come to believe. Pre-exhaustion training actually had a disadvantageous effect on performance because of decreased muscular activity and reduced strength when performing core lifts, which after all, are the core of our training.
A 2007 study in Brazil titled "Effects of exercise order on upper-body muscle activation and exercise performance," produced the same conclusion. The study, which also utilized EMG, involved performing repetitions on the machine pec deck, prior to the bench press in a pre-exhaust style.
The study showed that the muscles of the chest were not more efficiently recruited as EMG signals confirmed. The only muscle that had a higher EMG during the bench press was the triceps, and this was simply because the chest was fatigued and motor units from the pectoralis region could not be as effectively recruited. This study concluded that if you want to get better at a particular exercise, perform it first in the training session.
Pre-exhaustion training will not lead to greater muscle fiber recruitment or greater joint safety for that matter. This is due to the fact that muscles which are normally used as prime movers during a compound movement are fatigued, which alters the motor pattern of the compound movement, resulting in less efficient and even unsafe technical execution of compound lifting movements.
Next time someone preaches the gospel of pre-exhaust training for getting big and strong, tell them to take their "bro's science" to a more gullible audience.