What is pre-fatiguing a muscle and can it boost muscle hypertrophy more than traditional training? We all want to maximize our training & get the most out of the time we spend exercising and that includes strength training. But, after a period of progress, muscle growth can sometimes stall. That’s when you have to throw out all the stops and use more advanced training techniques to jumpstart growth again. One technique that some people use in the quest to break a plateau is pre-fatigue or pre-exhaust training.
What is Pre-Fatigue Training?
Pre-fatigue is a training approach where you tire out a muscle group using a single-joint exercise before doing a compound exercise that works the same muscle group. Pre-fatiguing a muscle goes against traditional thinking. Most experts tell you should do the most important exercises first, the compound moves. These are the movements that work multiple muscle groups, so start with them before doing an exercise that works a single muscle group. This ensures your muscles aren’t fatigued when you do the most important and time-efficient, compound exercises.
However, pre-fatigue pre-exhaust training takes a different approach. Rather than performing a compound exercise first, you, instead, do an isolation exercise. For example, start with a few sets of leg extensions first to exhaust the quads. Once your quads are fatigued from the isolation exercise, shift to a compound exercise for the quads, like squats.
Why would you want to train this way? Once you’ve exhausted the quads. The other muscles that work when you squat, like the glutes and hamstrings, have to work even harder because the quads can’t chip in as much because they’re exhausted! The other muscles, in this case, the hamstrings and glutes, have to make up for the quad fatigue by contracting with more force. Therefore, you activate more hamstring and glute muscle fibers than if you haven’t exhausted the quads beforehand.
You can use a pre-fatigue or pre-exhaust approach for almost any muscle group. Examples include:
Triceps
Isolation exercise: Triceps Kickback
Compound exercise: Triceps Dip
Shoulders
Isolation exercise: Lateral Raise
Compound exercise: Barbell Shoulder Press
Hamstrings
Isolation exercise: Leg curls on a stability ball
Compound: Lunges
Chest
Isolation exercise: Chest flys
Compound exercise: Chest press
How many sets should you do? Choose a wait for the isolation exercise that you can lift 8 to 12 times. Do 3 sets of the isolation movement. Rest for a few minutes and then move to the compound movement.
What Science Says about Pre-Fatigue Training
How effective is this advanced training technique? It makes sense from a logical standpoint, but not all studies show that pre-fatigue training is better than standard training for building muscle size. A 2003 study looked at this issue. Researchers asked 17 men to do a set of knee extensions using a resistance corresponding to their 1- rep max. This was followed by a set of leg presses. Knee extensions are an isolation movement and leg presses are a compound exercise.
The researchers used EMG to measure activation of the hamstring muscles and glutes. They also recorded the number of repetitions on the leg press both with pre-fatigue (performing the knee extensions beforehand) and without. The results? The participants performed fewer repetitions on the leg presses when they were pre-fatigued. Also, EMG showed less activation of the hamstring muscles during the presses.
Another study that looked at pre-fatigue training of the upper body. In this study, participants performed an isolation movement for the chest muscles – the machine pec deck – to pre-fatigue the muscles. This was followed by bench press, a compound exercise that works the chest. The study also measured muscle activation using EMG.
The results? The muscles of the chest weren’t activated as much during the compound exercise when the participants did the isolation exercise beforehand. However, the triceps WERE activated more since they had to work harder to compensate for the fatigued chest muscles. So, if you’re trying to give your triceps a push, this combination may help. But it won’t improve performance on the larger chest muscles since they’re already fatigued by the pre-exhaust, isolation exercise.
Another potential drawback to this approach is fatiguing a muscle that you use in the compound move that follows may change your form and movement pattern in such a way that it leads to injury. You’re essentially knocking out one muscle that you normally use to do a particular exercise. Other muscles have to overcompensate You could end up with a strained muscle.
When Should You Pre-Fatigue?
Although a pre-fatigue approach to muscle hypertrophy sounds effective in theory, studies don’t show that it’s better than traditional sets. The drawback is pre-fatiguing could reduce the number of reps you’re able to do on the compound exercise, the most important exercise since it works the most muscle groups. So, don’t use it for the bulk of your training.
Where it might be beneficial is as a plateau buster. Our muscles adapt to the same repetitive way of training and stop growing. You can always alter training variables such as the resistance you use, the training volume, number of reps, the tempo, number of sets, the rest period between sets, exercise order, and training frequency. Yet sometimes you need to approach your training in a way your muscles aren’t accustomed to mix things up. Pre-fatigue training is a wake-up call to your muscles because it’s a training approach they’re not used to. Therefore, it could help you break out of a stubborn plateau and jumpstart your gains. But, when you compare pre-fatigue training to traditional training approaches, there’s little evidence that it’s better for muscle growth.
The Bottom Line
Pre-fatigue training is a different approach to training and sometimes your muscles need a novel stimulus. Don’t make it the bulk of your training but use it as an advanced training technique when you reach a plateau. It’s one of many advanced training techniques you can use when your muscles need a surprise. Others include partials, forced reps, negatives, rest-pause, and drop sets. So, there’s no reason for your training to ever become stagnant.
References:
J Strength Cond Res. 2003 May;17(2):411-6.
J Strength Cond Res. 2010 Apr;24(4):1043-51. doi: 10.1519/JSC.0b013e3181d3e993.
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