The recent science seems to suggest that muscle fatigue is the primary stimulus for muscle growth. reputable sources like strongerbyscience.com and even Paul Wade’s C-Mass, point to muscle fatigue as the primary reason why a muscle grows.
The evidence is compelling. It seems that as long as you bring a muscle to a high state of fatigue then it will grow and variables like weight, sets, and reps are only secondary considerations.
I don’t doubt that muscle fatigue is important for muscle growth, but I’m starting to wonder if it’s a misdirected notion. Working out to create fatigue isn’t difficult, but sometimes reaching a state of fatigue isn’t enough. If getting tired and worn out was enough then that should make most anyone who works out much bigger. While I don’t doubt that fatigue is an important part of the process, maybe there’s more to the story.
The muscle fatigue theory states that when you work your muscles to a high level of fatigue you use up a lot of the “biomechanical energy” within the muscle cells. When your muscles recover they pack a little more of that chemical energy in the cell, sort of like stuffing more acid and water into a battery. This is what makes your muscles a little bit bigger and repeating the process many times over is how guys go from scrawny to brawny.
So it looks like we get bigger due to fatigue, but there’s more to the story. It’s not so much about making the muscle tired, but placing a progressive energy demand on the muscle that’s important. Your muscles don’t get bigger because you make them tired, they get bigger because you ask them to produce more energy. While doing so does create a lot of fatigue, we must be careful not to mistake the result of the cause of muscle growth for the actual cause.
Instead of seeking muscle fatigue in your workouts, try asking your muscles to produce more energy. You can do this through either increasing tension or time. Adding reps, or resistance are both good ways to make the muscle produce more energy. Even adjusting your technique, like in Convict Conditioning can make your muscle produce more energy. Seeking energy production is more direct and will tell your muscles to grow with a more reliability than just trying to run yourself into the ground each workout.