When you start a resistance training program, your muscles don’t change much at first but your nervous system does. A new study shows that you may need more than just reps to make your strength training stick—you need to deliberately train to strengthen your nerves.
Before I dive into the fascinating data from a study published in the Journal of Neuroscience—Cortical, corticospinal and reticulospinal contributions to strength training—I'll point out that this study was conducted with macaques, not humans. But, as I will cover later, macaques have a very similar nervous system to humans so this isn’t a big stretch.
It was also a small study that involved only two monkeys, both female. But since the researchers were studying the fundamental features of motor control, they don’t expect any differences in males.
Due to particularities in our nervous system, if we practice deliberately, we can respond quickly and effectively to resistance training.
So with those caveats out of the way, let’s look at the results. This study points to evidence that, due to particularities in our nervous system, if we practice deliberately, we can respond quickly and effectively to resistance training. And that's true even if we don’t see a large amount of muscle growth as soon as we start hitting the gym.
Stronger nerves, not bigger bulk
Sports scientists have known for a while that early increases in strength involve both building new connections and eliciting changes to the existing connections between our brains and our muscles. (We call these "neuromuscular connections.") This process involves bundles of neurons and nerve fibers carrying commands from the brain’s motor cortex through the spinal cord to the muscles more efficiently and effectively. As these motor cortex commands get stronger and faster, the muscles receiving the commands generally respond in kind, giving us a functionally stronger reaction.
To illustrate this, let’s look at learning to do a pull-up. When you first learn a movement like this, we generally focus on something called the principle of specificity. In basic terms, we want to increase the volume of pull-ups you do on a regular basis. That's because every time you pull your body up and pop your chin over that bar, your neuromuscular system gets better at creating the interaction between your motor cortex, muscles, and nerves, optimizing them to become more effective at doing the movement known as the pull-up.
This is most evident when you're learning to do your first pull-up. The difference between doing none and three pull-ups is mostly neuromuscular while the difference between doing four and twenty pull-ups is mostly strength.
Even though researchers have witnessed this many times, the actual mechanics of these changes remain unclear. That's one of the reasons why this particular group of researchers surgically implanted transmitters and electrodes into macaques.
Rest assured—the researchers complied fully with all the regulations for the humane treatment of animals.
The implanted electrodes had a very particular job. They stimulated different sets of monkey nerves while the researchers tracked their changes as the monkeys did their (presumably adorable) strength training workouts.
For their weight training regimen, the researchers prompted the monkeys to exercise by bribing them with treats. (Sounds like a familiar scenario! We humans often do the same thing, just not in the name of science. But I digress.)
Using the treat reward system, the researchers measured which nerves became most activated while they got the macaques to pull a weighted lever with one arm. The measurements were done before, during, and after the workout.
I think it's important to point out that macaques, like other primates (including humans), have two major bundles of nerves that transmit messages from the motor cortex.
The reticulospinal tract is generally believed to direct broad motor skills, controlling locomotion and posture
The corticospinal tract is mostly involved in muscle strength, controlling movements of the limbs and trunk.
The study went on for almost three months. As you may recall from an older Get-Fit Guy article, that's longer than necessary to see gains in muscle size. During that time, the macaques worked out five times a week, with ever-increasing resistance, until they could complete the monkey workout equivalent “to a human doing 50 one-armed pull-ups,” says Isabel Glover, a neuroscientist at the Movement Laboratory at Newcastle University. So these macaques were not fooling around!
While doing this extremely impressive workout, the electrode data indicated stronger and more efficient commands being delivered to the muscles by the reticulospinal tract—an unexpected result. The researchers were expecting to see stronger signals in the corticospinal tract, the ones that have generally been linked to muscle strength.
This surprising finding proved something to the researchers. “Strength isn’t just about muscle mass,” Isabel Glover told The New York Times. “You get stronger because the neural input to your muscles increases.”
“Initial gains are all about strengthening the reticulospinal tract,” Baker added. “Only later do the muscles actually start to grow.”
What does this mean for humans?
Gaining a better understanding of how the nervous systems works in conjunction with strength and muscle control could have medical applications. If physicians can understand the more nuanced parts of how the nervous system changes during exercise, they could use the information to help stroke victims, the chronically ill, and the elderly. But I think there's also a lesson here on how we approach our daily training.
We tend to think that to master a new sport, athletic endeavor, or fancy lift at the gym, we simply need to practice, practice, practice. But given what is being discovered in studies of the nervous system like this one, I think we need to focus on more than just repetition. We need to be deliberate about our practice.
The author of Atomic Habits, James Clear, wrote:
Deliberate practice refers to a special type of practice that is purposeful and systematic. While regular practice might include mindless repetitions, deliberate practice requires focused attention and is conducted with the specific goal of improving performance.
Golfer Ben Hogan is often referred to as having created something called “inventing practice.” He broke the game down into its most fundamental aspects and then tackled the deliberate endeavor of learning to master each of those aspects. This process included not only separating his golf-swing from his follow-through but also breaking down each aspect of the swing itself.
A paper called Digging it out of the Dirt: Ben Hogan, Deliberate Practice and the Secret: A Response to Commentaries argues that Hogan’s success was partly due to “his ability to practice in a deeper cognitive state than his peers,” which I believe directly tapped into his reticulospinal tract.
Let's go back to my pull-up example. It’s not hard to imagine: If you take your time, focus on the job at hand, and focus solely on executing one, two, or three pull-ups a few times per day, you will get better faster. And if you haphazardly do as many pull-ups as possible while thinking about lunch, listening to a podcast, and paying little attention to your form ... well, you may get there eventually, but it will take more time, more pain, and your pull-ups will likely never look graceful.
That's your nervous system at work. This isn’t about muscling through a movement with sheer brute force; this is a methodical and meticulous communication between your motor cortex, nervous system, and muscles.
If you skip deliberate practice, not only do you give your nervous system a raw deal but you also run the risk of developing the wrong muscles for the job. Instead of allowing your brain to connect to the muscles that are key in executing a good pull-up, you force your body to use muscles that it may have better connections to but weren’t meant to be major contributors to that particular movement. And that's where injury and imbalances begin.
So, if you want to get better at a particular exercise or movement in the most efficient way, make sure you give your nervous system the time and attention it needs to do its job before you start relying on your bulging muscles. Trust me, you will get the muscles soon enough and in all the right places.