Getting Stronger Is Also a Learning Process
Your muscles matter. So does the nervous system helping them do the work.
By Marie Cole
MCE Journal · Strength & Everyday Movement
The first time you try an unfamiliar strength exercise, there can be a surprising amount of administration.
Where do your feet go? What are your shoulders doing? Why has the instructor mentioned breathing as though that wasn’t already on your schedule?
A few sessions later, you may spend less attention negotiating the movement. The setup feels more familiar. The exercise may feel more controlled. You might be able to produce more force, even without an obvious change in appearance.
Part of the explanation is that strength training involves a nervous system as well as a set of muscles.
Muscle size is only part of strength
Muscles produce force when the nervous system activates them. A motor unit consists of a motor neuron and the muscle fibers it supplies. How these units are recruited and how rapidly they receive signals help shape the force a muscle produces. [1]
Training can change that activity. A review in the European Journal of Applied Physiology describes evidence that neural adaptations contribute to early increases in strength, while also emphasizing that researchers have not fully located or explained all the underlying changes. [1]
The useful point is not that the muscles are irrelevant. It is that an increase in what you can do does not have to be explained entirely by an increase in how large they are.
Researchers have tracked the signals
In a study published in 2019, researchers followed motor-unit activity during four weeks of training involving the muscles that pull the foot upward. Fourteen participants trained, and fourteen served as controls. The researchers observed changes in the recruitment and firing behavior of tracked motor units alongside increased force. [2]
This was a specific laboratory task in recreationally active young men. It does not tell us exactly what will happen to every person doing squats, lifting groceries, or starting a class after forty.
It does show why scientists look beyond muscle size when investigating how strength changes. The instructions reaching the muscle are part of the story.
Notice what the movement is doing
For someone learning an exercise, that offers a more interesting set of things to observe than appearance alone.
Can you remember the setup? Is the movement more consistent? Are you completing the same planned work with better control? Those observations cannot diagnose a neural adaptation, but they can make a training record more useful.
If you already have an exercise you perform comfortably with appropriate guidance, write down the version you used, the resistance, and the repetitions. Add one plain observation about technique. Compare similar sessions over time rather than asking a single day to explain everything.
Keep the comparison honest. A heavier weight moved through a smaller range, with a different technique, is a different task. If you are learning a new movement, a qualified trainer or relevant clinician can help you choose and assess it.
There is more than one way to get better
Muscle growth and neural adaptations can overlap. There is no universal date on which one ends and the other begins, and the contribution of each depends on the person and the training. [1]
You do not need to identify the exact mechanism behind every better session to value it. Becoming more capable at a movement is useful information in its own right.
The mirror cannot tell you everything your body is learning.
RESEARCH SOURCES
[1] Škarabot, J., et al. (2021). The knowns and unknowns of neural adaptations to resistance training. European Journal of Applied Physiology, 121, 675–685. Published online December 23, 2020. DOI: 10.1007/s00421-020-04567-3.
https://pmc.ncbi.nlm.nih.gov/articles/PMC7892509/
[2] Del Vecchio, A., et al. (2019). The increase in muscle force after 4 weeks of strength training is mediated by adaptations in motor unit recruitment and rate coding. The Journal of Physiology, 597(7), 1873–1887. DOI: 10.1113/JP277250.
