When you lift weights, your muscles get bigger, and that makes you stronger—it’s science. But many people don’t realize there are many other ways that strength gains occur. For example, a massive portion of strength development happens via the nervous system.
This week The Movement will focus on the neuromuscular gains that help you add more plates to the bar.
How the Brain Controls the Muscle
A motor unit is a single neuron that connects with the muscle fibers. Each muscle has 100’s-1000’s of motor units. A motor unit can contract thousands of muscle fibers in bigger muscles, but in muscles that need fine control (e.g.- the eye), one neuron may control just a few muscle fibers.
Nervous System Strength Adaptations:
1. Increased Motor Units & Synchronization
The brain’s ability to activate more motor units at the right time improves with training. New weightlifters often see a big bump in strength without adding any new muscle. The body is learning to activate the muscle fibers it already has.
2. Increased Motor Unit Firing Rate
Not only does the brain learn to fire more motor units, but it also increases the rate at which those motor units are activated. This mechanism is called rate coding and improves the force and the speed at which the muscles can generate force
3. Increased Recruitment of High-Threshold Motor Units
When the brain initiates a muscle contraction, it starts with the smaller motor units (low threshold) and progressively activates the larger ones (high-threshold) as needed. With training, the nervous system better coordinates the low and high threshold motor units. This leaves more muscle in the tank for heavier weights.
4. Improved Motor-Unit Coordination
Important for strength and power is the ability to use the elastic parts of the muscle to create movement (like a rubber band). With training, the brain learns to inhibit the protective mechanism in place in order to effectively use the stretch reflex of the muscle.
Below is a cool chart that shows what adaptations occur best at certain loads:
Source: Periodization Training for Sports-3RD Edition by Tudor Bompa & Carlo Buzzichelli
I hope that all of this made your brain stronger, now keep it in mind as you work on your muscles.