Does the nervous system affect how strong I am?

Yes, substantially. A large share of early strength gain comes from neural change rather than bigger muscle: Better motor unit recruitment, higher firing rates, improved coordination between muscles, and reduced protective inhibition. That is why you can become markedly stronger before your body looks any different.

What changes in the first weeks

• Recruitment: You become able to call on more of the available motor units, including the high-threshold ones that produce the most force.
• Rate coding: The nervous system fires those units faster, which raises force output and how quickly it arrives.
• Coordination: Prime movers, synergists, and stabilisers time themselves better, so less force is wasted fighting your own body.
• Reduced inhibition: Protective mechanisms that limit output relax as a movement becomes familiar and feels safe.

Why this explains common experiences

It explains why a beginner can add 20 kg to a squat in six weeks without gaining muscle, why strength is highly specific to the exact lift you practise, and why a movement you have not done in months feels weak even though you have not lost tissue. It also explains why practising a lift often, rather than simply training the muscles involved, is such an effective way to get stronger.

How to train the neural side deliberately

Heavy loads in low rep ranges, performed with full recovery and good technique, are the main tool. Fast, intentional effort with lighter loads develops rate of force development. Frequency matters too, because skill improves with practice: Two or three exposures a week to a lift beats one. This is the reasoning behind the approach in Maximum Strength Development.

The trade-off

Neural work is demanding to recover from even when the volume looks small, because heavy singles and maximal-intent efforts fatigue the nervous system rather than just the muscle. That is why maximal work is organised into blocks rather than pushed every week, and why sleep quality has such a visible effect on how strong you feel.

For the wider picture of how the nervous system shapes performance beyond strength, see The Nervous System and Athletic Performance.