Strength training and nervous system development

Strength training makes you stronger through more than just muscle growth. A very large share of your progress comes from the nervous system: your brain, nerve cells and muscle fibers learn to work together faster and more effectively.

This goes a long way toward explaining why beginners can gain strength rapidly in the first few months, even when they see little change in the mirror. Your body is learning to exert itself. More precisely, it is learning to activate more muscle fibers at the right moment.

Why does strength training build strength before muscle mass?

Muscle mass matters when developing strength, but it is not the whole story. A muscle contains many motor units. A motor unit consists of one nerve cell and the muscle fibers it controls. When the nerve cell sends more impulses to the muscle, the muscle can generate greater tension.

Tug-of-war offers a simple example. If 10 men pull on a rope at different times, some of their force is wasted. If they pull at the same moment and in the same rhythm, the result is very different. Something similar happens in your muscles. Training teaches motor units to work together.

In an untrained person, not all muscle fibers activate immediately and simultaneously. The illustration in the original text is a good one: it is not a case of 122 muscle fibers working in the first half-second, another 78 muscle fibers contracting in the second half-second, and then a few more joining in. We do not notice these differences in everyday life, but measuring instruments can detect them.

So what actually happens? Training improves motor unit recruitment, or the activation of motor units. Their firing rate also improves. The higher a motor neuron’s firing rate, the greater the force its motor unit generates.

How does strength training teach the nervous system?

Nervous system adaptations are especially important when lifting heavy weights for short sets. When resistance is low, low-threshold, slow-twitch motor units do much of the work. They fire at a fairly low rate and generate less muscle tension.

As the weight increases, voluntary effort must increase. Additional motor units are then recruited, and the firing rate of those already active increases. Activating large nerve cells requires a stimulus that produces a firing rate of at least 30 Hz. Small motor units fire at 0 – 30 Hz.

For beginners, the problem is simple: you may not know how to exert maximal effort. This is not due to laziness, but because your nervous system has not yet learned to activate all the necessary muscle fibers at once. If a muscle had 100 fibers, perhaps only 60 fibers would be working effectively when you first start training. Over time, more join in.

This is why strength often increases rapidly at first. Later, progress slows because activating additional motor units becomes increasingly difficult. Technique, recovery, your training plan and how intelligently you increase your training load then begin to matter more.

Firing rate and voluntary effort

The more impulses a nerve cell sends to a muscle fiber per unit of time, the greater the tension the muscle can generate. This is more than theory. When a squat, press or deadlift demands serious effort, your nervous system has to send a much clearer signal to the muscle.

The type of training also comes into play here. Shorter sets with heavier weights place greater emphasis on developing this ability of the nervous system. Longer sets also work, but their main effects shift more toward metabolic adaptations in the muscle and hypertrophy.

Strength training and rep ranges in practice

Rep ranges are not magic, but they shape the effects of training. If your goal is purely maximal strength, your plan will look different from one designed to build more muscle mass or local muscular endurance.

• Training in the 1 5 rep range with weights of 85 100% produces adaptations largely through neural mechanisms. Maximal strength, speed and power improve, while muscle hypertrophy is more modest.
• Training in the 6 8 rep range with weights of 75 85% develops both neural and metabolic mechanisms. This is why 6 8 reps are often associated with gains in both strength and muscle mass.
• Training in the 9 12 rep range with weights of 70 75% still produces a mix of effects, but the emphasis shifts more toward muscle hypertrophy. Strength improves, though usually to a lesser extent.
• Training in the 13 20+ rep range with weights of 60 70% develops local muscular endurance to a greater extent, as well as muscle hypertrophy. Gains in maximal strength are more modest.

This does not mean that one range is always better. It depends on your goal. A powerlifter may do a lot of work in the 1 – 6 rep range, but their training also includes assistance exercises with a higher rep count. A bodybuilder may perform longer sets, but still benefits from periods of lifting heavier weights.

For an athlete focused purely on strength and explosive power, much of their progress often comes from improvements in nervous system function. Still, metabolic changes, protein synthesis and myofibrillar hypertrophy also play a part.

Strength training in practice: what should you watch for?

If you want to get stronger, look beyond muscle size. Pay attention to whether your technique holds up, whether you can really push yourself during your sets and whether the weights you lift increase over time. Strength does not come from muscle cross-sectional area alone.

Several factors determine how much strength a muscle can produce: intramuscular coordination, intermuscular coordination, the angle at which force is applied, muscle length or joint angle, the muscle’s anatomical and physiological cross-sectional areas, and its fiber composition. In other words, strength is the combined result of your nervous system, muscles and technique.

In practice, maintain sound technique in your main exercises, incorporate heavier sets periodically and do not assume that every workout has to end in total exhaustion. Heavy weights train your nervous system, but making maximal efforts too often can derail recovery.

Honestly, this is one area where patience counts. Progress is fast at first. Later, you need to pay more attention to the details: your warm-up, rest intervals, the quality of your sets and whether every heavy rep looks like a practiced movement rather than something you just managed to get through.

FAQ: strength training and the nervous system

Can strength training make you stronger without substantial muscle growth?

Yes. Especially when you first start training, strength can increase faster than muscle mass. This is due to neural adaptation: your body learns to use its existing muscle fibers more effectively and in better synchrony.

Why are 1 – 6 reps associated with strength?

Performing 1 – 6 reps usually means lifting heavier weights and exerting greater voluntary effort. This forces your nervous system to recruit more motor units and improves how they work together.

Are longer sets useless for strength?

No. Longer sets support muscle growth and endurance and can also improve strength. Heavier weights and shorter sets simply have a more direct effect on developing maximal strength.

Note: Some of the ideas in the original text came from a forum reply, so the same topic is presented here in a clearer sequence.

Author: Janar Rückenberg

Source:Turg.Fitness.ee

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