In the last post I asked Why train your nerves? It was a precursor to explaining the value of a healthy and strong nervous system to athletic performance.
In fact it is little known that the reason sedentary people improve so much when they begin exercising is because their nervous system adapts very quickly. The reason for the inevitable plateau is that the rest of the body takes much longer to adapt. So improvements then reflect the normal pace of change within the body.
Nerves adapt quickly
The specific reason for such vast improvements when people return to activity is pretty much down to nerves triggering muscles. Muscles, bones, ligaments and nerves don’t grow particularly fast so of course improvements couldn’t come from new growth. Instead muscle output and thus strength, endurance and other athletic measures depend on good coordination of all the systems involved. So the big improvements come from the coordination of muscles and at a much smaller level muscles are broken down into groups of muscle cells controlled by motor units which are groups of nerves that tell the muscle cells when to fire.
Despite how it looks and feels it is rare for the whole of a muscle to contract (fire) at once. The reality is that each unit of muscle cells fires at a specific time aiming to produce a pattern of firing that leads to the desired result. Muscles that haven’t been used often therefore become lax at achieving and maintaining the specific firing patterns that are required. They know what to do but are out of practise. We can all relate to that. Specifically they are unable to achieve the exact pattern of firing required but they also tire sooner. They seem to run out of energy.
Lack of nerve
The evidence is that energy for the muscle to move is still there and if triggered it will move. The problem lies with the trigger system. The nerves are simply not able to trigger the muscles for long enough.
I studied sports science at university yet this explanation wasn’t part of my course. I found it delving deeper into books I found. The single point of failure was always assumed to be the muscle even though all the evidence pointed elsewhere.
So of course I’ve been waiting to take this insight further and share. That time has now come.
Muscle output: Is it neural?
An experiment we undertook during my studies at Loughborough taught me early on that it wasn’t muscle fatigue or presence of lactic acid that limited performance despite common knowledge saying otherwise.
We completed some experiments with repeated sprints and measured lactic acid and muscle output from repeated 30 second sprints on a stationary bike. Each participant was a sports science student, fitness wasn’t tested but assumed to be normal or above average.
What has always stuck in my mind was that the participants could always produce more power and muscle output in the second sprint compared to the first. This defies the logic that Lactic acid hinders performance because the second sprint always occurred with much more Lactic acid travelling through the individuals system. So, at least in this experiment Lactic Acid concentration didn’t impede exercise power output.
I was weight training from an early age so I was familiar with having more strength and power in my second set of work than my first and this experiment opened my eyes as to why. I had heard before that Lactic acid doesn’t have the impact that it’s famed for. Not in sprinting and power activities at least.
So I had always wondered if the nervous system had a greater role to play. Over time I have found articles and experiments indicating that the ability of nerves to do their job is the defining factor in performing a skill assuming someone is proficient.
This is based on these three statements:
- Do muscles fatigue as quickly as thought?
- If not Something else is the weakpoint. What is it?
- Does the ability of nerves to trigger muscle activity determine muscle output?
The problem is that I found much of this research before I knew about the internet. So my challenge now is to ask these questions again and see what I find.
- A Brain Circuit Underpinning Locomotor Speed Control By exploiting the relative accessibility of adult zebrafish, combined with a broad range of techniques, the researchers can now reveal two brain circuits that encode the start, duration and sudden change in locomotor speed.