Why is it that someone can compete in the same weight class their entire career as an elite weightlifter, yet still continue to lift more weight each year?
Similarly, why is someone able to lift more weight 4 weeks after the first time they picked up a weight in the gym, yet they haven’t gained much if any, body mass?
The answer lies predominantly in the neuromuscular system. More specifically in the series of adaptations that occur in the neuromuscular system in response to resistance training. These adaptations are directly related to the coordination of a large number of components that govern the function of our neuromuscular system. While there are a series of adaptations that happen outside of just the neuromuscular system (which will cover in other articles), today we want to focus on this very large component.
Ever heard the saying practice makes perfect? When looking at improvements in strength training, this adage is no different. When we practice acts of physical strength we get better at performing them. However, the reason why we get better at them is not quite what most people assume.
As we hinted at in the first two examples, a large reason for increases in strength throughout someone’s lifespan (regardless of how much experience they have with training) is simply the co-ordination of their neuromuscular system. Certainly, the actual size of the muscles contributes to the increases in strength. However, what research has shown is that over the long term, factors that regulate the specific ability of the body to exert force in the manner that it is being practiced is what governs our strength (These factors include the neuromuscular system, as well as things such as fibre type shifts and endocrine responses).
Over time the body is very specific around how it will adapt. We mention this because it is important to remember that when it comes to strength training and the general benefits it affords follows a curve of diminishing returns. An example where this plays out would be in an elite sprinter who may not experience benefits in their ability to apply force into the ground (i.e. get faster) when increasing their One Repetition Max Deadlift beyond 2X bodyweight. This example factors in the difference in performance requirements between sprinting and weightlifting i.e. speed of contraction & time to produce force. These different factors require different mechanisms (both neural and muscular to produce the force required). This is important to remember because when seeking a certain result, we have to remember that strength training is fairly task-specific. However, there is still a litany of general benefits to strength training for the average person (particularly those without much or any experience in it).
For the most part, the specificity principle of strength adaptations applies to those who are looking to achieve a specific outcome with their performance. If we take rehab for example, we can notice just how important it is to make sure the rehab that is being performed is not only challenging enough for the person at this point in time, but also specific enough to work towards matching the demands of the activity they want to get back too (this is a big part of the reason why following a generalised protocol alone rarely produces the ideal result desired). Using the example of hiking, a large number of people will experience some form of knee pain during this activity at some stage. The most common rehab for this is to rest until the pain goes down and then perform some very basic isolated strengthening exercises, such as wall sits. Can you see the problem? This is nothing like hiking. Not only is the body constantly moving when hiking but it also faces stresses far greater than simply supporting your body weight up against a wall.
What Will I Get Out Of This [Strength Training: The Ultimate Biohack]
The examples above help to highlight the complexity of strength adaptations and showcase the real-world applications of the concepts we’re about to cover. What we want to do is give you a practical understanding of strength & why it is important to you. Not just a series of information that isn’t applicable to you and you’re life. This article series is the real science with real practical applications. Whether you’re someone at the lowest levels of function or someone who is an experienced trainee, learning about the specific science behind the benefits of strength training will allow you to make the most of the extensive list of benefits this form of training can have.
It’s like the ultimate life hack. And best of all it’s 100% free.
It’s a funny thing. When a lot of people talk about strength training, gaining muscle, getting out of pain, getting jacked or anything regarding improving human performance, they seem to disconnect from the complex anatomical structures that make up a human being. A lot of the time people only really think about what they can see on the surface instead of everything that goes on within the body itself. A lot of this is probably due to a lack of understanding, however it is also useful to think of the body in this way, as more of a ‘system’ than a series of component parts.
Yet what we find is that while there are a series of generalised principles that govern the whole system (e.g. SAID Principle), it is incredibly useful to understand the component parts of that system and how they adapt. This is the best way to make sure you account for as many factors as possible and truly appreciate what goes into the result you are working toward.
On that note, to add some clarity to our discussion we will define some of the key components we are going to talk about.
Neural: Relating to a nerve or the nervous system
Neuromuscular system: the network of nerve cells and fibres which transmits nerve impulses between parts of the body. The neuromuscular system is used interchangeably with ‘nervous system’.
Skill: Ability to perform an action with determined results often within a given amount of time, energy, or both.
CNS: The Central Nervous System which consists of the brain and spinal cord.
PNS: The Peripheral Nervous system which consists of the peripheral nerves that stem from spinal cord and brain in order to supply the major organs of the human body.
What Is Happening Physiologically When We Gain Strength?
For this article, we are just going to focus on the neurological adaptations experienced with strength training. The list is extensive, but here are some of the main adaptations.
Increased Neural Drive – Neural drive represents the output of our central motor cortex and brain in response to stimuli. The increase in this drive as a result of strength training can be accounted for by the practice effect. By practicing forceful contractions, the brain begins to strengthen its connections in the motor cortex to become more efficient at recruiting muscle fibres. This represents neuroplasticity at work, where the brain is able to change itself to suit the demands it faces. It is closely related to the increase in motor unit activation that is seen with strength training.
Increased motor unit activation – a motor unit is the nerve cell that originates in the spinal cord, and all the muscle fibres it controls. When a motor unit is activated, all of the muscle fibres controlled by that neuron will contract in an all or nothing fashion. A muscle consists of many different sized motor units that are relative to the amount of effort required to perform the task. To control muscle force production, the motor units will fire at different frequencies to recruit the most appropriate motor units. Strength training has the ability to improve the activation and the firing frequency of these motor units which allows for greater force production, otherwise known as neural drive (i.e. By practicing strength training it becomes easier to recruit larger motor units in a shorter amount of time to produce the amount of force needed).
Neural cross-education – Cross education basically means that by working one side we can experience adaptations on the other side. This has been proven in untrained individuals. The trial showed an increase of 36% of maximum force production for the bicep muscle on the arm that was trained, with a 25% increase occurring on the opposing side that was not trained at all. The result experienced led to the theory of cross-education, which is where the nerves on either side of the spinal cord communicate with each other for more efficient movement.
Synchronization – this refers to the timing of our ability to fire muscle. In muscle cells, an electrical stimulus, known as an action potential is step one in a series of events leading to muscular contraction. In resistance-trained individuals, synchronisation of the motor units is much greater than those of untrained individuals. With frequent resistance training, this synchronisation improves as our body begins to adapt to the frequent intense muscular contraction, thus aiding in overall force production from the muscles.
Increased Reflex Potentiation – This describes our ability to utilise certain reflexes within the muscle that create greater contractions. Through the firing of motor units.
Increased relaxation of antagonistic muscle groups – Another way in which our body regulates its force production is through the contraction of antagonistic muscles during the performance of a particular movement. This is done to regulate control of the movement, both to allow motor tasks to occur (i.e. small motor movements) and to protect the integrity of the muscle. When we resistance train, we teach our body to become more efficient at using the primary muscles that are needed to perform the movement and decrease the activation of antagonistic ones.
Decreased Golgi Tendon Organ Resistance – This is one of the most surprising adaptations to a lot of people and really helps us to highlight the concept that performance training is simply overcoming the limits that our body places upon itself. Our Golgi Tendon Organ exists in the tendons of our muscles, being incredibly responsive to contraction of the muscle and subsequent force production. The organ creates a negative feedback loop through a neural circuit that ultimately regulates muscle tension by decreasing the activation of the muscle when exceptionally large forces are generated. This is done in order to protect the structural integrity of the muscle itself. When we resistance train we expose our body to ‘exceptionally large forces’ and begin to convince our nervous system that we can handle them. Over time this has the effect of lowering the regulation the Golgi Tendon Organ has on our force production.
Strength is a skill
“Elite Performance is simply a lack of inhibition”
This concept is probably one of the biggest paradigm shifts for most people who get into resistance training.
Strength as a skill was popularised by Pavel Tstatouline however, it is something that has been known for years. What most people think of as brute strength, is actually a series of well co-ordinated systems within the human body all operating in sync to produce a desired result. If we take the example of the first man to ever reach 1000 pounds on the deadlift we can see this concept of strength as a skill playing out. His body requires a heap of co-ordination to pull off the feat of lifting 1000 pounds, co-ordination which came about from years of practice on the deadlift. Sure he was hugely muscular, however, he also had years of specific training on that exact lift. Years of adapting to all of the physiological requirements of that lift. From the grip strength required, to the generation of intraabdominal pressure and stability of his muscles at the angles of the lift, to the control of blood pressure and endocrine response required. These are all highly specific adaptations to that lift itself. If he had of tried to do something very similar to the deadlift, such as a squat, at anywhere close to that much weight at the same time he wouldn’t have been able to because it is a different skill that requires different body positions and physiological demands [See his training journal approaching this lift]. And that’s for a skill that is very similar to deadlifting. If he had’ve applied his deadlift training to something such as a max jump he would’ve likely been nowhere near elite performance, simply due to the difference in requirements for the two activities. Excluding his huge bodyweight as a factor, the main limiter would likely be the difference in muscle contraction speed. For a max deadlift, the speed of movement produced by muscular contraction can be lower than 0.5 m/s (most likely in the 0.2-0.3 range for Bolton). For a max jump the speed of movement can be in excess of 1.3 m/s.
A Lack of Inhibition
If you’ve never heard of the concept of limit strength, this amazing BBC article will be the only introduction you need. Essentially we are much stronger and more capable than we can even comprehend. Any form of physical exertion that we undergo is only a fraction of what we’re truly capable of. Some people come closer to what they truly can do than others, however, our body places regulations on us. Most commonly this regulation comes in the form of pain (e.g. Strech too far and it hurts, push too hard on an exercise and the body sends a pain signal. We all know what it feels like when we do too much intense exercise).
However, there are a whole host of mechanisms that our body uses to regulate us. From trainable components of the muscle fibre such as the Golgi-Tendon Organ, to the constant state of energy conservation our body is in. The human system is in a constant state of flux and every adaptation it undergoes is predominantly focused on maximising it’s survival. An example of this is the muscle atrophy phenomenon seen in astronauts when muscles aren’t used as normal.
In the case of strength, it is usually a feeling of weakness or inability to actually perform the task (e.g. being unable to pick up a heavy object). Your body is smarter than your conscious mind and will do anything it can to make sure that it’s protected. Why risk hurting itself to satisfy the demands of your ego? This feeling of weakness is what we overcome with regular strength training, as we undergo the various neurological adaptations described above. Yet we can move closer to our ultimate potential by making sure conditions are right. Optimal Arousal is one example of this, which basically means that you want to be in the optimal state to perform. By using certain triggers such as music and positive focus, you can begin to upregulate the bodies hormonal responses and create a more energetic state that is conducive to performance. This is part of the purpose of a warm-up. Another interesting aside on this comes from an experiment done with shouting. In the study, participants were shown to increase their maximal force production when shouting during the test (a maximal handgrip test). This is another example that highlights the neurological contribution to strength, as well as showcasing the limitations that our body places on itself. While we don’t usually advise shouting, what we feel it represents is the importance of being in an aroused, sympathetic state when strength performance is required.
More on Limit strength– If you want to dive deep into the limits of human beings & this quote “Performance at the elite level is more about the inhibition of the inbuilt safety mechanisms of the human body, than it is the physical change to the structure” then this answer will give you some more context.
The Central Governer Model Of Fatigue
Remember when we talked about our bodies desire for energy conservation and survival. Well, the Central Governer Model looks at the concept in further detail. It essentially states that our brain will regulate our overall performance due to a large variety of factors While this model typically applies to endurance training & physical exertion of the cardiovascular system, we see the same concept applying to strength & resistance training. It gives us a useful gauge of the limiters on our performance and further hammers home the point the elite performance is simply a lack of inhibition.
What Is Fatigue
Have you ever had that feeling that you just don’t feel strong on certain days? You feel flat all day long and things that normally seem easy become a massive effort. If you go to the gym regularly you definitely will know what we’re talking about. Anecdotally reports have suggested that max strength can fluctuate by 10-20% on any given day based on fatigue (this article showcases some hypothetical examples of this). This is the same for rehab. Some days pain may be significantly greater than others. Overall balance and sense of control might be down. This is completely normal and part of the natural course of our bodies constant adaptation.
What this feeling usually is describing is something that we call central fatigue. This is directly related to our neuromuscular system & in particular the balance of our neurotransmitters that allow for the regulation of muscular contraction. Our body will regulate itself in order to preserve homeostasis and ensure the safety of its systems. It is closely related to muscle fatigue which is mainly associated with the presence of waste and by-products as a result of exertion in the muscle. These forms of fatigue are another way in which regulation occurs within our body. There are a whole host of things that are associated with these forms of fatigue ranging from training response, overtraining and increased intensity, poor diet, lack of sleep and improper recovery just to name a few.
Essentially, fatigue comes about because our body is in a state where it feels threatened. It may be low on resources or not have recovered completely. This isn’t always a bad thing, as a large part of training is forcing our body to adapt. The key is to recognise that fatigue is telling us something. This is important to take note of, as sometimes you might need to take it easy. This is where the habit of consistency becomes so incredibly important to remember. Something is better than nothing and knowing when to push and when to hold back will do a world of good when it comes to health over your lifetime.
Why does this actually matter for me?
Applying this to the rehab trainee. So why have we gone this deep into the neural component and inhibition anyway? It’s because we want to make it as clear as possible for you to understand what the doctor/ physio is actually talking about when they tell you that you need to get stronger. We want you to realise how many different things go into it, along with all the aspects that can be covered to achieve the goal of ‘getting stronger’. To put it simply, just getting stronger may not actually be what you need. You might simply need to improve your stability and general muscle tone. While these things typically result in an improvement of strength across the whole body, what we find is that if someone focuses solely on the strength of an individual muscle (e.g. the quads for knee pain), their stability doesn’t actually improve. This sometimes leaves the person feeling worse than when they started, as they weren’t able to add strength in the place that they needed it. This is a big reason why we don’t like to use machines. Proper strength training requires strength in the whole body, along with the ability to control the body and the loads it is using. When machines are used, we take out the components of the rest of the body and this allow weak areas to continue to stay weak. We certainly don’t think that machines are bad (using them time to time), however, they should only be a part of the overall strength program, particularly when rehab is in question. Essentially it all boils down to our focus on the overall movement of the person in front of us. This is how our pursuit of strength is different to most other rehab providers.
This is important to be aware of, because a lot of what someone says when they suggest that gaining strength will be of benefit could be actually related to neural factors. Take for example a doctor or surgeon suggesting that you need to get stronger. What we typically find is that they are actually referring to an increase in stability. Sure strength and size of a muscle are a consequence of this however, they can’t be the focus. Doing so would neglect the most important element that is contributing to the pain in the first place. That’s why it’s important to define precisely what the strength is for. We can take care of the rest. If someone took heed of the advice from the doctor they could easily jump on to Google and search for strength programs. What they would probably find would be a confusing mess of programming and tips that simply aren’t appropriate for the specific goal they’re trying to achieve.
The neural component of strength helps us to realise that we are capable of far more than we might think
If you’re rehabbing or are in pain and have been told you need to increase your strength, firstly understanding why strength is so important will help you tremendously. Here are our top 3 reasons:
- Strength train for the benefits it offers. Remember that exercise is medicine. We are doing it because of the positive physiological responses it has within our body. Don’t worry about satisfying your ego. The number on the bar doesn’t always matter. As long as your seeing the results you want (i.e. looking better, moving better, feeling better), then things are going as planned.
- You are capable of more than you know. To achieve what you previously thought was impossible, all you need to do is practice!
- Strength is the fountain of youth. Our body is an adaptive machine. It is constantly adapting to the demands it faces. Years of medicine has shown us that when it is challenged, our body begins to adapt in a way that improves our health. The opposite happens when don’t challenge ourselves. We begin to maladapt and encounter what is known as sickness and disease. More on the extensive benefits here.
- Strength training is incredibly beneficial
- Strength adaptations become more and more specific as we progress further and begin to desire a certain result (e.g. achieving a certain goal)
- Specificity applies to rehab. If the rehab you are doing is not close to the demands you are going to be facing when you return to the activity you want to get back to, then it is not rehab & it misses out on the specificity principle. It needs to be challenging enough for the person at that time, but also specific to the task they’re trying to perform
- Our body will regulate us constantly. This is why the use it or lose it phenomenon is so important for general health. Well designed intelligent strength training helps us to overcome these limits so that we can maintain good health for as long as possible.
- The easiest way to maintain strength over the long term is to have a meaningful activity that requires strength to be able to perform it as well as you would like. This could be participation in any form of sport, recreational activity or simply just strength training itself. The key to connecting your strength training to your activity is to train with the focus of improving your performance and minimising pain/ injury. When focusing on these things the benefits that most people seek strength training for will come (e.g. muscle size, strength, overall body composition). Setting a goal can really help with the enjoyment aspect.
- Remember that pain is a useful signal from our body. Without it, our structure would likely collapse as we would continue damaging what hurts and maladapting to our current way of doing things (or not doing anything at all). What we find is that pain is often our body telling us that we lack the strength in a certain area of our body to do what we’re asking of it. This lack of strength is an unfortunate consequence of a sedentary lifestyle. The remedy for this becomes intelligent strength training that causes our body to undergo favourable adaptations on a regular basis.
- Aim for optimal arousal. A lot of people find that when it comes to strength performance being in the right mindset, which is positive can have a big difference. Music can help a lot with this.
- Myth: If I’m lifting less weight, then I have lost muscle. This is what understanding the neural component of strength helps us to realise. Just because we are lifting less weight on a certain lift in the gym, doesn’t mean we have lost muscle mass. Remember that strength is a skill, so usually, this decrease in ‘strength’ is simply neural. This is a big concern for a lot of people who don’t perform a certain lift for a while, then freak out that they have lost size.
- Improving the neural component of strength is simply practising moving your body under loading and testing what it’s capable of doing.
- In a rehab context, what is often prescribed as a need to improve strength is actually a need to improve our stability and overall co-ordination. That’s where finding something that is fun and empowering comes into play, as strength then serves as a means to a sustainable end.
- Central Governer Model
- Barbell Medicine, the benefits of strength training (Osteoarthritis as the example)
- Benefits of Strength Training on Quality of Life: Older Adults
- Resistance Training & Elite Athletes (Full paper)
- Task Specificity of Strength Training
- Generalised List of the benefits of resistance training
- Henneman’s size principle
- Empowerment – MTP’s Core principle & The Power Of Goal Setting