Taking a small break from our one-leg jumping related articles, I want to divert your attention to one particular topic – the topic of muscular irradiation.
This has been documented sparingly over the years, but not to the extent (at least in terms of making it aware to the vast majority of the targeted public – people interested in sports but also, like I said – injury prevention and just overall health and strength) that I would’ve liked. Now the purpose of this article is to increase the awareness of this muscular irradiation mechanism.
The mechanism of muscular irradiation refers to the ability of a muscle that is performing an action (of any kind – it doesn’t really have to be specifically concentric, isometric or eccentric in nature) to generate more tension by being “innervated” better by the surrounding muscles’ contractions. This is an universally “accepted” rule, where any muscle can generate a better firing potential into another nearby muscle. Despite this, there are three main groups of muscles that seem to give you the best bang for your buck and that, in every individual, seem to provide an immediate boost of strength, power and stability. These three groups of muscles are:
- The glutes;
- The abs;
- The forearms.
To understand this better we need to provide some easy examples. One example would be handshaking. Try to shake a friend’s hand squeezing his hand as strong as you can while keeping the rest of your body relaxed. Basically, only use your hand and forearm muscles (as best as you can) to squeeze his hand. Tell him to remember how strong the squeeze was. Take a ~30s break and now squeeze his hand again. This time, try to really contract your glutes as strong as you can and contract (flatten) the abs as strong as you can, besides squeezing his hand as strong as you can. Basically, you want to tend to a posterior pelvic tilt (by squeezing the abs and the glutes you will naturally tend to get into this position) as you shake your friend’s hand. Now ask him again if your squeeze was stronger this time. Provided you did everything right, he should (and even you should) say the squeeze in the 2nd instance was stronger (sometimes significantly so).
You see, these three muscles – the glutes, the abs and the forearms – tend to give you the best power augmentation results in doing pretty much anything that requires strength. You can try this with pretty much any exercise – try it with squats, try it with deadlifts, try it in a short acceleration of a sprint (this might not be that good of an idea in the later portion of sprints since at that point you might be better off being relaxed rather than maximally tensed). Also, in events regarding stability and balance – you will tend to find that squeezing these three muscles will improve your stabilizing abilities.
In fact – as a sidenote – one interesting thing I’ve found is that you can find out how well someone has glute control if you have them take off their pants while standing (no, not for the purpose you’re thinking at right now). Most people will struggle taking one part of the pants out of their feet while staying on one leg and will lose balance. Yet they usually have better balance on the other leg. This is really in congruence with their strong vs. weak leg correlation, it really is consistent with their take-off in a two-footed jump (with a left-right or right-left plant), it is consistent with how they ride a skateboard, with what leg they kick a soccer ball and so on. What I’ve discovered is that people have a “strong” or “dominant” leg because they have better hip control on that leg (obviously strength matters as well).
For example – a guy that jumps off his left leg the highest trying to dunk with his right hand will tend to have better hip control with his left leg. He will also display better balance on that left leg (including taking his pants off), he will tend to stay on a skateboard in a LR (left foot back) position, will tend to plant LR (left foot first, then rotate and plant the right and jump) off two feet in a jump and will tend to kick with the right leg a soccer ball. So you actually kick the ball with your weak leg. Why? Because the body will gravitate towards being stable in order to generate power. So it chooses to be stable on the stronger left leg and once that stability (and hip control in this specific case) is being felt, then the body is free to exert power kicking the ball with the right leg. Not only that, but the right leg will be more precise because of the superior hip stability in the left leg rather than the right leg itself being precise, something that a lot of people either underrate or don’t understand to begin with.
Now what you need to take away from all this is that in order to generate power, the nervous system has to at least “believe” it is in the right position from a stability standpoint to do so. Try running on ice and see how much power you can generate. Sure, part of that is the lack of friction, but a huge part of that is also because the CNS “shuts down” because it feels the lack of stability. And when the lack of stability is present, then the CNS will lower its power output in order to prevent injury from occurring. Once again, we must marvel before how smart our body is being constructed and how all these elements work together to make sense of our efforts and to balance power production with safety.
Getting back on topic – what you do when you use muscular irradiation by squeezing these 3 muscle groups – the glutes, abs and forearms? You increase body stability (through the isometric tension that you generate in this muscles) and in return, the CNS will increase the power output in your desired move because of this “feeling of safety” that it gets from the mechano and proprio-receptors. The feedback that the CNS is receiving is “the body is ready to produce power and is in a state of stability, so power production is safe”.
Now I will digress for just a bit towards a neuroscience principle which is called “Hebb’s postulate”. Hebb’s postulate says, in terms of neuroscience, that “cells that fire together wire together”. What this means is that neural connections that fire together often tend to get better over time and this, in turn, will increase your power output. It’s basically the whole principle of “coordination” if you will. Repeating something over and over and over will strengthen that firing pattern and will improve coordination, both intra and inter-muscular coordination.
In our case, the muscular irradiation will improve inter-muscular coordination. If you take your time to use this principle of muscular irradiation and do it (squeezing your glutes, abs and forearms) every time you strength train or do power movements, this will, over time, get better and better. You will tend to do it automatically every time you do strength and power movements.
What does that translate into? It translates into greater strength, greater power and lower injury risk. It really, really pays off and it really makes your body work as a single unit. This actually is the concept on which “functional training” is based off. It is, to some extent, the whole concept of compound movements instead of isolation exercises in the gym – to make the body work as a single, unified force. It’s just that muscular irradiation is the next step into making this work at the BEST possible level.
What is really interesting is that a lot of people will naturally tend to use muscular irradiation more or less automatically. If I ask you to lift a heavy weight off the floor, chances are good that you will take a big breath and then really contract your abs, clinch your teeth (by the way – this is another area of irradiation – squeezing the jaw muscles tends to provide additional boost in strength) and then pull the weight. Possibly the least used group of muscles people naturally tend to use is the glutes, but that’s because in many people the glutes have been shut down for reasons that we already discussed (like tight hip flexors, prolonged sitting, hamstring or quad dominance etc). That’s why you also make these weird faces when you lift stuff or do strenuous effort – you close the epiglottis, generate intra-abdominal pressure and generate jaw tension, which in return makes your face look weird.
So the next time you hit the gym, or do your favorite power movements, try remembering that muscular irradiation exists and try to always take advantage of it. Not only you will see an instantaneous increase in strength and power if you weren’t already using it naturally, but you will also increase the safety of your exercises and, over time, based on Hebb’s postulate, you will make your body use it automatically making the power and strength gains permanent.