The Science of Mobility: Understanding the Body's Mechanics

From the outside perspective, mobility training is often perceived as a very basic approach; when something feels tight or sore…stretch it. While there is some merit to that (keeping things simple is incredibly important), the nuances to mobility training are quite complex. 

When I ask people what they think about mobility training, they all speak about the muscles. In most cases they refer specifically to stretching, but occasionally I’ll hear something along the lines of “muscle activation, control within our range of motion, and movement mechanics”, which definitely gets my inner mobility nerd's tail wagging.

See, while mobility training definitely comes down to the stimulus we’re placing on the muscle tissue, the real pursuit is in having an influence over the nervous system. When a muscle feels “tight” it does not mean it is inherently short. The muscle doesn’t literally lose length. It is still as long as it has always been, what’s happening is that the nervous system is just controlling the narrative through something called the “stretch reflex” (or myotatic reflex). The more we understand the stretch reflex, the better we can approach our mobility training with a high level of success. Let’s uncover the stretch reflex and have a look at how and why it has an influence on our joint mobility and biomechanics.

The Stretch Reflex

A Story About How I Felt Like A Smoker As A New Personal Trainer

It was the summer of 2015 and I had just started working as a personal trainer at a local “big-box” gym. Having just gained my CPT certification, I was convinced I was pretty close to knowing everything there was to know. Afterall, before starting work as a trainer I was rarely exposed to new concepts and ideas as I was surrounded by people who knew nothing about fitness. 

With the Dunning-Kruger effect in full swing, I walked around the gym with full confidence I could solve any problem that came my way. Need more strength? Easy, lift heavier weights. Want to lose fat? Cool, reduce your calories and be patient. Shoulders feeling tight? I got you, just stretch your lats.

After a few months of walking around with my head ballooned with uninformed optimism, I noticed that although my clients were getting stronger and beginning to truly enjoy exercise (solid wins), I wasn’t seeing good results in joint discomfort, fear of certain movements, and the muscle tightness they were experiencing. 

All while I was also fighting a personal battle of my own, dealing with shoulder pain anytime I would load the overhead position, sciatic pain when I would bend forward too far, hip impingements when I would squat past parallel, and just general low back pain. 

What a mess…

It was frustrating, but I continued on through the new found informed pessimism anyway….(this was my first time working in the fitness industry after being around the gym for a decade already, I’d like to say that I didn’t know any better, but my ego was likely the real obstacle that stopped me from asking for help)

Then, one of the veteran trainers at the gym had pulled me aside to have a chat. His name is Andre. 

Funny enough, although Andre had the most experience of any of our trainers at the gym, he was always the one asking the most questions, and this time he had a question for me. 

At that moment what Andre asked me didn’t feel like a huge impact, but it may have changed my life. He said “Matt, I’ve been seeing you on the gym floor and noticed you’ve been doing more and more stretching …have you ever heard of the stretch reflex?”.

While the name was definitely familiar from my CPT education, the information definitely never stuck; probably because I never had anything tangible to apply it to in order to help it resonate, until now.

Yet, like when a smoker takes that first puff of a cigarette, I swear I got an instant dopamine hit the moment I heard him say those words. 

In that moment Andre gave me a little glimpse into an entire universe that I was completely unaware of. He unintentionally pulled back the curtains and exposed the world of mobility training. I wasn’t hooked yet, but I definitely got a little smell of the worm. 

The science

It sounds like fancy jargon, but why does the stretch reflex even matter? When I say that mobility training is a game of influencing the nervous system, it is because the nervous system is what governs our range of motion. The stretch reflex is an autonomic (involuntary/unconscious) response that forces a reflexive contraction of our muscles to stop the lengthening process when they are being stretched. Just like everything else when it comes to our body’s, the “excitability” (how easily it is triggered) of the stretch reflex can and will vary from person to person, based on many factors. It’s as unique to you as your fingerprint. Said another way, when you stretch your muscles, your stretch reflex will inevitably be triggered, and stop you from achieving more range of motion.

While this might sound like a pain in the ass, its intended purpose is to protect you from injuring yourself by smashing your joints into their end-ranges. To stop you before you get pushed into a position that you have no hope of coming back from (imagine your legs quickly separating while skiing, forcing you into a deep split and you have no control over it).

Inside our muscles there are stretch receptors called spindles. These spindles will analyze the velocity and force of which our muscles are being lengthened. Once the muscle reaches a particular length, the muscle spindles will send a signal to the brain suggesting that we are reaching ranges of motion that we don’t have the capacity to manage yet. The brain will then send the signal back to the muscle to force an involuntary contraction while simultaneously relaxing the antagonist muscle (muscle that is directly responsible for the opposing biomechanical function - ie. in the case of knee flexion, the hamstrings are agonist and the quads are antagonist), which limits the ability to stretch the muscle any further. 

In order to begin to reduce the excitability of our stretch reflex, we must instill trust within our nervous system. We have to prove to our body that we can manage those deep stretched positions and show that we aren’t at a higher risk of injury within them. The way to do this is through fostering control and strength within the deep ranges. Once we have strength, we have proven the ability to manage force. Now our body believes that we can handle the deeper ranges of motion without losing control and smashing our end-ranges, so it grants us access to more range.

How The Stretch Reflex Impacts Movement Mechanics

Although we’re referring to the stretch reflex being active during the stretching process, a true takeaway here is that it is present any time a muscle is being lengthened to a particular range. Whenever we’re going through movements that apply deep ranges of motion, we will naturally be triggering our stretch reflex through the process. 

Considering that you likely train in the gym and inevitably expose yourself to deep ranges of motion (I friggen hope so), then whatever positions you are struggling to get into are likely a result of an excitable stretch reflex. Unless you are truly reaching your anatomical end range, you will be exposing your muscles to various lengths under load. This can trigger the nervous system to activate the stretch reflex as a security protocol in the event that you have not yet proven that you have control of the particular ranges you are exposing. While this may sound fancy and convoluted, at the end of the day this simply means that your movements in the gym can be stopped early in the process as a result. Your overhead position, squat, dips, deadlifts, front rack position, etc. may feel restricted and “tight” because the stretch reflex is excitable.

Expert Tips for Effective Mobility Training

Now, this is the part where we get into all the fun stuff that you probably came for. I would have started here, but I think having the information that we chatted about above can drastically change how you perceive movement and mobility training, so it makes for a good foundation.

In this section we’ll go over three mobility training tips that will have a large influence over your movement efficiency and pain reduction as well. Also, you know I can’t give you a blog without throwing some mobility drills your way, so we’ll make sure to toss some of those in there too. The three concepts are 

1. Active and engaged
2. Strength-based approach
3. Spend time in positions

Let’s break them down individually..

Active And Engaged

Mobility training is a game of influencing the nervous system. We need to find a way to establish trust with our nervous system by demonstrating that we have control within our movements. This is how we will eventually gain some control over the excitability of the stretch reflex and begin to calm the feelings of muscle “tightness” that many of us feel. 

It all starts by getting active. By learning to engage our muscles while they are close to their deepest ranges of motion. This will begin to send signals to the nervous system that we have the capacity to contract our muscles and thus have the ability to withstand force within those deep ranges of motion. The ability to withstand force is direct evidence that we can reduce risk of injury. This is the language of our nervous system.

If we can engage our muscles, there's proof that we can manage force. If we can manage force, we can reduce risk of injury. If we can reduce the likelihood of injury, we have proven to our nervous system that we are capable of handling our deepest ranges of motion and as a result, it will grant us access to more range of motion potential. And now we can restart the process. 

Stretching and gentle movement is fantastic for exposing our muscles to various lengths. This is an important part of the mobility training process. However, If we want to have a more rapid carry over from our mobility work into our fitness and daily life, we must get active in the process. 

Since stretching the hip flexors is one of the most common ways that people seem to approach their hip mobility, I’ll provide you with two active hip extension exercises that get the muscles engaging!

Eccentric Hip Flexor 

Front Split Liftoff

Strength-Based Approach

Considering how much we talk about it, it should come as no surprise that Primal Mobility follows a strength-based approach to mobility training. Although we do believe there is value in using passive techniques (exercises that don’t require muscle engagement), our ultimate goal is to foster strength within the deepest ranges of motion. Strength is the glue that holds it all together. This is where the long lasting gains are made, but also, this is where you truly start to feel the fruits from your labor. 

The reason that we chase strength so aggressively in our approach has everything to do with that stretch reflex thing we’ve been talking about. The more strength we have, the more force we can withstand, the more trust our nervous system has in our ability, and the less restriction it creates. 

The human body will naturally adapt to stress. How we apply this stress is considered a stimulus. So, naturally, the essence of getting stronger is to gradually and progressively apply a greater stimulus to adapt to. This is why we must find a way to implement progressive overload principles into our mobility training. With that said, since mobility training can be very challenging to add loading to (how do we add a barbell to a frog exercise?), we have to find ways to get more creative with this process…here are a few examples of progressive overload principles that we use within our protocols, that do not require loading:

• Reduced Rest Periods
• Increased Volume (sets, reps, workouts)
• Pauses
• Tempo
• Increase Applied Range Of Motion (use more range of motion in the particular exercise)

Spend Time In Positions

Again, our body is a master at adapting to stress. When it is challenged, it finds a way to overcome. Think about the position that you spend most of your time in throughout your waking hours. Although I would bet that you’re more active than the average individual (If you read this far, I know you’re a savage), it is still likely that you spend the majority of your time in the seated position. So, naturally, this is the position that your body will be most readily available to revert back to, because it is the most common stimulus that is being applied.

If we want our body to be available to certain positions, we need to expose our body to those positions more regularly, and they will become accessible. We can’t just spend 10+ years spending 8-12 hours per day sitting in a chair, and then assume that getting our arms overhead or that getting our hips into deep extension should be easy. We need to intentionally spend more time in the positions that we want access to.

Primal Principle #9 is to Spend More Time In The Positions You Wish To Improve. This is yet another reason why we apply progressive overload to our programming. We repeat the stimulus week after week to expose our body to varied ranges. It takes time, but it works!

Holistic Mobility: Beyond Exercises to Lifestyle Integration

Something I want to explore with you, is the concept of Holistic Mobility. This is something that we talk about A LOT with our members, and our students as it can have a massive influence on the long term functionality of your joints.

If we want to move better, lift better, feel more powerful, reduce our pain, and reduce risk of injury, it doesn’t only come down to training our mobility for 20-30 minutes per day. It’s also about how we move every other minute of our day.

Let’s talk about something that I call mobility habits. They are things that you can focus on in your day that will naturally have an influence on your long term movement potential, that don’t require you to set time aside to do another workout. It’s kinda like mobility - lifestyle integration. It sounds fancy, but all I mean by this is that we are going to find simple habits that have a positive long term influence on your mobility. 

Let’s dive in.

10,000-15,000 Steps

We all know that we should be aiming for more steps throughout our day. With the commonality of desk work these days, we’re all susceptible to greater risk of becoming sedentary. Aside from the obvious health benefits that come from maintaining a higher step count, we want to look at this from a mobility perspective.

As mentioned above, our body will adapt to the positions we spend the most time in. As we walk, we are offering movement to our entire body, but most importantly, our hips and spine. Every step we take we expose our hips to extension (opposite function that the hips are in when we are seated) and our spine will get some rotation as well.

10,000 steps has been the gold standard for step count for quite some time. This should absolutely be the number we strive for as our bare minimum for the day, but if I could give you a true number to aim for, it would be 15,000. This would roughly average out to be around 7 miles of steps per day. 

Don’t let this overwhelm you. The most important thing is progress…so if you’re well below 10,000, just start by setting a goal of a couple thousand more than you’re at, and build up from there over a few weeks. This is true holistic mobility. It will improve every aspect of your life, and your hips and spine will thank you for it!

Use More ROM In Your Training

Most people will generally just train through the ranges of motion they feel strongest within. Stopping their bench press just above the chest, their squats and dips just below parallel, and their pull ups with bent elbows. There’s absolutely nothing wrong with this either. There are a ton of benefits to training partial reps and training our body through our strongest ranges. But while our strength may increase with this approach, our range of motion dwindles as a result.

Sure, there are undeniable benefits to working through shorter ranges of motion on occasion, but don’t shy away from the fact that our joints and muscles will benefit in a massive way from being exposed to their full range under load. Take your bench press down to the chest, go through deep shoulder extension in your dips, get your ankles, knees, and hips working in max flexion in your deepest squat. These things aren’t mandatory, but they have an influence on how you feel long term.

Just remember that our deepest ranges are often our weakest, so you’ll naturally need to reduce the weight slightly as you begin to get into a deeper stretch in your daily training.

Get Out Of Your Chair More Often

If there's been one theme here, it’s to expose yourself to more ranges! If you spend the majority of your day sitting down, your ankles, knees, hips, spine, and shoulders will rarely be introduced to more range of motion than what you’re probably currently resting in while reading this (I’m sitting right now as I write this). 

Something that I have done for myself, and that many of our members have implemented, is regular intervals of standing/moving. We will set an alarm or just remember to get up periodically, and stretch our body out. This will not necessarily improve your mobility, but it will drastically reduce the onset of restriction - which is half the battle.

Set yourself up for success and get out of your chair every hour to move your hips, shoulders, and spine. A little “hack” that I’ve found to be super helpful, and kills multiple birds with one stone, is to stay very hydrated. It will force you to get up and out of your chair to pee far more frequently. Peeing every 15 minutes sucks, and can inevitably kill productivity, but it may be worth it in the long run depending on the goal! 

Taking Mobility Training Further

At the end of the day, the main thing to take away here is that our body craves movement, and it will adapt to the frequent stimulus at hand. In the event that we are feeding our body movement, the old adage “you are what you eat” rings true. Move often through deep ranges, and you will move well. 

At Primal Mobility we do what we can to simplify movement and mobility training so that it’s incredible easy to start making progress and remain consistent with your efforts. But it can still be confusing, overwhelming, and down right frustrating of a process. 

If you want to finally get it right, stop spinning your wheels and book a call with our head coach, Bekah. She’ll be able to explain to you what you need to do in order to reduce your pain and get back under the barbell with confidence in your body's ability.

Just click the button below and set up your free consultation with us!