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Mobility Basics

Mobility vs stretching, and how/when to use them.

Here’s what you need to know…

  • Mobility and stretching can be an important part of training

  • Not everyone needs to stretch or mobilize, and not everyone needs both


Mobility. Stretching. Activating. Whatever you call it, it all refers to the same thing: getting ready to perform a movement to the best of your abilities, without working with stiff muscles or tight joints.

The handbrake

I use this analogy very often. Pretend you have a high performance car, let’s say a Ferrari. Everybody knows a Ferrari is a high performance car, and it goes pretty damn fast. Now let’s pretend you’re driving that super car. You theoretically have the potential to go at speeds upwards of 250 km/h. Now imagine you leave the handbrake on the car and drive off. What happens?

Well, a few things.

  1. You risk damaging the car;

  2. You risk an accident;

  3. You certainly won’t go that fast.

Now pretend you’re the super car. Tight muscles and joints are exactly like a handbrake. They make you risk injury by not being able to move in proper full range of motion (ROM) and will most certainly prevent you from going at your top speed.


For the purpose of this text, let’s define mobility work as what you would do with any kind of tool to increase the ROM of a joint without stretching muscles. This could be some massage, foam rolling, lacrosse ball work, etc.

Let’s say that stretching is the mechanical work during which you’d increase the length of a muscle past it’s normal resting position. This could be regular stretching, assisted stretching, or proprioceptive neuromuscular facilitation (PNF) stretching.

Finally, you need to understand that muscle activation is done solely by your nervous system and will not be done in any other way than your own will, unless we’re talking about electric stimulation, which is in the realm of therapeutic modalities used by physiotherapists and athletic therapists. It is a very famous buzz word on the interwebs, and should never be used in any serious setting, other than in the circumstances described previously. The correct term should be warming up, and it does come in preparation for any lift or movement. We will include it in the mobility or stretching section, depending on the criteria of lengthening of muscle fibers. Now, let’s forget about that terminological bullcrap and focus on what’s real. If you have “deactivated” muscles, you probably need a neuro-surgeon more than a squat rack.

We’ll see the basics of each and how/when to use (and not use) them in general.

Mobility work

Mobility being an increase in ROM without mechanical lengthening of the muscle fibers, it is a great tool to bring ROM to optimal status in preparation for any given lift. For example, if you’re doing squats today, you’ll want to improve ROM in the hip without weakening it. That comes with foam rolling the quads, using the lacrosse ball on the gluteals, tenderizing the TFL and IT band with a foam roller, etc. The last thing you want is to start stretching your hamstrings like a maniac, and then expect them to lift anything significant. You’ll end up with a proprioceptive discrepancy, not knowing exactly at what intensity you need to recruit your muscle fibers in order to lift the weight. This will in turn lower your self-efficacy, increasing risk of injury and effectively decreasing your strength. We don’t want any of that. You want your muscles to be recruited at the same rate and intensity every time you lift, so that you can understand the recruitment and use your muscles correctly while lifting.

In no situation would you want to increase ROM too far past what you need for the lift, as you will then end up not being optimal in your muscle patterns.


Stretching is the mechanical increase of the length of the muscle fibers. That should be kept for after workouts, when you’re nice and warm and don’t need your muscle fibers to lift heavy loads anymore. Again, in no way should normal safe ROM be ignored during your stretching.

How does stretching work?

Well, that’s a great question that’s a bit difficult to answer as it’s not entirely understood. But here’s what we know. Be careful, it gets pretty geeky.

First of all, let’s be clear: no permanent change in a muscle’s length is achieved with stretching. If you were to make your muscles permanently change in length with stretching, you’d be a lifeless mass on the floor, or you’d need serious reconstructive surgery. You’d end up with no joint stability and with much bigger problems than a tight hip or shoulder. Muscles are neurologically elastic fibers, and if you go to the point of permanently lengthening it, you’ll most likely rip it in two or make a tendon rip off of its attachment site. No es bueno.

So how does it work really? Well let’s see how a muscle fiber is made. You have the muscle belly and the tendon, the tendon being a tough piece of fibrous tissue that transfers tensile energy from the muscle to the bone it’s pulling on. Now without going into the deep anatomical science, let us introduce a small little sensory unit within the muscle belly: the muscle spindle.

That sensory organ is there to do one thing, and that is to detect changes in the length of the muscle it’s in. There are a bunch of muscle spindles in each muscle, and they all contribute to saving your life, or anything else you might do. Take those away, and chances are you’ll rip a muscle clean in half within a week. That sensor works by starting the stretch reflex. See, stretching is usually a bad thing, as it’s perceived by your body as danger and injury. Stretch a bit more, and you’ll feel discomfort. More, and you’ll feel pain. When you stretch, your muscle spindles feel what’s up. As soon as a certain threshold is reached, they initiate the stretch reflex, which is basically an autonomous (independent of the brain) contractile reaction. So the pain you feel is basically a muscle spasm coming from your muscle spindle initiating that reflex to protect the joint from destabilizing too much. It feels the stretch, sends a signal to the spinal cord to relay it to the motor nerve saying: contract! That will effectively make sure the joint stays protected.

To illustrate this, keep in mind that under complete anesthesia, everybody can do full splits, with no damage whatsoever.

So… stretching actually does what?

What you’re doing when you elongate your muscles is basically desensitizing those muscle spindles to the stretch itself. Let’s say you get a maximum stretch of an extra 10% on a muscle. What happens after that is that you get pain and it stops you from stretching it. Now by repeatedly (and with patience and caution) stretching that muscle, you’re basically teaching your muscle spindles that they do not need to fire so early, that it’s okay to go beyond that 10% stretch. It doesn’t mechanically change anything, it’s just building a neurological “callous” on them. Then after a while, you’ll get to 12% stretch before getting that pain reflex. Then 15%. Then more. Stop stretching, and they will slowly regain that sensitivity and reduce the ROM needed to get to the pain signal.

Ok, so I need to stretch to avoid injury, right?

Now, for those of you who think stretching reduces injury rate, I have bad news for you: it doesn’t. Sucks huh? Now if you have muscle imbalance and/or structural issues, by all means, do stretch if you need to fix that. But in general, stretching only makes you feel good. No reduced injury rates whatsoever. Further-more, it doesn’t stop or reduce muscle soreness either. Take a minute, I know you’re not feeling so good about this.

All in all, stretching may or may not feel good, and I’ll always recommend some stretches to make sure a person has normal ROM, but it’s certainly not something everyone absolutely needs to do.


So there you have it, the basics of the theory on stretching and mobility. As a general rule, you’ll increase mobility with non-stretching exercises before lifting anything, as you’ll want some of that tightness to assist in stabilizing the joints. And you’ll stretch afterwards if you have to correct something.

And keep in mind that if you have normal and functional ROM, if you want to do a squat and your squat ROM is great, well you might just not need any mobility or stretching. Simple as that. If you can move fluidly through the whole ROM of the exercise you plan on doing, then why try to fix something that works perfectly fine?

Now go lift, but stay tuned for a series of blog posts on how to prepare and mobilize/stretch for each category of movements. Get ready to learn. A lot.


Would you like me to help you with your fitness goals? Consider a live or online consultation! Kick start your progress with no-nonsense advice.

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Montreal, QC H3A 2K4


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