What You Need to Know: Stretching
Level 1: Amateur
Welcome Players! If you want to Train Like a Pro, you need to learn how to Stretch Like a Pro. I’m going to detail everything to consider when figuring out the most effective ways to stretch for you. When should you stretch? What muscles? Does stretching even do anything? How do I stretch? Does yoga count as stretching? You’ve got questions, I’ve got answers. We’re going to peel back the layers of misinformation and clarify what exactly it is stretching does that’s so beneficial (yes, it is beneficial) and how you can best take advantage of the proper way to stretch in order to maintain your physical readiness. We’ll start by stretching out our lungs, deep breath… OK let’s go!
Anatomy of a muscle
Static, dynamic, ballistic, or other
Length vs Tension (short/tight, long/tight)
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The Warm Up!
Definitions you need to know:
Range of motion - the motion of a joint, is determined by the length and tension of the muscles that surround it. Ex: the ROM of the wrist is determined by the balance between the wrist flexors & extensors.
Mobility - describes the range of motion (ROM) of a joint, as determined by the muscles that surround it, during controlled active movement without assistance. Ex: How far you kick your leg in the air = hamstring mobility.
Flexibility - describes the ROM of a joint as restricted by the muscles that act on it in a passive or assisted setting. Ex: How far you can bend down and touch your toes, using gravity or pulling on the back of your legs = hamstring flexibility.
Proprioceptor - a certain type of cell in your body that senses changes in position or movement and relays that information to the nervous system.
Sensory perception - the information sent to the brain by receptors throughout the body as it relates to our senses. This information is then processed by the brain and influences a motor response. Ex: Stepping on a nail elicits sensory receptors to send pain signals to the brain, which then responds with a reflex to pick your foot off the nail.
What does it mean to “Stretch”?
We know what it means to stretch a rubber band. It means to elongate, and because of the rubber bands elasticity it allows for the rubber band to lengthen and then retract without deformation. This is a good visual for very basic understanding of stretching, but you’re not here for the elementary version; you’re here to Stretch Like a Pro! So we’ll have to learn a little muscle physiology to understand the concepts on a deeper level.
Below we have a very basic anatomy of a skeletal muscle. The muscle tissue itself is made up of multiple tiers of packaged muscle fibers, kind of like Matryoshka dolls. The smallest structural unit of a muscle is the myofibril, which is bundled together, and then that bundle is bundled together again into a muscle fiber, which are then bundled again in a fascicle, and then finally groups of these fascicles are put in one final bundle to create the skeletal muscle as we know it.
Skeletal muscle has contractile properties, which means that these layered-bundles of myofibrils can be stimulated via the nervous system (brain, electricity) to shorten, and with absence of stimulation will relax (lengthen). The specifics of this you can read more about here.
The only tissue in the human body that is capable of creating contractions is skeletal muscle, cardiac muscle (heart), smooth muscle (intestines), and new research is beginning to show the contractile and transfer-of-force properties capable from fascia. Notice the two things not capable of contraction are tendons and ligaments; they are connective tissue.
With a little better idea of the structure of a muscle, let’s introduce two cells that help our brain protect our skeletal system. These are muscle spindles and golgi tendon organs. [I was going to make a joke about how there must have been a guy named Golgi who discovered this structure, but turns out that’s actually true)
The role of both of these cells is to send information to the brain about the current state of our skeletal muscle. What differs is the conditions that they send information about.
Muscle spindle’s relay feedback about the length of the muscle, while golgi tendon organs relay feedback about the rate of force development (or tension) of the muscle.
The above is a critical concept that determines the selection of which type of stretching you should do depending on the outcome you’re looking for.
Muscle spindle - responds to changes in length
GTO - responds to changes in tension
These two proprioceptive receptors are vital to protecting the structural integrity of our body. The information they send to the brain about the state of the muscle gives our nervous system information it needs to protect our skeletal muscle from operating outside of its capacity and to initiate reflexes to prevent injury.
If a muscle is lengthened too quickly (think running and you slip), the brain receives a signal from the GTO that there is a rapid increase in tension of the hamstring (the muscle that would lengthen as your leg is flying up in front of you); the brain receives this signal (technically this signal only makes it to the spinal cord before a motor output is sent back, but the complexities of the nervous system won’t be discussed here) and reacts by stiffening the hamstring muscle to prevent overstretching of the muscle and possible damage to the joint. Because of this stiffening the force of the slip causes us to lose balance instead of tear our hamstring, and down we go. Painful? Sure. But no structural damage. Mission accomplished by the GTO.
The muscle spindle on the other hand is much more nuanced. It responds to physical changes in length of the muscle fibers themselves, giving our brain valuable proprioceptive information that determines out ability to create movement. It acts as a limiter for the amount of flexibility your body can produce, keeping us safe from operating in ranges of motion that we are not adapted too. When you bend down and (try) to touch your toes, its the muscle spindle in the hamstrings that tells the brain how far down you can get before it becomes unsafe. If you rarely try to touch your toes, your ability to reach further will be limited by the feedback sent to the brain from the muscle spindle in your hamstring. If you’ve done this a thousand times, the muscle spindle relays the amount of stretch the hamstring can provide at a much later stretch point.
Coaches note: This is a very basic anatomical summary of how our body perceives a stretch of a muscle. There is much more involved in the process from a variety of factors, but that depth is outside the scope of todays article.
Types of Stretching
It seems like there is an ever-growing list of forms of stretching as people look to create ‘new’ (recycled) techniques, brand them, throw a copy write on it, and sell it to the masses. I’m looking at you stretch zone (avoid at all costs).
So I’ll break it down into the main traditional forms of stretching that have been well studied in science and then talk about more refined neurological techniques that are very effective as well.
Static stretching is simply the act of lengthening a muscle and holding for a prolonged period of time. Within static stretching there are two types you can perform, active or passive.
Passive stretching means you are not contracting a muscle, like the name delineates, you are passively allowing the muscle to lengthen.
Active stretching is when you provide effort to contract muscles so that you are physically creating the stretch with your own tension.
Static stretching has the largest impact on the sensory feedback of the muscle spindles (hope you didn’t forget them already!). Because the muscle spindles act as a mobility limiter, it is imperative to be able to access and control a ROM before you attempt to perform within it.
If your goal is to increase the height of your Tae Kwon Do axe kick, and you have not exposed your hamstring and groin muscles to the expected ROM passively, it will be difficult and probabilistically unsafe to attempt to achieve those ranges in a high-velocity manner.
Static stretching works mechanically on adjusting the sensitivity of the muscle spindles. The more you stretch a certain muscle, the less sensitive it becomes to the stretch response in that range. And because the muscle spindle relays proprioceptive information, static stretching can be a powerful tool for exploring movement capabilities and restoring proper movement patterns that have become inhibited to due shortened muscles.
Dynamic stretching utilizes active movement to propel the body into an extended range of motion, but does not include a hold at the end of that range. It’s also important to note that extended ROM does not mean maximum ROM. You’re simply getting your body past it’s normal ROM in an active manner and then returning. A dynamic hamstring stretch is demonstrated below.
Dynamic stretching will have a small influence on the muscle spindle (much less than static) and will have a moderate effect on the GTO (depending on how far you take the stretch). It provides a powerful balance of improving both active and passive range of motion with moderate effort.
It’s important to note here that dynamic stretching is NOT the same as a dynamic warm-up; hence the different names. There are 3 goals of stretching, to increase:
expressed muscle length
If the dynamic stretch isn’t putting the body in a position to influence the muscle spindle or GTO, it’s just a movement, not a stretch.
The most misunderstood and often-misused form of stretching is ballistic stretching, which uses a combination of momentum, body weight, and gravity to ‘bounce’ into and out of an extended range of motion in short, oscillating movements.
We can see this is the same position as the dynamic hamstring stretch example used before except in order to perform it ballistically he stays towards the end ROM and bounces in & out of a max stretch.
There is a greater influence on both muscle spindle and GTO sensory perception from ballistic stretching since the position is held at the end ROM and is dynamically pushed into further ranges via the ballistic action.
Ballistic stretching is one of the most advanced forms, and is not recommended or necessary for most people. With that being said, those with a high training age and understanding of the limits of their body can utilize ballistic movements in an extremely effective way.
If you do perform ballistic stretching, it should not be done without prior warm-up and you should be careful not to over-perform the movements. Sensory desensitization WILL occur to where your nervous system grants you access to further ranges of motion, but if you are not prepared to own those increased ranges it will hinder your improvements and potentially set the stage for injury.
If we zoom out to the big picture, our skeletal system (bones + muscles + tendons + ligaments) is the hardware. Our nervous system (brain) is the software.
Our skeletal system can only do what our nervous system tells it to. Even reflexes are programmed in the nervous system at the level of the spinal cord.
As science’s collective understanding of the nervous system grows, we have found increasingly creative ways to adjust the sensory perception received by the brain in order to modulate the motor output instructions sent to the muscles. There are ways to change the nervous system so that we can better control, and improve mobility of, our muscles.
The following techniques are based in principles of neurological-sciences and biology, but the complexities of which I will not be covering here.
Proprioceptive neuromuscular facilitation (PNF) was a technique developed in the 1940’s as a way to physically rehabilitate those suffering from neurological conditions such as stroke, multiple-sclerosis, etc. It is based off of neurological patterns that are pre-programmed into the human nervous system, called motor-programs, of which their foundations set the stage for all our complex & intricate movements.
The Philosophy and Basic Principles of PNF, together with the specific spiral and diagonal patterns, make up the cornerstone of PNF. PNF also includes motor learning and functional retention of newly learned activities with the repetition of a specific demand; the use of the developmental progression of motor behavior that enables patients to create and re-create strategies of efficient functional movement; and the biomechanical and behavioral analysis of motor control. 1
While the technique of PNF for neuromuscular rehabilitation is rather sophisticated, its principles can be extracted as a way to influence our nervous system and achieve increases in range of motion, almost instantly.
The 3 main types of PNF stretching techniques are:
There are videos linked to each, but I will briefly explain them as well. They all involve taking the muscle to the point of its stretch, contracting the muscle being stretched without moving the body-part (hold-relax), contracting the muscle being stretched while allowing it to reduce it’s range of motion (contract-relax), and then contracting the opposite muscle being stretch to increase the stretch (hold-contract-relax).
You can do these without assistance by getting creative in your positioning or utilizing bands/straps depending on the muscle you’re trying to stretch. While PNF is highly-effective, it can not replace other forms of stretching for sustainable increases in ROM and mobility.
PNF works because of the influence of the nervous system, but as we’ve learned there are more influences to mobility that need to be addressed (muscle physiology - muscle spindles / GTO’s).
Another proven technique to increase ROM is nerve flossing (glides/flossing is interchangeable). This operates under the same principle that the software (brain) controls the hardware (muscles), but under a different set of circumstances.
Some quick background: the nerves that innervate your muscles are wrapped in sheaths. This is not only to protect the nerve, but also to allow for increased transmission of signals. For various reasons, the connective tissue between the layers of muscle that house these sheaths can become ‘sticky’. When the nerve either doesn’t glide well within its sheath, or if the sheath itself doesn’t glide against the layers of tissue, your nervous system will instinctively restrict access to ranges of motion that could put the ‘sticky’ nerve in a precarious position. Your body will always protect itself!
So regardless of how desensitized your muscle spindles and GTO’s are, or how much you’ve been through PNF techniques, without freeing the nerve you will experience restricted ROM. Thankfully nerve glides as a mobility technique are easily done! They are specific to the nerve you are trying to mobilize. Their effectiveness is purely based on whether or not you have a nerve restriction; if you perform a nerve glide and nothing happens, you didn’t have a ‘sticky’ nerve problem. If you perform a nerve glide and your ROM improves, well then you most likely did!
A simple explanation of a nerve glide is you position your body so that the beginning and end of the path of the nerve is at maximum length, and then oscillate movements at both ends (in the same direction!) in order to mobilize the nerve without stretching or damaging it. A nerve glide directed at the lumbar spine region, sciatic nerve, and hamstring is below:
There are multiple ways you can perform a nerve glide for the same body part, the selection of which comes down to your specific scenario.
Now that we know what stretching is, the different types, how they’re performed, and the different effects they have on muscle physiology, let’s clear up the false information you’ve probably been fed on pro’s/con’s of stretching.
“Never Static Stretch Before a Workout”
Where it comes from: There is bountiful research that demonstrates that static stretching performed immediately before exercise inhibits maximum voluntary contraction (strength) and rate of force development (power). That part is true.
What they didn’t tell you: The keyword that was cherry picked in the research was immediately. These studies performed 90s+ of static stretching and then in <2 min performed maximum strength/power exercises. From what we know about muscle physiology, this makes a lot of sense. If the muscle spindle, GTO, or nervous system has just been influenced to allow greater ROM, then immediately expecting it to stabilize for maximum force transmission inherently would be difficult. The shorter the stretch duration and the longer the time was between the stretch & performance test, the less it was affected.
The truth: If you keep your static stretching to moderate hold times (~60s), along with perform a proper warm-up after stretching and before performing exercise, you’ll experience no negative effects on performance. The only caveat is when performing maximum-intensity exercises (think your 1 rep max, or 40-yard dash at the NFL combine), then to err on the safe side you should abstain from static stretching within 1-2 hours before competing in a maximum-performance event.
Stretching Decreases/Increases Your Risk of Injury
Where it comes from: Studies with large participant groups look at stretching before, during, and after exercise and compare to those who don’t at all. When the cohort of the population studied shows beneficial effects, stretching before a workout reduces your risk of injury! Hooray! And when the cohort studied shows negative effects, stretching can be shown to actual increase risk of injury! Aw. What gives?
What they didn’t tell you: These studies took huge groups of people, which in research design ends up being mostly college-aged students at the school funding the research, and then put them through a pre-determined protocol. Some people get injured, some don’t. This is because trying to figure out the effects of generic stretching on a highly individualized process without accounting for the incredible unique differences in physical capabilities between subjects, well, is prone to provide inconsistent results. Oh, and they also found that the higher the training age of the subject, the greater buffering effect they have against any ‘negative’ effects of stretching. Surprised that those that have more experience stretching & exercising tend to have less negative effects from stretching & exercising? I’m not.
The truth: Whether or not stretching is right for you is completely dependent on, YOU! If you are a female (physiologically hyper-mobile vs. male), yoga-practicing, low-intensity exercising person, then chances are your need to stretch is very little. On the flip side, if you are an older, male, body-building style exerciser, than chances are stretching is going to provide significant positive effects. Don’t take general recommendations for a specific inquiry. Train Like a Pro means you should be evaluating all your individual needs and pursuing the appropriate solution that brings you closer to your goal.
(INSERT STRETCH HERE) is Bad For You
Where it comes from: People that want to impose their bias onto you. You know the type, you’ll be doing a stretch in the gym, and they’ll come up to you, “Hey, you know that stretch isn’t good for you. You should do this instead”. Just smile and say OK. I get this all the time. If only they knew…
The truth: No stretch is inherently good or bad. Like the previous myth, this is fully dependent on you and your specific body. There are very few stretches that when performed correctly are inherently bad. And vice-versa, every stretch can be bad for you when performed incorrectly. HOW you perform the stretch is just as important as WHY you’re performing the stretch.
Length vs. Tension
You can certainly follow a cookie-cutter stretch routine that promises increases in mobility of muscles X, Y, and Z, but you’re also potentially wasting tons of times stretching muscles that don’t need it.
How do you know which muscles need it? We’ll go back to our most basic proprioceptors again, the GTO / muscle spindle. Notice that I’ve explained that when you stretch you feel the perceived stretch, which implies that you’re not actually changing the legitimate length of the muscle fibers themselves. This is true. As a fully grown adult, your muscle fibers will not change in physical length. But they will change in expressed length. Here’s the difference.
Many people will stretch a muscle because it feels tight. This is a perception. Your various proprioceptors relay signals to your nervous system that tension in the muscle is high, and your conscious self interprets this feeling as “tightness”. What you feel is the perception and interpretation of tension. (a little inception-esque here, I know)
When you use a goniometer to measure the ROM of a joint, indicative of the resting length of the muscle that acts on it, you’re getting a measurable number that tells you the practical length that muscle is expressing. If you can’t bring your leg up to 90° while lying on your back, your hamstring is “tight”. But that’s the same word that we used to delineate tension… what gives?
If we dig a little deeper, we realize that we can have two different types of tightness. Aptly described, short+tight or long+tight. With nomenclature like this, we’re distinguishing between the resting length of the muscle as determined by muscle physiology and nervous system as well as the tension perceived by the brain.
In order to determine if a muscle is short/long, we simply use ROM measuring techniques to identify the practical resting length of the muscle. If you can get your leg to 90°, you have adequate range of motion and flexibility in the hamstring, and it would be neither. If you can only get your leg up to 45°, we’d say that your hamstring is short (we’ve yet to determine tension). If you can bring your leg to 150°, we’d say your hamstring is long.
Typically, short muscles will restrict ROM and cause your movements to work in a compensatory pattern. Long muscles can cause instability in joints and be prone to overuse or hyper mobile injuries, but this is not always the case. Someone with a long muscle but high levels of control will not run into these issues.
Due to the length-tension relationship of muscles, which says that muscles have the greatest ability to contract towards the middle 50% of its resting length, we know that if a muscle is either shortened or lengthened too much it will inhibit its ability to contract.
Using this knowledge we can pretty assuredly assume that if a muscle is lengthened too much, it will feel taught, but because of its inhibition on the length-tension curve will be weak. Determining if a muscle that is shortened is also weak on the length-tension curve is a much more difficult task left to clinical neurological-based practitioners.
Building Your Stretch Routine
Now that we have all this information to use, which stretches should you do?
That depends! What’s your goal?
If you’re reading this and exercise infrequently, stretch almost never, and live a rather sedentary life (I hope this is none of you) then literally any form of stretching will begin to benefit you.
But if you’re training for a specific adaptation, then we need to evaluate a few things.
Do you have any skeletal alignment dysfunctions that prevent optimal length-tension relationship of muscles?
Do you have any mobility restrictions that prevent you from performing your required task or movement?
Do you activate a muscle repetitively in a shortened range of motion during training?
Does your repetitive training or task include unilateral or asymmetrical motions that are not balanced out within the practice?
Could improving ROM, mobility, or flexibility contribute to increases in performance?
If you answered YES to any of the questions above, then you can and should be stretching regularly.
Which type of stretching should you do?
For most problems related to a short+tight muscle, you should be using a combination of static and dynamic stretches, along with PNF sprinkled in before your training if the mobility improvements will lead to a more productive session.
If your problems are related to balancing of repetitive motions or shortened ROM, then while PNF stretching is effective, again static/dynamic stretching will give you more sustainable results.
Some Examples to Get You Started
A bodybuilder lifts for 2 hours 6x/week. They have adequate lower body ROM due to them performing full ROM exercises frequently (squat, deadlift, RDL). Their upper body ROM, especially their shoulders, is severely lacking. Their upper body exercises are done mostly on machines in very short ROM. So while they solve for building muscle, if they don’t want to end up like this guy -
- they should be doing occasional to frequent stretching AFTER their lifts to balance muscle tension and ROM without affecting their strength gains. This will also reduce the likelihood of compensations or injuries due to dysfunction.
A collegiate Track & Field athlete competes in the 400m dash. They train vigorously every day mostly performing sport-specific work, but 3x/week utilize resistance training to improve strength and power output. Following their heavy strength training sessions, their hamstrings and glutes stiffen (result of soreness) and inhibit the quality of their next running session. To avoid this short-term decrease in performance due to resistance training, they can static and/or dynamically stretch after their resistance training session and utilize PNF stretching before their track sessions to ensure full ROM before sprinting.
You’ll need to evaluate your own training plan, goals, needs, limitations, and other variables related to your performance in order to determine what and how you should be stretching. Have a specific question related to you? Drop it in the comments and we can use you as a case study!
Train Like a Pro is not meant to give you all the answers. It’s meant to give you access to information so that you can critically think and solve for what solution is best for your specific environment. If you passively read the information provided and don’t seek to apply it to your situation, you won’t be any better off because of it. Being unsure and seeking help is OK, that’s what our growing community and I is here for! But it’s not OK to passively expect someone to provide you with a step-by-step plan to achieve your goals. Take responsibility, take action, and Train Like a Pro!
Disclaimer: This is not medical advice. The content is purely educational in nature and should be filtered through ones own lens of common sense and applicability.