To Stretch, Or Not to Stretch...

Stretching modalities can be traced back for centuries and is one of few modalities that has effectively stood the test of time. There are a number of specific types of stretching applications that have been developed over the years. Among the more commonly practiced variations in the sport performance setting, we have dynamic & static variations, active and passive modes, proprioceptive neuromuscular facilitative (PNF) stretching, and ballistic/cyclical types of stretching. Broadly speaking, each of these can be valuable for athletic performance and/or general fitness & health. But as we will investigate in this article, the primary point of interest should not be whether or not “stretching is beneficial”, but rather, how and when do we make it beneficial for the athlete(s) we’re working with?

Few topics have been as heavily debated within the human performance model as stretching. As with most things, we tend to give our attention to the two ends of the spectrum, presenting only extreme myopic viewpoints in “red pill or blue pill” form, forcing us to decide between the two. The reality is, there are several influencing factors and variables that need to be considered with stretching protocols. Despite what you may have learned or seen, there are good and bad stretching applications. There is a proper and improper time to perform stretching variations, and likewise, there are optimal and suboptimal durations, frequencies, and ratios for how much stretch work an athlete should perform.


What Does the Research Say…?

The research archive for stretching is robust, dating back nearly a century. Quite frankly, you can cherry pick to frame just about any stance on stretching for sport performance that fits your narrative. But if we examine the chart below, which summarizes meta-analysis findings, we can surmise a few things. First and foremost is that stretching appears to do what it’s supposed to do- acutely improve athlete’s flexibility (technically, tolerance to stretch), improve joint mobility, and may reduce the sensations of tightness/exhaustion (4).

Additionally, and, somewhat surprisingly, response doesn’t appear to differ much across different stretching types. Most improvements are modest, and transient irrespective of stretch type, and the most significant variable is consistency over time to drive long-term adaptations. Stretching will not prevent injury, and rarely (directly) improve performance, but at a minimum, stretching, mobilizing, and soft tissue work are a necessary component to developing well rounded athletes.


What Does Rude Rock Say…?

The consensus that I’ve found is that stretching is largely a neurological endeavor. This is a perspective I’ve adopted from Stu McGill, who once said “stretching is nothing more than playing with the neurology.” While at first I didn’t fully understand what he meant by this, over the years this premise has started to come into focus. While stretching is obviously implicating the muscles, connective tissue (fascia), and joint capsules, all of these structures are governed by the central nervous system (CNS) & peripheral nervous system (PNS). Thus, the mechanical components should only become the focal point once we’ve established the nervous system is in good order. Moreover, when I say CNS is the governing factor, we can also include the proprioceptive bodies in this statement.


As we know, proprioceptive bodies are found everywhere throughout the body (in the hundreds of thousands, if not more). Predominantly, proprioceptors can be found in fascial tissue (Paccini & Ruffini fibers, interoceptors, etc.), joint capsules and ligaments (mechanoreceptors), and in tendon and muscle (golgi tendon organs and muscle spindle fibers). Collectively, these proprioceptors serve as the frontline of our sensorimotor network, which are constantly receiving and processing external stimuli and internal state to organize and prepare the body for imposed demands (2). And when these proprioceptive bodies are impaired or inoculated, it can create a sensation of tightness or restriction despite there being no “real” mechanical limitation.


This is all a roundabout way of saying- stretching, mobility, and soft tissue work are a bit more involved than being default options to throw at athletes when you have 10 minutes to spare at the end of a session. Connective tissue management and priming muscle function go beyond throwing a resistance band at someone and telling them to loosen their hammies up real quick before hitting the squat rack. But to set the theme for the remainder of this article, here’s a short summary for how I view stretching:

  • Stretching is mostly a neurological endeavor, with several other systems contributing to the presence or sensations of tightness, movement restriction, and limitations.

  • Effects of stretching are largely transient, and to make long-term changes requires long-term consistency.

  • Stretching should not be the primary thing for any athlete but should be a part of the program for almost every athlete.

  • When desired results aren’t obtained, something needs to change (i.e., stretching religiously with no resolve).

  • If the input doesn’t change, don’t expect the outcome to change.

  • The effectiveness of stretching applications, and the emphasis of the applied stretch is determined by the parameters in which it’s applied, not necessarily the exercise/ movement selections themselves.

  • Choose your battles wisely. If athletes get a psychological benefit from some additional stretching/foam rolling, don’t be averse to it. In reality, it’s likely doing no benefit but also no harm.

General Factors for Stretching

With an abundance of key influencing factors, coaches should be mindful and open to multiple training applications, treatment options, and in some cases, outside professionals to provide the optimal solutions. But first, we need to separate the variables we do and don’t have influence over. There are several structural factors that no matter what are out of our control (i.e., skeletal abnormalities, tendon insertion, muscular fiber type).


Equally, compounding stressors are virtually out of anyone’s control (i.e., practice volume, academic stress, personal stressors) and must be evaluated for the sake of restorative applications. Additionally, we look to individual factors such as an athlete’s biometrics (i.e., age, recovery state, sleep). The context of the situation should inherently be at the precipice of decision making, and in doing so the majority of our exercise selection/protocols can be determined for us. A final consideration is the coach’s ability to instruct/implement certain modalities. Every facility/coach has their expertise, and for strength coaches planning recovery work, it’s imperative to not only stay within scope of practice, but also within their competency/ability.

Passive vs. Active Ranges of Motion


A foundational evaluation for me is looking at passive range of motion (PROM) and active range of motion (AROM) comparatively. As outlined in the graphic below, PROM is achieving a particular ROM with external assistance (i.e., manual, loaded, unloaded) and represents the tissues extensibility (ability to lengthen) and the joints ability to articulate. Generally speaking, PROM is mostly indicative of connective tissue function, as the fascial tissue is the first limiting factor in passive stretching (3). As for AROM, this is where the individual achieves a particular ROM unassisted (gravity aside) and is more indicative of musculotendinous and neuromuscular function. AROM is a little tricky, because we can have AROM where the individual is unassisted, but passive in their stretch efforts and then as unassisted but with muscular contraction. Broadly, having the individual contract the antagonist muscle group during the stretch emphasizes more of the tendon structures, whereas no contraction is going to be more of a muscular emphasis (3).

The reason PROM/AROM evaluation is so important to me is because- in my opinion, this represents the “window of vulnerability” in which injury can occur. Having significantly greater PROM (ability to lengthen to end range) than AROM (ability to stabilize at end range) is essentially having access to ranges of motion that cannot be controlled, and for this reason, may propagate injury risk. Think of it like this, if I have an athlete who has 20° of passive hip IR and 5° of AROM, they are much more of a liability than the athlete who may only have 10° of passive hip IR, but 8° of AROM. Even though the second athlete may have a limited ROM based on standard norms, they can control 80% of that “limited” range. Whereas the first athlete may be able to move into “normative” ranges passively, they are only able to control 25% of that ROM, which again at least in my mind, is a dangerous place to be.


This is also a great demonstration as to why it’s critical we don’t over-mobilize our athletes. We not only need to be thorough and objective in our assessment, but also understand that stiffness and “tightness” are often advantageous for athletes. And moreover, if we are dosing athletes with copious amounts of mobility/flexibility work, it needs to be backed by comparable strength work that gives function to the newfound ranges of motion.


Stretching Parameters

Far more important than the movement or modality selection itself is the parameters in which we apply stretching applications. There are innumerable ways to dress up stretching and mobility applications, and while we’re all familiar with a handful of common distinctions (i.e., PNF stretching, or band traction), there are several more that often get overlooked. The chart below provides a more complete list, but a few that I’ve particularly found success with are coordinating breathing patterns and varying between stretches with and without muscular contraction. Adding a specific breathing cadence to stretching and mobility work is low hanging fruit, that I believe does two things in particular. First, it gives the athlete more specific instruction for movements that have a tendency to be viewed as passive or “boring”- this is simply a way of making the movement matter more to them. Beyond that, we are also helping promote more parasympathetic drive by emphasizing exhalation, which allows the athlete too create greater stretch excursions and perhaps improved stretch tolerance (1).

Now speaking to the contraction piece, this is a way we can emphasize or de-emphasize specific structures during our stretch. For instance, if I’m having someone do a RFE flexor/quad stretch, I can set this up differently to prioritize specific demands. I will often use a band set up for the back leg support, and the reason being is this gives the athlete the opportunity to either passively support their back leg during stretch excursion- which would be more of a muscular-fascial focus, or, I can have them contract their back leg down into the band shifting the emphasis more to the musculotendinous junction. Reason being, when we add muscular contraction to a stretch, the contraction pulls on the tendon shifting the focus of the stretch. This is just one example but can be applied in a number of ways.


Loaded vs. Unloaded Stretching

The last point I wanted to cover with this is loaded and unloaded stretching variations. This is another element that needs to be evaluated by the coach, however, each application can be beneficial depending on the context. The primary point of emphasis with this is that stretching does not have to always be unloaded. In fact, there is some good evidence that suggests that passive/unloaded stretching is primarily emphasizing the fascial and connective tissue (3). Whereas using external load for the purpose of stretching & mobilizing makes the focus more musculotendinous.


This is again a way to stratify your approach to stretching. Is external load required for effective stretching, of course not, but it absolutely can be a pragmatic approach, especially for athletes who are more muscularly bound. A few of my go-to selections for loaded stretching include RDL/hinge patterns, pullover variations, and pec stretches.


Closing

Bringing this all together I’ll leave you with a few things. First and foremost, if you cross someone who has extremist views on stretching (albeit pro or anti-stretch), you’ve likely found someone who hasn’t examined much beyond their own musings. “The research” (as we all like to lead with…) is so abundant at this point that a case can be made in any direction. So, like with anything else, I would simply say be contextual and objective with your population. High school team settings obviously aren’t going to be doing much designated stretching, but it doesn’t mean it's neglected entirely. For private sector coaches working with older athletes, to include my current day-to-day, stretching and mobilizing will inevitably become more of your daily work.


As with the types, applications, and modalities I would again simply say try a bunch of variations early on, track the outcomes, and stick with what works best. There is no clear cut recipe, but there is an effective strategy for any athlete, it’s on us to put the two ends together. Last, for coaches who are profusely averse to stretching/foam rolling modalities or see them as trivial, don’t ignore the psychological effect this can have on athletes (especially older athletes). If someone lays on the ground or on a roller for 10 minutes before training, just let them be. Sure, it may not be optimal or doing anything profoundly beneficial, but it’s also likely doing no harm. Give them the time and let them check the mental preparatory box and live to train another day. No harm, no foul.


References

1.) Behm, D. Chaouachi, A., 2011. A review of the acute effects of static and dynamic stretching on performance. Eur J Appl Physiol. 111:2633-2651.

2.) Stecco, C. Functional atlas of the human fascial system. Elsevier Health Sciences.

3.) Stecco, C. Pirri, C. Fede, C. Yucesoy C., 2021. Fascia or muscle stretching? A narrative review. Appl Sci. 11,307.

4.) Wilke, J. Chapter 10- “What is it good for? An evidence-based review of stretching in sport and movement”. Fascia in Sport and Movement, Schleip, R. Handspring publishing, 2021, 117-127.



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