A Modern Understanding of our Bodies Based on Science, Research, & Evidence! - Dr. Joseph D. Hoffman PT, DPT

A Modern Understanding of our Bodies Based on Science, Research, & Evidence! – Dr. Joseph D. Hoffman PT, DPT

Here’s a fun analogy: Would you use a hair-loss supplement if there was no evidence that it worked? Maybe, if you’re desperate. Now, what if there were other options which DID have promising evidence, not only short term, but also long term?

If you would favor the second option, then you should be doing the same with your health. There are many ways to treat an injury, prepare for exercise, and recover after exercise. Unfortunately, many are opinions or outdated evidence which has been since proven false (over and over and over).

The aim of this blog is to provide the most current, evidence-backed information to optimize outcomes and expedite your journey towards your goals. I have brought a few common misconceptions to the table to unpack and discuss the cold, hard truth that the evidence has provided us. This is not my opinion, this is my understanding based on the evidence which, as an evidence-based profession, is how it should be!

However, not all evidence is created equal and that is why this blog will be based on quality, overwhelming evidence to debug misconceptions. When I say evidence, I am referring to research studies, not “but, this worked for my aunt”, “but, this is what I was taught in school” or “it made my pain go away that one time”. Anecdotes are one of the lowest, least reliable forms of “evidence” and do not hold up when brought to scale and studied. Also, it takes an average of 17 years for our most current evidence to be translated into practice! Also, many interventions “work”, but not for the reasons we think are told they do (but, that’s a conversation for another day).

Much of the information in this blog will likely contradict what you have been told by magazines, the internet, or even other health professionals. It is likely contradictory to “common knowledge” and even some things that may have worked for you or someone you know in the past. However, this is what overall works best (MOST effectively, MOST often, and MOST optimal) and is MOST factual based on the literature. I ask you to keep an open mind and I have provided the references so that you can digest the evidence yourself and decide what to do with it.

I hope you use this information, patients and potential clinicians alike, to challenge your biases and improve treatment of yourself and others because if we don’t use evidence to influence our practice, we are no worse than those “health professionals” on Instagram or in MensHealth! Many of the ideas which will be challenged in this post are grounded in sensible logic and “make sense”, however, have been proven incorrect by the good ‘ole scientific method!

Healthcare is a business at the end of the day and, just like other businesses, there is always going to be someone trying to sell you something, whether it is a new tool, intervention, technique, or fear! Arm yourself with knowledge, sniff out the scams and pseudoscience, save yourself some money, and, ultimately, feel better! But, first…
The answer is 17 years, what is the question: understanding time lags in transitional research. Morris et. Al. J R Soc Med. 2011;104(12):510-520

But, first…

The answer is 17 years, what is the question: understanding time lags in transitional research. Morris et. Al. J R Soc Med. 2011;104(12):510-520

Let’s forget everything you know about stretching, bending, fascia, and your IT Band!

If you’ve ever had pain at the side of your hip or knee, you’ve probably been told you need to “roll out” your “tight” IT Band. However, that is akin to kicking at the ground and thinking the Earth will move. The most current, quality research suggests that the amount of force required (925kg) to deform the thick, fascial tissue of the ITB (just 1%!!!) is greater than what the human body can produce, even with tools. Therefore, foam rolling will be ineffective at “loosening” the ITB. Furthermore, you likely do not want a looser/longer ITB as studies show that LESS hip adduction (a motion limited by a “tight ITB”) was actually more beneficial! The ITB is a strong, tensile structure and it should remain that way! It has important tasks that require resilience to tensile stress such as helping us keep our knee locked out in standing and supporting our leg in single leg stance. We WANT stiffness there to take the brunt off our other muscles and ligaments. Instead, it would be more beneficial to strengthen the muscles that attach to lateral hip in order to decrease resultant over-tension/compression at the knee where the IT Band inserts.

But, what if foam rolling has helped relieve your pain in the past? Well….that’s fine! The good thing is, there’s no harm in it (other than bruising and temporary discomfort), however, there are much more effective, long lasting options available. Also, there are many reasons why you may feel looser or experience less pain, but it will likely be short term and it’s unlikely that the ITB has been actually lengthened, more so that relaxation of the surrounding musculature has occurred from noxious stimuli and/or your tolerance to the discomfort of stretching has improved. Which brings us back to another topic called “many times things work, but not for the reasons we think they work”. But, that’s a topic for another blog!

The IT Band is the longest and most massive tendon in the body and does not have the freedom of movement of other tendons! Again, it takes 2000 POUNDS of force to elongate the IT Band just 1%. No stretch or application of foam roller or similar interventions is going to be able to produce that much force!

*But what about the TFL, that attaches to the IT Band? It is possible to stretch this, but due to limited adduction ROM the hip naturally has, it is very difficult to apply enough tension to effectively elongate.
*But, but what about the glute max? Due to length, the hip is unable to flex enough to apply enough tension to glute max.

Too Long Didn’t Read: According to research, the length of your ITB is not likely to be the cause of your pain. You couldn’t lengthen it even if you wanted to. Less length may actually be more beneficial. Strengthen instead.
Three-dimensional mathemadical model for deformation of human fasciae in manual therapy. Hans Chaudhry et al. J Am Osteopath Assoc. 2008. Reduced hip adduction is associated with improved function after movement-pattern training in young people with chronic hip joint pain. Harris-Hayes et al. J Orthop Sports Phys Ther 2018;48(4):316-324

Despite the sage wisdom of Mama Boucher, it’s okay to round your back!

“Don’t bend forward like that, you’ll hurt your back!” We’ve all heard this. Its essentially common knowledge. But, where was this saying derived? Yes, it is the mechanism in which many people have injured their back, so that makes sense (even though it is likely the events/behaviors/lifestyle factors and decisions which led up to that incident, not the act of bending itself, which caused injury). However, let’s look at the evidence which may have initially influenced this idea as it has been perpetuated in healthcare for many years.

Many “myths” like these are grounded in what seems to be logic and anchored to some truths, however, are ultimately flawed and have not been supported by the literature. The general thought as to why bending forward is dangerous is because it places increased anterior shear forces on the intervertebral discs and this increases injury. Yes, increased shear can increase risk of injury, but, does bending forward exposure us to this danger? Does it expose us to increased shear? Some of the initial evidence which supported this idea is listed below. As you can see, the outcomes of the study did confirm that what was tested increased shear and infarct to the spine. However, the context is important!
Cadaver Study Damage accumulation location under cyclic loading in the lumbar disc shifts from inner annulus lamellae to peripheral annulus with increasing disc degeneration – ScienceDirect Tanaka et al (2001) Spine J, 1:47-56

This study used cadaver spines. Why is that an issue? Well cadavers have no active musculature or healthy ligaments to resist motion and support the spine as living humans do. Also, the parameters are an issue: this study repeatedly bent the spine to end-range thousands of times in a short period; something that no human spine would likely ever endure. Therefore, the results of this study cannot be applied to human models. Next!

Example 2: Live Mice Study: At least this study looked at a living organism. However, it used mice. We, fortunately, are not mice and do not behave like mice. Therefore, it would be a stretch to apply this to humans. Also, they compressed the tail of the mice repeatedly. Outside of unrecognizable vestigial structures, we don’t have tails to compress.
Lao YJ, Xu TT, Jin HT, et al. Accumulated Spinal Axial Biomechanical Loading Induces Degeneration in Intervertebral Disc of Mice Lumbar Spine. Orthop Surg. 2018;10(1):56-63. doi:10.1111/os.12365

Example 3: Dead Pig Study: Simple enough, we aren’t pigs. We are bipedal and our daily activities stress our spine much differently. Also, we are alive!
Anterior shear of spinal motion segments. Kinematics, kinetics, and resultant injuries observed in a porcine model – PubMed (nih.gov) Yinh & McGill (1999) Spine, 18:1882-9
Intervertebral disc herniation: studies on a porcine model exposed to highly repetitive flexion/extension motion with compressive force – PubMed (nih.gov) Callaghan & Mcgill (2001) Spine, 1:28-37 → 86400 cycles of flexion and extension with low loads at 35% ROM = disc herniated.

Why are these not relevant? Well, because dead, non-human tissues are not adaptable (able to positively change to better tolerate their exposure) and the tests performed are not reflective of how humans move/behave; unless you spend your nights performing 8600 sit ups consecutively! Our discs can adapt to tensile load to become more resilient and build an “armor”.

Now, let’s take a look at the current evidence using real life humans like you and me!

When lifting techniques were compared, bending or stooping vs. a squat lift (lifting with your legs a.k.a. the “right” way), the results showed very little difference and one study actually showed stooping to have LESS shearing on the intervertebral discs!
How to lift a box that is too large to fit between the knees – PubMed (nih.gov) Kingma et al (2010) Ergonomics, 10:1228-38
van Dieën JH, Hoozemans MJ, Toussaint HM. Stoop or squat: a review of biomechanical studies on lifting technique. Clin Biomech (Bristol, Avon). 1999 Dec;14(10):685-96. doi: 10.1016/s0268-0033(99)00031-5. PMID: 10545622.Straker 2002: A Review of research…
Straker LM. A review of research on techniques for lifting low-lying objects: 2. Evidence for a correct technique. Work. 2003;20(2):83-96. PMID: 12671202.

In summation, there is currently no evidence that lifting/bending with a forward bend is more dangerous than with a “neutral” spine positioning often recommended with squat lifting. Furthermore, there is virtually no evidence that bending your back is an independent risk factor for back pain. Also, there is no definitive evidence to conclusively show that bending your back actually exposes our discs to increased shear forces compared to a straight spine. Also, it is relatively impossible to keep a “straight” or “neutral” spine when lifting. There will always be some degree of lumbar flexion.
Christopher T.V. Swain, Fumin Pan, Patrick J. Owen, Hendrik Schmidt, Daniel L. Belavy, No consensus on causality of spine postures or physical exposure and low back pain: A systematic review of systematic reviews, Journal of Biomechanics,Volume 102,2020,109312,ISSN 0021-9290,

Too Long Didn’t Read: It is okay to bend your back! It is not necessarily better or safer to lift objects “with your legs”. The more you challenge your back, progressively, the more capable it will be and the more it will be able to tolerate.

“Is it better to stretch before or after my workout”. This is a common question in the clinic and it implies the assumption that stretching is a necessary activity. However, the evidence refutes this. Stretching has become a foundation of the fitness injury and it is often (over)prescribed in the clinic. But, why? Likely because stretching is easy, cost-effective, time efficient, and most importantly….it feels good! This is an instance when we conflate that if something feels good, it must be doing good and it must be doing what we intended it to do. For example, eating a Big Mac tastes good, but it’s not good for us. However, in this scenario, stretching is not necessarily bad for us, it’s more of a neutral effect and there are better options which accomplish the same task with added benefits. The only instance it is non-beneficial is if performed before sprinting or lifting and performance where muscle performance is hindered as a result. (include study).

You heard that correct, those old mantras of “you need to stretch first!” are grounded in tradition and perceived benefit, not fact. Otherwise, stretching is not harmful, there are just better ways to use your time.

Not to nitpick, but stretching also may not be working for the reasons you think (or have been told) it may be working. Research points towards static stretching improving your tolerance for higher levels of discomfort as being the reason for more mobility, not actual structural changes. Also, it takes A LOT of stretching to actually achieve a meaningful change in muscle fiber length. So if you want to lengthen your hamstrings by stretching alone, stretch a few times per day, every day, for weeks.
Konrad A, TILP M. Increased Range of motion after static stretching in muscle and tendon structures. Clin Biomech (Bristol, Avon). 2014:29(6):636-42

Again, not to bash our beloved stretching, but it does not remove lactic acid. But, what is the best option then? Active recovery. So, maybe 5 minutes on the bike instead of 5 minutes stretching.
CE E, Limonta E, et al. Stretching and deep superficial massage do not influence blood lactate levels after heavy-intensity cycle exercise. J Sports SCI. 2013;31(8):856-66

Also, stretching before a performance, especially anything ballistic such as running or jumping has been shown to actually decrease performance. You WANT that tension in your muscles!
Di Cagno, Alessandra1,2; Baldari, Carlo2; Battaglia, Claudia2; Gallotta, Maria Chiara2; Videira, Miguel3; Piazza, Marina4; Guidetti, Laura2 Preexercise Static Stretching Effect on Leaping Performance in Elite Rhythmic Gymnasts, Journal of Strength and Conditioning Research: August 2010 – Volume 24 – Issue 8 – p 1995-2000 doi: 10.1519/JSC.0b013e3181e34811

Here are some better options of static stretching: a general cardio warmup (same benefits), sport/activity specific drills (prime your body for what it is about to do by moving it, under control, in the ways it is likely about to move), eccentric lengthening (applied the same, if not better stretch with the added benefit of strengthening), or lifting weights! Despite poorly supported theories regarding “Strong” muscles being short/tight, weight lifting has been shown to improve flexibility just as much as static stretching. So why not use your time more efficiently and get strength benefits for the same time cost as stretching?
O;Sullivan K, et al. The effects of eccentric training on lower limb flexibility: a systematic review. BR J Sports Med.2012;46(12):838-45

Furthermore, one study looked at groin strains specifically. If a muscle is irritated, often, our first act I to stretch it. However, this may not be the best option. Strengthening/loading an irritated muscle, specifically the hip adductors in this case, decreased injury up to 46%!
Haroy J, et al. The adductor strengthening programme prevents groin problems among male football players: A cluster-randomized control tria. BR J Sports MED. 2019;53(3):150-157

One last thing. What is the rationale for stretching? To increase range of motion, correct? Well, if you have full range of motion, there really is no rationale to stretch a muscle. Also, what use is it to have a muscle be able to stretch to a certain length passively without having strength and the ability to actively control movement in that range?

In the end, stretching can be encapsulated in the phrase “nothing ventured, nothing gained”. There’s really no risk or downside, other than potentially wasted time.

Too Long Didn’t Read: Let’s keep this short and simple: you probably don’t NEED to stretch and there are better, more efficient, more effective options.

Now here’s the kicker: what we think we know is constantly changing and evolving based on new, better evidence! Therefore, it is always important to have some flexibility with your beliefs as it relates to health. What I presented today is the most current evidence as it stands today and how it should be implemented today. This could change. And when it does, so should our understanding. In healthcare, as it should, our understanding is constantly changing and improving with the advances made in research; ideas that were cutting edge 20, 10, even 5 years ago could prove outdated and incorrect nowadays. In conclusion, be open, be critical, and don’t be afraid to challenge your biases when it comes to your healthcare! Remember, without science, research, and evidence, we may still think that the sun revolves around the earth or that smoking is good for you or you should stuck leeches over your body when you are sick.

Stay tuned until next time when we discuss, modalities, the sacrum, hip alignment, piriformis syndrome, leg length discrepancy, what pain actually is, and other bad science myth busting!

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