Home Blog Corrective Exercise: Why Stiffness Can Be a Good Thing

Corrective Exercise: Why Stiffness Can Be a Good Thing

Written on April 19, 2011 at 6:35 am, by Eric Cressey

With reference to strength and conditioning programs, the adjective “stiff” is generally perceived to be a bad thing, as folks mean it in a general sense.  In other words, you seem “locked up” and don’t move well.

Taken more literally and applied to specific joints, stiffness can be a very good thing.  A problem only exists if someone is excessively stiff – especially in relation to adjacent joints.  If someone has the right amount of stiffness to prevent movement at a segment when desired, then you would simply say that it’s “stable.”  That doesn’t sound too bad, does it?

This is generally a very confusing topic, so I’ll use some examples to illustrate the concept.

Example #1: Reducing kyphosis.

Take your buddy – we’ll call him Lurch – who sits at a desk all day long.  He’s got a horrible Quasimodo posture, and he comes to your for help with improving it.  You know that his thoracic spine is stuck in flexion and needs to be unlocked, so you’re obviously going to give him some thoracic spine mobility drills.  That’s a no brainer.

However, would you say that Lurch would make better progress correcting bad posture with those drills alone, or if he combines those drills with some deadlifting, horizontal pulling strength exercises, and a more extended thoracic spine posture during the day?  Of course Lurch would do much better with those additions – but why?

All those additions increased stiffness.

With the thoracic erectors adequately stiff relative to the cervical erectors (which create forward head posture when too stiff) and lumbar erectors (create lordosis when too stiff), there is something to “hold” these changes in place.  If you’re just doing the thoracic spine mobilizations, you’re just transiently modifying stiffness (increasing tolerance to stretch) – NOT increasing range of motion!

You know what else is funny?  In 99% of cases like this, you’ll also see an improvement in glenohumeral range of motion (both transiently and chronically).  Mobilize a thoracic spine and it’s easier to create stiffness in the appropriate scapular stabilizers.  When the peri-scapular muscles are adequately stiff, the glenohumeral joint can move more freely.  It’s all about understanding the joint-by-joint theory; mobility and stability alternate.

Example #2: The guy who can squat deep with crazy stiff hip flexors.

A few years ago, one of our interns demonstrated the single-worst Thomas Test I’ve ever seen.  In this assessment, which looks at hip flexor length, a “good” test would have the bottom leg flat on the table with no deviation to the side.  In the image below (recreated by another intern), the position observed would be indicative of shortness or stiffness in the rectus femoris and/or psoas (depending on modifying tests):

In the case to which I’m referring, though, our intern was about twice as bad as what you just saw.  He might very well have had barnacles growing on his rectus femoris, from what I could tell.  But you know what?  He stood up right after that test and showed me one of the “crispest” barefoot overhead squats I’ve ever seen.

About an hour later, I watched him front squat 405 to depth with a perfectly neutral spine.  So what gives?  I mean, there’s no way a guy with hip flexors that stiff (or short) should be able to squat without pitching forward, right?

Wrong.  He made up for it with crazy stiffness in his posterior hip musculature and outstanding core stability (adequate stiffness).  This stiffness enables him to tap in to hip mobility that you wouldn’t think is there.

Is this a guy that’d still need to focus on tissue length and quality of the hip flexors?  Absolutely – because I’d expect him to rip a hole in one of them the second he went to sprint, or he might wind up with anterior knee pain eventually.

Does that mean that squatting isn’t the best thing for him at the time, even if he can’t do it?  Not necessarily, as it is a pattern that you don’t want to lose, it’s a key part of him maintaining a training effect, and because you want him to feel what it’s like to squat with less anterior hip stiffness as he works to improve his hip mobility (rather than just throw him into the fire with “new hips” down the road).

These are just two examples; you can actually find examples of “good stiffness” all over the body.  So, as you can imagine, this isn’t just limited to corrective exercise programs; it’s also applicable to strength and conditioning programs for healthy individuals.  Effective programs implement mobility exercises and self myofascial release to transiently reduce stiffness where it’s excessive, and strength exercises to stiffen segments that are unstable.  Effectively, you teach the body how to move correctly – and then load it up to work to make that education permanent.

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18 Responses to “Corrective Exercise: Why Stiffness Can Be a Good Thing”

  1. Christopher Says:

    A squat to 90 degrees already shortens the psoas significantly. How would a very stiff psoas restrict this ROM (as you say, by pitching forward?)

    I might argue that restricted psoas (length wise) has no effect on squat depth. It makes even more sense to me that an adhesed psoas (reduced force production) might not be able to stabilize the spine from the front, causing lumbar flexion as soon as the descent into the squat begins.

    Any thoughts on clarification?

  2. Jeff Says:

    Chris, I have had the same thoughts. I will be interested in Eric’s take on this. I assumed there was something I just wasn’t smart enough to grasp. I remember Mike Clark discussing increased hip flexion when squatting generally meant a tight psoas. I asked him about it and he didn’t really have an answer. In a bulgarian split squat or rear foot elevated split squat, I can clearly see how a tight psoas on the posterior leg would cause your trunk to flex…..

    Anyway, another thought provoking and informative article by Eric, I don’t know how he does it! I look forward to them every wek. Thanks Eric.

  3. David Shulim Says:

    Deion Sander ran a 4.3 freshman year of college, then his strength coaches saw he had tight hamstrings…so they made them more flexible and he ran a 4.4

  4. Greg R. Says:

    @ Christopher

    “About an hour later, I watched him front squat 405 to depth with a perfectly neutral spine. So what gives? I mean, there’s no way a guy with hip flexors that stiff (or short) should be able to squat without pitching forward, right?”

    I think Eric is commenting more on how the hip flexors were not causing him to come forward or go into lumbar flexion because of the stiffness he had built in the structures that would oppose this unwanted movement. Specifically the core musculature and the posterior hip musculature.

    It’s not so much that the tight hip flexors are preventing squat depth in a sense that the person in question can’t physically get the femur to 90 or below, but that often times when a person with tight hip flexors reaches this depth his body compensates by (tilting the pelvis?) and sending them into lumbar flexion and a forward leaning position.

    Since the pattern in question was the squat he presents kind of a “false stability.” Or to say if you just assessed him on the OH Squat alone, you would miss the issue.

    This is why it’s important to keep him squatting while he lengthens the anterior hip musculature. This will ensure hip stability with newly acquired mobility.

    Meanwhile, he has to add the ROM because as Eric noted sprinting (hip extension) might be injurious to that musculature as the already proven powerful extensors send the hips into extension with a lot of force.

    A good example of his weakness here might be to get him on his back and have him doing psoas holds. The mobility would be there but with out the added stiffness from the support groups as prominent he might find it surprisingly difficult to hold the position past 90 for a good 10 seconds.

    I guess the bottom line is, the tight hip flexors often restrict the squat pattern as a whole not always just the ability to get the ROM in the hips.

    Thoughts, corrections – I put this response up to learn if I understand this as well.

  5. Harrison Says:

    Greatest. Title. Ever.

  6. Bobby Fisk Says:

    Eric – Love the blog. Did this intern make up for the tight hip flexors in other areas and during other movement patterns? and what sport did the intern play that allowed him to be so tight? My experience is basketball players have horrendously tight hips.

    David – I wonder what they considered tight, how much flexibility they added and if he lifted a weight during this flexibility program.

  7. Eric Cressey Says:

    Hey Guys,

    Sorry for the delayed response on this. Wanted to make sure I gave it the time it deserves.

    From what I have seen, when you have chronic restrictions in psoas (or rectus femoris, for that matter), the acquired resting posture in standing is more lordotic (psoas pulls the lumbar spine into extension). More lordosis implies a center of mass (COM) that has been moved forward relative to the base of support (BOS).

    When you throw a squat pattern into the mix, an already forward COM must be counteracted by a shift in the opposite direction – which means a greater hip hinge.

    The only other compensation strategy to avoid tipping over would be going up on the toes, which mechanically repositions the BOS (makes it smaller, but it is shifted forward “underneath” the new COM). So, I guess you could say that this is a relative stiffness issue that also brings the calves into the mix (flexing at the hips/lumbar spine vs. going up on the toes).

    Of course, when you throw adductor restrictions and hip internal rotation deficit into the equation, things get trickier to evaluate.

    Hope this helps.


  8. Sam Leahey Says:


    Observations like this one, only speak to the efficacy of using global movement patterns in our assessments first before attempting to “breakout” isolated movements via table assessments. This is exactly the premise behind the SFMA. Start with global movement patterns (like squat) and breakout via algorithms only the local patterns (like thomas tests) as need. Eric’s observation gives excellent credence to this idea because you can still have great global patterns with imperfect table assessments. And it’s exactly why Gray Cook has said in the past just doing table assessments alone is like collecting trivia, it doesn’t show you what whole functional movement patterns look like.

    Excellent write up, Eric. Very good insights that I wish were discussed more often these days.

    All the best,

  9. Norm Says:


    I agree with your assessment that isolated orthopedic testing is insufficient. Examining the relation of global movement patterns is how to determine the ideal muscle function.

    However, I am still unclear as to how shortened iliopsoas/rectus femoris in this particular case can be deemed “good stiffness.”

    Nonetheless, excellent write-up (along with your many others) Eric and very thought provoking.

    Best regards,


  10. Eric Cressey Says:


    I think you may have misread, as I never meant to say that being short in the hip flexors was a good thing. The point was simply that being stiff in other places could allow one to overcome hip flexor stiffness. Sorry if that was unclear.



  11. Steve Smith Says:

    Great article. One of my co-workers in Florida passed it on to me.

    Agree with Norm’s post completely. Thank you for clearing that up in your reply.

    Stiffness (no matter how you define)/hypertonicity in phasic, multi-joint muscles is never/well rarely a good thing. It clues you in to the fact that there is a insufficiency somewhere else.

    My guess as to the reason the intern in example #2 could squat so well is bc of a significant hypermobility (relative hypermobility) in the lumbar spine/TL junction allowing him to keep his COM over his BOS.

    Glad I got intro’ed to this blog.

    All the best,

  12. Norm Eng Says:


    Thanks for the clarification. I’ll definitely be back to read more of your articles.



  13. Chris Kelly Says:

    Great stuff as always Eric. My two takeaways from this is the importance of assessing global movements first (good mention by Sam above) as well as the importance of concentric, eccentric and isometric training for unstable bodily segments.

    Too often, I think trainers and those in rehab settings forget even isolated strengthening protocols (glute bridges, clamshelss, etc) adhere to progressive loading/resistance and must be integrated back in to global movements to ultimatley cement changes.

    Thanks for waking my brain up this morning.



  14. Justin Sorbo Says:

    Hypermobility in the lumbar spine tends to be an issue with my yoga-loving clients. My first goal is to get the client to realize that “feeling” the lower back during certain exercises is actually a good thing: most of them have totally neglected training the erectors for fear of low back problems.

    Stiffness is essential here!


  15. Luke Says:

    Your description of tight hip flexors and perfect squat sounds like me.

    It’s a curious situation. I still feel like my lower abdominals fail to activate correctly which is what I attribute to the hip flexor stiffness. Having been an australian footballer (lots of running and kicking) and cricketer (stress fractures in my lower back at a young age) would have certainly contributed to the condition.

    I have discovered different movements with the vipr, trx and an australian device called the oov have all helped fire the lower abdominals, while training barefoot in recent months and using the rip trainer through rotation have given me greater glute activation along with some trigger point therapy techniques to release surrounding tissue.

    It’s a work in progress and I’ll continue to try. I wonder if I’ll ever have loose hip flexors. In the meantime I’ll settle for good movement patterns.

  16. Charlie Merrill Says:

    I love the point of this article and am really glad to see you talking about it. Just a clarification about the Thomas test. It can identify 3 things. Anterior hip capsular stiffness, rectus femoris shortness, and TFL/ITB restriction. It does not, as many people think, confirm Psoas muscle shortness. That’s because Psoas doesn’t get short! More and more research shows that Psoas acts as a lumbar spine stabilizer similar to multifidus and transverse abdominus. It’s time for us to stop thinking of the psoas muscle as something that needs to be lengthened. You can read more about it here in an article by Mark Comerford et al., the men pioneering the research:


    Keep up the great work Eric!

  17. Kristian Says:


    I don’t entirely understand the first example. Are you saying that with a thoracic foam roll you are providing the mobility for the T-spine but adding DL’s, horizontal pulls will give the stability to other joints (scapular in this case) at the same time making for a better program because you are increasing mobility where its needed and stability where its needed? I would have thought that if train someone in doing horizontal pulls for instance while they are still quite kyphosed that 1) It would just reinforce the movement of being too flexed into the brain and 2) That it could harm the shoulder joint?



  18. Eric Cressey Says:


    The rolling/thoracic extensions would transiently reduce stiffness to create ROM. Training those strength exercises (or just standing/sitting in better posture) would create better stability in that ROM and help the new stiffness to stick.

    The secret is to NOT allow them to train through poor form. You have to get them into a better thoracic spine position first. If they can’t get there, you regress the exercise and do something else.

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