Sitting shortens the hip flexors. I have read this headline so many times. What I haven’t seen is evidence. It’s one of those claims that no one seems to question.
They say that tight hip flexors (from sitting) is one of the most commonly seen muscle imbalances causing lower back pain, but this association has also been mentioned in non-sedentary individuals such as runners and athletes. Sitting for prolonged periods of time is probably the most popular theory of how the hip flexors get tight. Nevertheless, does sitting really affect the hips?
Hip Flexor Length and Sitting
No muscle has been more misunderstood and has more dysfunction attributed to them than the psoas muscles. Much like the gluteus maximus, the psoas major is attached to a number of structures mainly the spine, pelvis and hip. The psoas major originates along the sides of the spine (starting at the transverse processes of T12 – L5 vertebrae) and inserts into the hip (lesser trochanter of the femur). It is considered a spine, hip and pelvis stabilizer.
Even within the biomechanical model, it is worth noting that the psoas exerts an eccentric contraction, which is a confusing way of saying that the psoas doesn’t shorten.
Sitting they say, places the muscle crossing the hip at a shortened position (banana-like shape) and becomes tight. This is something that I would question.
Here’s why? The shortening of a muscle or a tissue after a prolonged immobilization is called a “contracture.” Contractures are essentially muscles or tendons that have remained tight for too long, thus becoming shorter. Once they occur, its been argued that they cannot be stretched no matter what. However, evidence says that we can fully prevent the negative effects of prolonged immobilization by stretching for 1/2 hour a day. This goes to show that sitting in a chair for lengths of time with intermittent breaks in between preserved range of motion and muscle length in a muscle that was shortened throughout the day.
From a clinical perspective, most of the patients that I’ve encountered were given a prescription to “stretch” or “release” their hip flexor. Part of the reasoning for such a referral is the assumption that since their back is in pain then it must be their “psoas” or “hip flexor” muscle that needs to be “released.”
In my experience, via a thorough examination and assessment what I usually discover is quite the opposite – a psoas that is not short or tight, but rather elongated and overused. Therefore, additional stretching of this muscle is not useful and may do more harm than good to the patient or athlete.
Adaptation to Sitting
The human body readily responds to changing environmental stresses in a variety of biological and cultural ways. Repetitive and constant sitting may predispose the hip in a flexed position. However, the same can be said about too much extension.
Assuming that you sit on a chair all day long, you would think that the hip flexed position would place your joints in a compromised position. But this does not appear to be the case. Don’t get me wrong, sitting in a chair all day long is bad news (from a cardiovascular standpoint) but it doesn’t structurally shorten tissues.
Here’s why? For instance, animals such as your dogs and cats tend to be in static flexed positions all day long yet they still get out of the sitting or sleeping position without any loss of function or shortening of muscles. Much like humans, upon rising they stretch a little then move on with their activities such as walking or sprinting.
Even if you did sit for a straight, uninterrupted 8 hours a day this isn’t enough to create shortening in muscle tissue. Shortening occurs when you are in a cast, immobilized in someway in a shortened position for prolonged periods. I mean days and weeks. 8 hours ain’t jack. Even with an hour day you aren’t really stuck in that position. You get up throughout the day and stand up, thus interrupting the shortening possibilities. – Greg Lehman, BKin, MSc, DC, MScPT
If you ask side sleepers who sleep in a fetal or flexed position for eight hours at a time, of the more common secondary complaints that you’ll hear isn’t “hip pain” or “hip tightness” but shoulder and neck pain.
Early images of our ancestors revealed that humans didn’t have chairs. If you have traveled to Asia and parts of Africa you will have seen that the squat is still a massively popular position to hang out in. People squat while they use the bathroom, work, eat, and drink. Such position involves far more hip flexion than sitting in a chair. We would like to think that this makes our hip joints and muscles weave its way together to make them tight after a few hours of sitting but this isn’t the case for the natural use of these limbs.
The Real Trouble with Sitting
The trouble with the idea that sitting causes our hips and psoas muscle to be tight isn’t much of a joint or muscle shortening issue. Studies on human and animals revealed that one can stretch for 30 minutes a day up to 6 hours a day to counteract the adaptive shortening of the muscle tissue.
Although no studies have been done on the association between sitting and hip flexor tightness, one must invest in activities that promote hip extension (opening) and glute strengthening.
Sitting in a chair for prolonged periods of time isn’t what nature intended for the human body. The worse part about sitting isn’t about hip tightness, fat or obesity. It has more to do with your cardiovascular health. The link between sitting and cardiovascular disease has to do with the physics of how blood flows to your arteries (read about it here, here and here).
According to a biomechanist named Katy Bowman, plaque accumulates NOT because of blood chemistry but because of the action of the cells flowing within the blood vessels. Normally, blood cells will roll along blood vessels like a bowling ball down a hallway, if the hallway (blood vessel) has a turn in it (e.g. sitting position), the ball will smack into the wall. Blood cells do the same thing.
You have to stop the wounding, which means you have to fix the geometry (positioning). It’s really about the micro-mechanics and geometry. If you are not aligned correctly, you are creating damage on the cellular level. – Katy Bowman, M.S.
A blood cell hitting the wall of an artery leaves a wound. Similar to getting a cut in your hand, a scab forms over time. Scabs in the arteries use cholesterol to seal the wound. That’s why cholesterol isn’t the problem – it’s the wall wounding.
There is plenty of epidemiological evidence linking sitting time to various chronic diseases and linking breaking sitting time to beneficial cardiovascular effects, but there is very little experimental evidence. We have shown that prolonged sitting impairs endothelial function, which is an early marker of cardiovascular disease, and that breaking sitting time prevents the decline in that function. – Saurab Thosar, PhD researcher OHSU
Our body is equipped to handle all sorts of twists and turns along with maximizing pressure gradients to keep the flow smooth. The bad news is that artery geometry changes with structural positioning.
The twists and turns created by chronically bending joints for excessive bouts of time a day is like adding a wall in your hallway. Prolonged sitting does that.
What Can You Do?
For a more complete approach, I usually recommend dynamic stretches that cause hip extension along with strengthening the gluteus maximus (aka “butt” muscles). Some examples would be:
Bottom Line: Sitting may cause your hip flexors or “psoas” to get tight or stiff, but it appears that there isn’t much scientific evidence to prove that they do. On the other hand, there are more pressing issues that you need to consider rather than just muscle length. If you are looking to avoid the negative effects of sitting from a cardiovascular standpoint and messing up human movement then it would be wise to invest on: protecting your structural health via structural chiropractic or physical therapy, a gym membership, taking hourly 5-minute walks and asking your boss to buy you a standing desk.
Have a GREAT day!
…Dr. Brian Tiu & the Elite Chiropractic Team
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- Study Bolsters Link Between Heart Disease and Sitting: Amer College of Cardiology
- Differences in Brachial and Femoral Artery Responses to Prolonged Sitting: Cardio Ultrasound
- Blood pressure and blood flow during postural change: J Appl Physiol
- Effects of gravity on venous return: Cardio Physiol Concepts
- The stabilizing system of the spine: Panjabi, J of Spinal Dis
- Energy transfers in the spinal engine: Gracovetsky, J of Biomed Eng
- Are you sure your hip flexors are tight? If so, why and who cares? Greg Lehman
- The importance of hip flexion strength: Chris Johnson
- Reflex activation of gluteal muscles in walking: Janda, Spine
- Hourly 5-minute walks reverse arterial damage caused by sitting: Medical News Today
- Standing during meetings may improve work performance: Medical News Today
- Walking boosts creative thinking: J of Experimental Psychology
- Reduce time sitting to protect aging DNA: British Journal of Sports Medicine
- What are the best glute exercises? Bret Contreras
- Sit too much, and your blood vessels, will kind of, sort of turn into stones: Amer Coll of Cardiology
- Does excessive sitting shorten the hip flexors? Todd Hargrove, Better Movement
- Sitting and tight hip flexors: James Speck, Somastruct
- If you do any psoas or releases to your abs, you must read this: Physiodetective