The myths of Physiotherapy: “I’m out of alignment, can you crack me back into place?”

Do physiotherapists crack backs? Many people ask this when they say “I’ve put my back out” or “I’m out of place or alignment” and then ask to be put “back in place”. Your belief in this happening depends on your previous experience of Physiotherapy, Osteopathy, Chiropractic.

When I proceed to tell patients that these things don’t really happen in the human body, they will say “but such and such says it does and they cracked my back and I was back in place again and my pain went away”. In fact, 33% of people believe that cracking your spine is mechanically re-aligning the joints or putting them back into place according to Demoulin et al (2018).

Crack your neck

Now I’m not saying that the treatment doesn’t help. It does reduce pain & increases range of movement but it didn’t crack you back into place for sure!

I’m not saying things can’t be out of normal anatomical alignment because they can but they generally don’t move in and out quickly and sometimes they will never change. A person’s alignment is down to lots of factors such as bone size and shape, joint surface contours, ligament shortening or laxity, muscle imbalance to name a few. Obviously, you can’t change some of these things and others you can, but they won’t change quickly for certain.

Another thing is that muscle moves your joint positions and when you are in pain then the muscle will spasm and contract, which will move your joint position just like if you contract your bicep then your elbow will bend but nobody would say that a bent elbow was out of alignment. It is simply in a different position.

So if a treatment lowers pain, then spasm drops and the muscle stops pulling the joint into that position so it is easy to think this is being “put” back into alignment or place but this isn’t the case and it doesn’t even matter. All that does is that symptoms and function restores.

So what is the noise then?


Interestingly the noise you hear during manipulation is called cavitation, which is a sudden decrease in intracapsular pressure that is caused by dissolved gasses in the synovial fluid of the joint being released into the joint cavity. The noise is thought to be a combination of the pressure release and the elastic recoil of the synovial capsule as it snaps back.

If it doesn’t crack me into place then what does it actually do?

Increased mobility and range of movement:
After the manipulation, the synovial fluid in the joint is less viscose, which makes the joint more mobile because the gasses released from the synovial fluid make up about 15% of the joint volume (Brodeur 1995). The gas removed is not reabsorbed for 20 to 30 minutes and this is why you won’t be able to get another crack until after this time (Unsworth et al 1971).

Clark et al (2011) found that the manipulation actually down-regulates the sensitivity of muscle spindles and other segmental sites of the (Ia) stretch reflex pathway, which lowers muscle tone and tension.

Pain relief:
Due to the relaxation of muscle spasm from the above effects, the pain levels reduce.
Manipulation also impacts primary afferent neurons from paraspinal tissues, the motor control system and pain processing (Pickar 2002).
Another effect of manipulation is an endorphin release, which is one of your body’s feel-good hormones, so you feel better afterwards (Vernon et al 1986).


Here is a great mobility exercise that commonly can commonly crack your own back:


Finally, there is the placebo effect:

This is always present in any treatment but it is not equal to all treatments. Due to the fact that a manipulation sounds impressive and the technique is touted as being this miracle cure, then expectations are high and this has been proven to create a greater response. Linde et al (2007) found a significant association between better improvement and higher outcome expectations with placebo treatments.

Now don’t get me wrong if something works, no matter the reason then I’m all for it. Why shouldn’t we try to use the placebo effect to our advantage? After all, it is probably the most effective thing we can cause. The problem is that some practitioners are misleading their patients by making up stories that sound impressive to rationalise their treatment. Some would call this unethical and some might be right and this is why we try to be as guided by the science here at Hawkes Physiotherapy as possible!

There is evidence that this doesn’t happen in the long term from a manipulation. Obviously, there is movement but this is a temporary effect only.

de Toledo (2019) and Tullberg (1998) looked at the effect of a Sacroiliac joint (SIJ) manipulation on the SIJ position and it did not alter after performing the manipulation. What is interesting is that the SIJ only moves a tiny amount anyway but some people often say I feel like my SIJ is out. This is actually not possible but they do feel something is wrong but it won’t the that their SIJ is out.

Now even if the alignment could be changed does it matter?


Not in all cases! For example, Preece et al (2008) found variations in pelvic morphology that will significantly influence measures of pelvic tilt & innominate rotational asymmetry. The angle of the normal pelvis showed that the ASIS & PSIS ranged from 0 degrees up to 23 degrees, which highlights 2 things, it is difficult to measure someone’s pelvic alignment and the range of normal is large.

Also in normal people, 96.7% were found to have a difference in leg length (O’Brien et al 2010), which is nearly everyone. Don’t get me wrong certain amounts of mal-alignment in certain circumstances can be a problem by altering their biomechanics but if the patient has a true difference then manipulation isn’t going to change this. Knutson (2005) believes that anatomical leg-length inequality does not appear to be clinically significant until the magnitude reaches 20mm.

Needham et al (2012) Found that there were only minimal differences in movement patterns of the lumbar spine when comparing normal to a 3 cm leg length discrepancy. Another paper found that there is no evidence of an association between leg-length inequality & greater trochanteric pain syndrome (Segal et al 2008). However, this review found heel lifts or raises reduce low back pain in leg length inequality but they didn’t compare to a placebo heel lift/raise (Brady et al 2003).

Obviously, research can only partly answer this, as in my experience I have seen some people put a 5mm raise in their shoe and it works wonders and other people with no problems in spite of significant differences.

When you consider the amount of time that practitioners talk about spinal alignment and symmetry, the evidence does not actually support an association between sagittal spinal curves & spinal pain (Christensen & Hartvigsen 2008).

MRI scans, which are considered to be very accurate actually show that the ‘normal’ alignment and structure doesn’t exist a lot of the time. For example, it was found that 70% of pain-free hockey players were found to have abnormal pelvis or hips on MRI (AOSSM 2010).

Does the pop have to occur for manipulation to be effective?

No – Sillevis & Cleland (2011) found that there were no significant differences in pain reduction in the subjects who experienced an audible sound compared with the subjects where the sound was absent.

Is manipulation safe?

Risk is low, between 1925 & 1997 there were 177 cases of neck injury associated with neck manipulation, at least 60% were done by chiropractors (Fabio 1999). Considering the time frame this is a low rate but as you can see there is a risk. Haynes et al (2012 found that conclusive evidence is lacking for the association between neck manipulation & stroke.

Risk of manipulation causing a worsening lumbar disc herniation or Cauda equina syndrome is less than 1 in 3.7 million (Oliphant 2004). So overall risk is low and nothing in life exists without risk, just as long as you are aware that there is a risk then you can make your own decision.

How effective is ‘cracking your back’?

Temporomandibular syndrome (TMJ) – NO, There is not sufficient evidence to support the effectiveness of the mandibular manipulation therapy for TMJ syndrome (Alves et al 2013).

Cervicogenic headaches –  YES, Cervical manipulation and mobilisation with cervico-scapular strengthening were most effective for decreasing pain outcomes (Racicki et al 2013).

Neck pain –  YES, Cervical manipulation & mobilisation produced immediate short-term improvements in neck pain and Thoracic manipulation is effective for immediate pain reduction compared to placebo for chronic neck pain (Gross et al 2010).
Thoracic Spinal Manipulation has a therapeutic benefit to some patients with neck pain compared to other interventions (Huisman et al 2013).

Low back pain, YES, Exercise with manipulation is likely to speed up & improve outcomes & minimise episodic recurrence with low back pain (Lawrence et al 2008). Hypomobility (reduced movement) in the lumbar spine is 97% likely to benefit from lumbar spinal manipulation (Cleland & Koppenhaver 2005). There is short term benefit over placebo for manipulation in acute to subacute low back pain (Hidalgo et al 2014). Based on the findings of this systematic review there is evidence to support the use of spinal manipulation (Kuczynski et al 2013).

Lower back pain with leg symptoms (Sciatica) – YES (but careful), Spinal manipulation is an option for symptomatic relief in patients with lumbar disc herniation with radiculopathy (Kreiner et al 2012).

Chronic Low back pain – YES (but only short term), There is short term benefit over placebo for manipulation in Chronic low back pain (Hidalgo et al 2014).


Back to the very first question, “Do physiotherapists crack backs?”

Yes as manipulation can be effective, certainly in the short term. It is a relatively safe technique if done correctly on a suitable patient. More specifically manipulation helps to lower pain and increase range of movement. This technique temporarily improves pain and range of movement just like a massage can and these are treatments that we perform on certain patients at our Physiotherapy clinics in Stoke on Trent, Staffordshire. So yes Physiotherapists can crack backs but one thing that it doesn’t do is realign you! It doesn’t have to make a noise to be effective and overall if you want long term benefit, then the correct exercises are needed.

So next time someone says that you are out of alignment and ‘this’ technique will ‘crack’ you back into place… RUN!

If you need any further information or would like to book an appointment then call Hawkes Physiotherapy on 01782 771861 or 07866 195914.


The content in this blog article is provided for general information purposes only and is not meant to replace a physiotherapy or medical consultation.

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Online Physiotherapy

Put simply this is Physio done via either telephone or video over the internet. Skype and facetime are examples of this.

Contrary to popular belief online physiotherapy can be very effective and it can help the same injuries that face to face physio can help. I have helped many people with injuries such as disc prolapses, tennis elbow, neck pain and much more).