From time to time one might read about concerns that manipulation of a person’s body could be dangerous due to the way forces need to be applied. However in trained hands the application of a well practised high velocity thrust is safe. This is why the professions of Chiropractic and Osteopathy have registers of competent persons able to apply manipulative forces safely to the human body. Even when it is in pain.
In 2018 a study (1) looked at the forces imparted to the spine during a typical Chiropractic manipulative procedure, it followed other work that showed the typical force required to fracture the spine, forces generated in bending forward and straightening back up and the forces generated in minor falls and bumps in the car.
Someone running into the back of your car whilst you are stopped at traffic lights could generate forces into your body of 7000N from just a 15mph impact force (delta-V) (2). Forces between 380N and 760N of an oscillating nature were able to fracture 70% of spines tested (2). A factor of ten less than a 15mph one off impact. A cartoon classic of falling onto the base of the spine from a standing height has been shown to produce forces up to 940N on a hard floor, quite a bit more than the tolerance of the spine to fracture at 340N (3).
The forces of manipulation were measured and found comparable to the forces of mobilisation. Without adequate evidence of the extra safety of mobilisation, manipulation is taught to students of manual therapy as the pinnacle of interventions for muscle aches and joint pains. Thus there is much ego about the delivery of manipulation over mobilisation in the physical therapy world.
The 2018 study results showed a force delivered in a high velocity thrust to be 30N to the facets, supraspinous ligament and or the intervertebral disc (1). Similar to the forces delivered in mobilisation, in regular moving around changing postures and much less by a factor of ten than injurious forces imparted to the spine from falling over or through a whiplash trauma. No need to be scared that a Chiropractor will push too hard!
In the courtroom a distinguished expert and Professor of Complementary Medicine at Exeter University, famously known for being anti-manipulation, testified that not even neck manipulation resulted in ‘harm’ (4).
1. Funabashi M et al (2018) Journal of the Canadian Chiropractic Association Dec 62 (3) 130-142
2. Arthur Croft (2009) The Biomechanics of Spondylolysis Part 1. Dynamic Chiropractic (Sept) 27 20
3. Van-Toen C et al (2012) Transmission of Force in the Lumbo-Sacral Spine during Backward Falls. Spine (Apr) 37 (9) E519-E527
4. O’Loughlin v Grieg  EWHC (QB) (Lexis Citation 3125) P.9 para 8