The Need For Speed!

The concept of using a drop piece for adjusting was created by Dr. J. Clay Thompson., who stumbled across it almost by accident, creating what is now known as Thompson technique. Today Chiropractic drop piece adjustments make up a proportion of many other techniques such as SOT, Logan, Diversified adjusting, Extremity adjusting and Gonstead.

So what makes drop piece so great? First and foremost, the use of drops allows the DC to create a specific adjustment with the least amount of physical strain on his/her body. Drop piece is also a very gentle way of adjusting for the person on the receiving end. Drop piece also helps to promote efficiency and little to do for the patient, except to relax.

Let’s jump into a little science... How does it work?

The Thompson drop is fully based on Newton’s First law of Motion, which states…

“A body is in equilibrium if no force is acting upon it. If it is at rest, it remains so; if in motion, it persists in motion, unless an opposing force is met.”

This law is what creates the catalyst for low force, high velocity (HVLA) drop piece adjustments. Let’s break it down a little further. The vertebrae is motion as your apply your pretension pressure, the second the bench comes to a stop, the the adjustment is created. The drop provides the opposite force that brings you from a state of motion to a state of rest.

The force that creates the adjustment is thus created by the change in momentum. 

Momentum = mass x velocity

Increasing velocity is one way to create a greater change in momentum when things comes to a sudden stop (which has the momentum of 0). This is how a drop piece adjustment creates a super fast HVLA (high velocity low amplitude) chiropractic adjustment.

Still with me? Ok, let’s keep going…

So, speed is everything and that is the whole point of a drop piece adjustment to create a super fast HVLA  chiropractic adjustment. 

There is plenty you can do to slow down the velocity at which the body part in question comes to a stop, the stand out one is by adding padding. Have you ever tried adjusting someone on a bed? Never goes very well does it. That’s because the momentum of the adjustment is affected and the change in momentum reduced, therefore less force goes into the adjustment. Much of the force is dissipated throughout the padding rather than through your patient. This is the exact reason we added a firmer foam core into the lower end of Belloost™ chiropractic pregnancy pillows. It makes no sense to have a soft padding around the pelvis of a pregnant women, not only does it slow down arguable your most important adjustments for a pregnant lady, it’s also not very supportive and will require you to use more force to manipulate. 

To reiterate… If you slow things down, your adjustment becomes less effective.

Dr Heidi Havvik discussed this in her book ‘The Reality Check’. The speed at which we adjust as chiropractors is key in creating the physiological and neurological benefits of a chiropractic adjustment. A speed of 200m/s is needed to induce a neurophysiological response, which is not found with slow stretch/low amplitude mobilisation type adjustment.

So let's stop slowing down our super duper adjustments. Instead let endeavour to make every adjustment true to their chiropractic roots, delivering maximum efficacy, maximum neuroplasticity and maximum physiological change.

If you use a drop piece in your clinic, a Belloost™ chiropractic pregnancy pillow should be the only choice to allow high quality efficient treatments for pregnant women. You can purchase yours from our online Store today.


Fryer G, Pearce AJ. The Effect of Lumbosacral Manipulation on Corticospinal and Spinal Reflex Excitability on Asymptomatic Participants. Journal of Manipulative Physiological Therapy. Volume 35, Issue 2, Pages 86–93

Dr Heidi Havvik. The Reality Check. 2014