Flatten your back they said..
Flatten your back AKA “posterior pelvic tilt”
If you really want to get on my nerves, be an educated clinician and give the most general advice possible, like this to people looking for help. Your spine should never be flat, as a matter of fact a flat back is usually a back that is in pain. Your spine is designed to have very distinct curves and if you would like an idea of what it feels like to mess with these curves ask your friend with legitimate scoliosis how they feel. Too many experts of all things out there trying to flex their mental on something so complex is truly disappointing and frustrating .
One of the reasons this tip seems to be so wide spread is because people think that it is a way to avoid pain. Avoiding pain is a good thing right? The problem with this philosophy is that avoiding pain in this case can be a trick. When thinking about pain and your body it is important to realize that your body can be tricked by temporary relief, in reality it’s probably your mind being tricked. A posterior pelvic tilt flexes the lumbar spine by default, flexion of the lumbar spine compresses the anterior portion of the disc which causes the disc material to travel backwards where you have now created more space. More space = less compression = magical cure = STFU! The problem with this equation to pain relief is that if you happen to be someone that has discogenic issues flexion based movements often perpetuate the issue by straining the ligamentous structures your spine relies on to keep everything in place. Excessive stress from poor body mechanics combined with exercising and forcefully flexing these segments can lead to more material where nerves should be able to move around freely.
True spinal health can only be accomplished by finding balance between the muscles of the front of your body and those of the back. When you flatten your spine out you are flexing the spine which by default relaxes the muscles of the lumbar spine. I do not know many people that need their lumbar paraspinals to just relax. In reality most of us have weak lumbar stabilizers because we sit too much and these muscles tend to get elongated and weakened.
What is the perfect form? There isn’t one, sorry. Everyone has variability within their individual anatomy so everyone will require varying degrees of contraction to counterbalance the forces experienced throughout the day. This is where being able to listen to your body becomes increasingly important. Something that can be helpful pelvic clocks. This exercise will involve some posterior pelvic rotation but it will not be sustained and it will not involve any hip flexion which will minimize flexion forces through the spine. This exercise can be used to get the motions down and to understand where your neutral is.
A neutral spine with balanced contraction provides your body a solid base to work from. This can prevent injury, improve performance, and ultimately ensure your able to enjoy staying active throughout a long and healthy life! When performing any strengthening exercise you should be able to adopt this neutral position and control the forces that are being applied through the spine. If you feel your back begin to flatten or arch from this neutral you need to determine why this is occurring and address it before it leads to excessive strain on the spinal structures.