A flat back posture is where the pelvis is turned under (posterior tilt) which causes the lower and upper back to have minimal curvature. This can also have a knock on effect of throwing the head forward.
The normal spine curves naturally in an S shape - in at the neck, out at the shoulders, in again at the waist level and outwards at the base. This shape makes the spine flexible and able to withstand the stresses and strains of everyday life.
We can see from the diagram what happens to the whole body when a flat back posture is developed.
Muscles that become tight and/or short
Muscles that become weak and/or long
The lower back becomes flat or lengthened because the tension in the abdominals and hamstrings along with the weakness in the hip flexors, pull the pelvis into a tucked under position.
With the pelvis in this position the hip joint is continually in passive hip extension. This has the effect of almost switching off the gluteus maximus (hip extensors). Therefore they become underdeveloped and weak.
You do not have to be showing all of the characteristics of a typical flat back posture to suffer from many of the symptoms. Sometimes people will show a very strong posture type but suffer no symptoms, other times someone could present with minimal posture problems and have some very bad complaints.
Therefore always be open to accepting that every case is different.
We should start by looking at the position of the pelvis, trying to increase mobility and gradually adopting a more neutral position.
This is helped by loosening the hamstrings and abdominals and strengthening the hip flexors.
This will naturally increase the curve in the lower back, but you should also look to increase the strength in the lower back muscles to help increase the lumber curvature.
The upper back should also be mobilised and any tension freed up.
The key to correcting this type of posture lies in mobilising the pelvis. The angle at which the pelvis sits directly effects what is above and below it. Do also remember when trying to correct your posture, that it isn’t always easy to identify if the original problem was in the in another area, for example the lower back, and that effected the angle of the pelvis as a consequence. Maybe the lower back muscles were to weak and couldn’t cope with the demands placed on them and therefore the brain worked out that if it shifted the angle of the pelvis it could transfer some of the load onto other more developed muscles.
So the problem would seem, at the present time to be the pelvis not being in a neutral position, but always think about why this has come about. It is not essential to know the original cause, but it does provide a pathway to undo the problems caused.
When learning to adopt a better posture we must always remember to apply our new blueprint to as many positions as possible - Sitting, walking, standing, etc. This reinforces what we are trying to teach our brain and will train the nervous and muscle systems to adapt.
A very good way to mobilise the pelvis is to sit on a fitness ball and rock your pelvis forward and backwards. With the flat back posture type we are wanting the pelvis to adopt more forward tilted position, therefore once you have spent some time mobilising you could sit in the correct position for a few minutes. It should feel like you are sat on the tops of your legs, not on your bum muscles.
One final point to note is - alway concentrate on releasing any tension and stiffness before undertaking any general muscle strengthening exercises.