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Article By: Andrew Lock

Welcome to another World First.

In this landmark article I’ll explain the flexed spine and neutral spine controversy, how to understand it, and why movement patterns are the key to successful rehabilitation. Let’s begin – There is no joint range that the body naturally has that is bad for you. Yes, and lumbar spines do flex, and for a very good reason. Now it’s time to make like Charlton Heston and strap yourself in for some time travel (except we are going backwards in time).

It’s evolution baby. We are Homo Sapiens. Approximately 300.000 years as our current form and in the multiregional origin model, the evolution of humanity begins about 2.5 million years ago in the Pleistocene era continuing to the present day within a single, continuous species, evolving worldwide modern Homo sapiens sapiens.

Herein lies the key to the flexed spine.

Let’s consider an important key to survival – Calorie Expenditure Minimization (CEM). To survive as a species you need to have mechanisms to minimize calorie expenditure. In nature calories are hard to come by. If you expend too many and can’t replace them you will die. Thus in Hunter-Gatherer Groups the size of the group is limited by the ability of the land, and the group, to obtain those calories. Human physiology has evolved over 2.5 Million years to maximise our survival. One of the mechanisms of CEM is the elastic mechanism of Spinal Flexion!

Hunter Gatherer spinal flexion minimizes calorific expenditure.

Spinal Flexion Calorie Efficiency Mechanism

It has been observed in lab studies that the lumbar muscles are silent when flexing to the ground and in the early stages of the return from the groun (Gracovetsky/McGill). How the body does this is by using the PASSIVE ELASTIC structures of the spine (Ligaments and Fascia) to stretch and recoil like elastic bands. This does not, effectively, use calories. So in nature we flex our spines to reach the ground, turning off the lumbar musculature, to conserve energy. We have been doing this for over 2.5 million years. It helped our ancestors survive. Muscles burn energy, ligaments and fascia do not.

The evolution and survival of Homo Sapiens has depended on CEM. Spinal flexion both passive sitting and dynamic flexion maximizes ELASTIC structures for support wherever possible. We sit in Posterior Pelvic Tilt to hang off our ligaments. We do not use active ‘tight’ muscles to sit in Anterior Pelvic Tilt. That theory is immediately wrong from an evolutionary examination.

This is a clear reason that the VERY STUPID theory, espoused by under educated individuals, that most people sit in Anterior Pelvic Tilt is wrong. Ever since Robin McKenzie revolutionized Disc understanding in the 1960’s every piece of evidence on low back posture and its relationship to disc injury has been shown to be due to POSTERIOR PELVIC TILT. Never mention that normal people sit in APT again. That’s now officially just stupid.

CEM has helped our ancestors survive for at least 2.5 Million years.


Civilization can only occur when excess calorie stores become available. 10,000 years ago the discovery and implementation of agriculture produced a food surplus that led to the formation of the first permanent human settlements. Agriculture led to complex society. It also changed the postural demands upon the human spine. We moved from diverse Hunter/Gatherer dynamic movement patterns to repetitive farming and repetitive food creation patterns. The previously INTERMITTENT spinal flexion became FREQUENT spinal flexion yet our mechanism of spinal flexion has not changed.

That is a flexed spine in 3rd World agriculture.

Since the Agricultural Revolution, we have had The Scientific Revolution, Technological Revolution, and more recently the Industrial Revolution of the 19th century. This correlates with calorie availability supporting huge world population growth and higher life expectancies. We have now entered the Information Age which has necessitated massive increases in static posture demands. We start sitting as children in front of computers from pre-school to high school, and beyond to seated employment or further education. Social lives are often glued to social media screens as well. Only some of us actually exercise, and the rate of current low back pain, worldwide, is approximately 90 percent in all adults!

This is a slumped 21st Century work posture (Posterior Pelvic Tilt).

Evolutionary spinal mechanisms have not changed, but the way we live our lives today certainly has. We are still using the same mechanisms of calorie efficiency in spinal movement as evolved 2.5 million years ago.

We naturally flex our spine to sit. When we move to pick things off the floor, we don’t use muscles as much as ligaments and fascia to do this. As we are no longer Hunter/Gatherers, and do not vary our postures as much as our ancestors did, we overuse a mechanism that was supposed to be intermittent, not constant. In nature spinal flexion was natural, in modern (Agricultural/post agricultural) society it is overused and abused. Evolution has not caught up with our rate of change, nor has it any reason to (but that’s another story involving the mechanism of evolution).

What about muscles?

Muscles are used where demands are higher, and calorie expenditure is required. In our primal history muscular systems were turned on when tasks demanded more complex movement patterns and heavier loads. In order to lift a heavy weight from the ground (like your Wooley Mammoth steak) you flexed your spine and used muscles to complete the task of returning to upright. This is why spinal flexion is observed in all Conventional Deadlift World Records. You can see this phenomenon on YouTube, where the Lumbar and Thoracic spines are flexed, not in neutral lordosis. This is a maximization of both the passive elastic recoil mechanism (Fascia and Ligaments) and your active calorie expending (Muscular) mechanism.

Let’s face it – this is not a neutral lordotic spine. It’s flexion for all the right reasons.


Further evidence of this need to assume a degree of Spinal Flexion comes from Prof. Adams’ observations that spinal flexion is necessary to UNLOAD the Facet Joints and FULLY load the Vertebral Bodies, which is our most efficient mechanism for spinal weight-bearing.  This is an anatomical fact. We flex our spines out of Lordosis to maximize vertebral loading, via the disc/vertebra stabilizing mechanism (that subject is another 1500 word article in itself).


Let’s look at the next anatomical principle. The Length/Tension Relationship of muscle. Muscle is strongest in its mid-range, not at the stretched or most contracted outer ranges. I have proposed that the flexion of the spine maximizes the erector spinae contractile position and its passive recoil together. I have discussed this with Prof. Stuart McGill, using some of his published data, and he could not find an error in my proposition, but he was cautious in that this was not an area he had deeply considered at that time. (I’ll publish that discussion in a future article).

The graph shows the combined muscle tension and passive elastic recoil effect.


A principle of muscle hypertrophy is that the isometric component of the erector muscle activity has been proposed as the most efficient mechanism for producing erector spinae hypertrophy. This correlates with Prof. McGill’s demonstration that discs are not injured in lifting if the spine is held in a Flexion Moment (Physics principle). Essentially an isometric hold of the spinal position. This is held while the hip extensors produce the torque to make the torso rise.

Here you see that Isometric force (Holding) is greater than Concentric force (Flexing) i.e. don’t lift what you cannot hold in lumbar isometric control is a good rule for learning to deadlift.


There is evidence in abundance that the spinal flexion position is necessary, and safe, if held in a Flexion Moment for maximal lifting.


Welcome to the Modern Day back pain problem. As most people spend excessive hours in spinal flexion, the ligamentous system is overstretched before an act of dynamic flexion (such as picking up your car keys from the floor, or poor form Deadlifting) is undertaken. Failure of the overstretched ligamentous system follows and the disc is exposed to incorrect loading. Failure of the disc structure occurs and the various forms of disc injury are consequent.


No longer do we need to fear finding enough calories. Reeducating ourselves from calorie minimization patterns to active calorie expending patterns IS the solution.

This is where much of ‘modern’ low back treatment is useless. Treating the pain, and not the cause, of low back injury has created a self-perpetuating, self-interested, multi-billion dollar industry.

A large part of the solution is to learn to Hip-Hinge to flex, rather than passive spinal flex. This is an active muscular strategy involving isometric control of the lumbar spine and active use of the hip musculature.


Let’s briefly cover the work of Panjabi. He described the ‘Neutral Zone’ Theory. It is a fact that when a ligament (such as a spinal ligament) is damaged it decreases its ability to hold the spinal segment efficiently. As such, Panjabi suggests that we need to use muscular activity to now hold the segment and make up for the laxity in the ligament.  We have devised many strategies to create this muscular stability. The approach to rehab of isometric holding of the neutral spine with muscular core mechanisms and perfecting the eccentric/concentric hip-hinge is a protective strategy necessary to counter the evolutionary, by default, passive spinal flexion program.



In nature we have passive spinal flexion as our primary movement pattern to pick things off the ground. In the 21st century we need to address this by teaching active muscular static postures and dynamic movement patterns (Good lordotic sitting posture, and hip hinging when flexing).

In high level sport (such as Deadlifting World Records) loaded spinal flexion (not end-range, nor neutral lordosis) creates the mechanism by which the spine bears loads greatest. This is a skill that has to be learned. I was fortunate to discuss this with Ed Coan. I proposed that it takes at least a year to learn to Deadlift safely before being allowed to try a PB. Ed suggested it takes 3 years to learn excellence in technique. We were both talking about at least 3x per week Deadlifting.

IT DEPENDS (Borrowed from Prof. McGill)!

In my approach to spinal rehabilitation I evaluate all the above. Every case is different, but this article underpins much of the explanation of the modern back pain epidemic. Teaching correct movement pattern progressions of strength rehabilitation skills is not understood by many health professionals, yet it is the revolution that will solve our health industries inability to prevent ongoing back pain episodes for individuals.

The assessment and hypothesis testing necessary to make each program individual and to clearly define success as it pertains to each person’s life are the principles that underlie much of what I teach to health professionals attending my courses.

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