Each of the 5 standard instructions is partly right, and the book names the mechanical piece each one leaves out
Chapter 3 of the Spinal Fitness book lists 5 instructions most people have been given for their backs: sit up straight, lift with your legs, strengthen your core, stretch what feels tight, and use better ergonomics. The book states that none of them is useless and that, by themselves, they are incomplete, and it replaces them with 1 rule: "Restore the curve. Shorten the resistance arm. Reduce shear."
Chapter 3 states that this instruction does not explain how the pelvis, rib cage, head and spinal curves manage force. Chapter 1 gives the chain the instruction skips: when the pelvis rolls back, the lumbar curve flattens; when the lumbar curve flattens, the thoracic spine rounds; when the thoracic spine rounds, the head drifts forward. Each inch of forward head position adds approximately 10 pounds of effective load to the cervical spine. The book's approach addresses the source of that chain, the pelvis: when the pelvis stays neutral, the spine keeps its S-curve, the resistance arm shortens and the muscles do less work to hold the body upright.
Chapter 2 states why the instruction does not hold. It may work for a few seconds, but it does not change the posture the body has been practicing for years; without the curves, strength and control to support the position, the body collapses again. Its rule: "Under fatigue, the body does not choose the best posture. It chooses the most practiced posture." Chapter 4 adds a second problem: "stand up straight" can be misleading, because a spine can be straight and still mechanically disadvantaged. The book's target for the spine is not straightness but proper curvature.
Chapter 3 states that this instruction does not explain the resistance arm, the fulcrum, or how far the load is from the spine. Chapter 1 gives the lever arithmetic: mechanical advantage equals effort arm divided by resistance arm, and in the spine the effort arm, the spinal muscles, stays fixed and short. That leaves the worker 1 variable to control, the resistance arm, meaning the distance between the spine and the load. When the box is in front of the body, the spine operates as a long lever, and the back muscles must generate enough force to stop the collapse, which creates high compression and shear at the lumbar discs.
The book's setup for the lift is a stacked system: feet under the load, hips hinged back, spine neutral, and the box pulled close before the lift begins. That shortens the resistance arm, transfers the demand to the hips and legs, and shifts spinal loading from shear toward compression. Its 3 cues are "Keep the load close. Hinge at the hips instead of the spine. Stay stacked." and the book states that these are lever mechanics, not posture rules. Chapter 5 adds that if the worker must lift and then press forward, the body has to move from lifting the load to driving it forward, and a proper S-shaped structure lets force move through the trunk rather than collapse into it.
Instruction 3, in Chapter 3's account, does not explain whether the force being created is helping the joint or increasing shear. In the book's mechanics, a contraction that drives force into compression stabilizes a joint through bone geometry, and a contraction that adds shear demands stabilization from ligament, disc or more muscle. The book's sit-up example in Chapter 5 shows the difference: a person lying flat with the lumbar curve flattened has no fixed reference point for the lumbar spine, and the movement may train compensation instead of alignment, while the same sit-up over a correctly placed fulcrum trains the abdominal-lower back complex through a range that promotes the S-shaped spine.
Instruction 4, in Chapter 3's account, does not explain why the tissue tightened in the first place. The book's explanation is that the nervous system tightens tissues to create stability when structure is missing, so the tight muscle is not always the problem. Chapter 5 applies it to the hamstrings: they may be overloaded because the spine has lost the structure that keeps the trunk balanced over the hips, rather than short because they need stretching. Chapter 1 adds that if the underlying curve and segmental control are missing, the nervous system chooses protection over perfect form every time.
Instruction 5, in Chapter 3's account, does not explain that the worker's structure still determines how force is distributed. Chapter 1 describes standard workplace programs as reducing load weight, adjusting workstation height and changing equipment, calls those useful steps, and states that they do not address the root cause: the spine operating as a long lever with a long resistance arm. For pushing, the book makes the same point about handle height and load weight: a stacked body transfers force into the cart, and a collapsed body absorbs more shear.
Chapter 3 summarizes its principles as 3 actions. Restore the curve means rebuilding and preserving the spinal shape that gives the body mechanical advantage. Shorten the resistance arm means keeping loads, head position, trunk mass and work demands closer to the spine. Reduce shear means arranging posture and movement so force travels through the joints instead of sliding across them. The book applies the rule to 8 settings: sitting at a desk, driving, lifting boxes, pushing carts, carrying tools, training athletes, recovering from injury and aging with independence.
Chapter 3 states its goal for the reader as not to memorize biomechanics but to understand enough physics to stop blaming the body for responding logically to poor force conditions. The system it uses to carry the rule out combines 3 elements: support through fulcrum positioning and setup, controlled movement that teaches the spine to organize force, and appropriate resistance and progression.
Pain, numbness, tingling and dizziness are the stop signs in the Spinal Fitness book. When one appears, stop the exercise, get evaluated, and then proceed with a therapeutic exercise program designed by a Spinal Fitness expert. The book's training rule for every step is that strain is acceptable and pain is not.
The Back Trac roller is Step 1 of the 5-step system, and the PowerCushion is the fulcrum for the Pelvic Tilt and the Sit-Up.
Practitioner Eileen Durfee, NBS (Nutritional Balancing Science), NASM-CPT - wellness educator, inventor, author, and a Nationally Certified Spinal Fitness Specialist.
The Neck Flexion chapter of my book carries a photo caption of Leigh Steinberg, the real-life inspiration for Jerry Maguire, during his first Back Trac rolling session, with the result the book records: "measurable restoration of cervical lordosis" after 1 session.
Our Facebook group is free to join for questions about any of the 5 steps in the Spinal Fitness system.
The book calls it incomplete. The real goal is to keep the resistance arm short by keeping the load close to the spine, with the feet under the load and the hips hinged back.
The book states that the instruction works for a few seconds but does not change the structure the body has practiced, and under fatigue the body returns to its most practiced posture.
No. Chapter 4 states that a spine can be straight and still mechanically disadvantaged; the goal is proper curvature.
1 rule: restore the curve, shorten the resistance arm, reduce shear.
No. It calls ergonomic changes useful steps that do not address the spine operating as a long lever with a long resistance arm.
Published October 28, 2026 - Updated October 28, 2026
By Eileen Durfee, Nationally Certified Spinal Fitness Specialist, NASM-CPT, and author of the Spinal Fitness book.
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Eileen's free guide, Is Your Posture Aging You?, on EileenDurfee.com
