LEARN / THE FOUNDATIONS
Clear explanations of posture, mechanical loading and everyday care. Start with the questions that matter to you.
01 / POSTURE
Your body continually organises and adjusts to gravity, movement, the task and its surroundings. A photograph captures one moment in that process.
Dr Shahar uses Perpetual Posture™ to explain this ongoing process. The idea makes room for movement, support, task changes and rest.
02 / MECHANICAL DEMAND
A load farther from a chosen joint creates a larger turning effect. A surface can share some of its weight. Your body’s own parts have weight too, so changes in their position change mechanical demand.
Better Load Sharing™ is Dr Shahar’s teaching framework for considering how demand is distributed across structures and over time. Better sharing depends on the task and the person; it need not be equal.
Same bag. Bringing it closer reduces its leverage.
Turning effect = unsupported weight × horizontal distance. Here, 5 kg × 9.81 m/s² gives about 49 N. At 15 cm the external moment is 7.4 N·m; at 45 cm it is 22.1 N·m. The support option assumes an upward force equal to half the bag’s weight acting at the bag.
This simplified model excludes arm weight, movement and muscle leverage. It does not calculate spinal load, actual muscle force or injury risk. Read the mechanics source: OpenStax, Torque.
03 / CAPACITY & RECOVERY
Mechanical loading helps stimulate tissue adaptation. The response depends on the tissue, the amount and pattern of loading, the person and recovery. Training intentionally increases demand to develop capacity.
When demand exceeds what a tissue can tolerate and recover from, excessive loading can contribute to tissue damage, pain and loss of function. These outcomes do not have to occur together or in a fixed order.
Understanding mechanics does not allow us to predict an individual’s injury or symptoms from their posture alone.
A 12-month randomised trial examined how a specific forearm-loading programme affected bone adaptation in adult women. It supports a relationship between loading dose and adaptation in that setting; it does not demonstrate that a posture cue prevents spinal degeneration. Troy et al., 2020.
Experimental tissue studies can demonstrate injury mechanisms under particular loading conditions, but they cannot supply a universal safe or unsafe posture for ordinary life. Callaghan & McGill, 2001, porcine disc model.
For the distinction between pain and tissue findings, see Pain and structure.
Dr Shahar’s philosophy of making ongoing musculoskeletal care part of life, before pain becomes the only reason to pay attention.
A framework for addressing modifiable demands and building capacity. A preventive benefit must be assessed for a particular intervention and outcome; the name itself is not evidence of prevention.
Sources checked 1 November 2026 · Research and references
