Pain Science
What pain is, how the nervous system produces it, the three types of pain, the many factors that influence it, and the three-phase strategy for overcoming it (Rehab Science Part I).
What Is Pain?
Pain is a protective experience produced by the brain, not a direct readout of tissue damage. The chapter traces the shift from the Cartesian "pain message" model to the modern neuromatrix view and introduces the biopsychosocial (BPS) model that frames the rest of the book.
How Pain Works
Pain is produced through a loop: sensors in tissues detect stimuli, ascending (afferent) pathways carry information to the brain, the brain builds a unique "neurosignature", and descending (efferent) pathways send back actions and can also block danger messages. Sensitivity is adjustable through neuroplasticity—up after injury and stress, down with graded exposure.
The Different Types of Pain
Three main pain types—mechanical (nociceptive), neuropathic (nerve) and chronic (persistent)— each have recognisable features. Identifying the type, together with the history of onset, guides which protocol to choose and how to dose it.
The Factors That Influence Pain
Pain is shaped by far more than tissue: activity level, movement dose, mental health, beliefs, stress, sleep, diet, genetics and history, culture and meaning, social connection, anatomy, posture and touch. Addressing several factors together works best.
How to Overcome Pain
Whatever the pain type, the strategy follows three phases: reduce symptoms (phase 1), address impairments such as weakness and lost range (phase 2), then build capacity with full-range resistance training (phase 3). Active strategies have the strongest long-term evidence; passive strategies are mainly for short-term symptom relief.