How Much of Manual Therapy Is Mechanical, and How Much Is Neurological?

A Debate Often Framed as Either/Or

Discussion of how manual therapy works frequently gets framed as a binary choice: either it produces genuine mechanical change in tissue, or its effects are "merely" neurological and psychological — a framing that, on closer inspection, turns out to be a false choice.

A Model That Treats Both as Part of One System

An influential and widely cited comprehensive model of manual therapy's mechanisms proposes that mechanical force applied to tissue is simply the initiating input — what actually produces the clinical effect is a resulting cascade of neurophysiological responses at the peripheral, spinal and supraspinal level, alongside psychologically mediated factors like expectation and reduced fear (Bialosky et al., 2009). Mechanical input and neurological response are not competing explanations; the mechanical input is the trigger, and the neurological response is the mechanism.

Where the Weight of Evidence Currently Sits

The forces manual therapists can generate by hand are generally too small to produce lasting, plastic deformation of connective tissue, which weighs against a purely mechanical account of lasting change. At the same time, measurable, biologically real local tissue effects — changes in microcirculation, inflammatory signalling and tissue perfusion — have also been documented. The most defensible current position treats manual therapy's clinical effect as predominantly, though not exclusively, neurophysiologically mediated, built on top of a genuine but more modest local mechanical and biological foundation.