Active Craniospinal Tensioning (ACT) for Posture Correction and Spinal Decompression: Biomechanical Rationale for Glymphatic Clearance and Cerebral Venous Preconditioning (CVPC).

For approximately two-thirds of each 24-hour period, the upright human spine bears a continuous gravitational load; yet no common movement or exercise naturally produces meaningful axial decompression of the entire spine. Active craniospinal tensioning (ACT) addresses this unmet need through a brief, self-administered squat maneuver against an overhead anchor, intended to generate reproducible axial spinal decompression without specialized equipment. This report, which extends a previously published series on axial spinal traction, presents ACT as a postural correction and spinal decompression intervention. Building on those findings, a second distinct hypothesis is advanced: that two transient physiological events occurring simultaneously during the maneuver may together acutely accelerate glymphatic clearance. The first is a cerebrospinal fluid (CSF) pressure gradient generated during traction and rapidly reversed upon release, as detailed in the previous technical reports; the second is suboccipital venous occlusion during the tensioning phase, followed by a rebound upon release. The second mechanism, suboccipital venous occlusion-rebound, is further proposed as a novel venous-side modality for cerebral venous preconditioning (CVPC), distinct from existing arterial-based ischemic preconditioning approaches, whether local or remote (e.g., remote ischemic preconditioning (RIPC)). Diffusion tensor image analysis along the perivascular space (DTI-ALPS) is proposed as the primary falsifiable endpoint for the glymphatic clearance hypothesis, which does not itself test the separately proposed CVPC effect of suboccipital venous occlusion-rebound. If confirmed, this endpoint would support glymphatic clearance as an additional mechanism of ACT, positioning ACT, alongside its proposed roles in posture correction, spinal decompression, and cerebral venous preconditioning (CVPC), as a brief, self-administered maneuver addressing multiple physiological targets through daily applications totaling less than one minute, without specialized equipment or clinical access.