The Art of the Chiropractic Adjustment: Part VI
SOURCE: Dynamic Chiropractic
By Richard C. Schafer, DC, FICC
The aim of this series is to define certain general principles that underlie almost all chiropractic adjustive technics. Parts I and II reviewed depth of drive, the articular snap, segmental distraction, timing the advantages of placing the patient’s spine in an oval posture, correct table height, and patient positioning objectives. Part III summarized the factor of time in the clinical approach and its underlying biomechanical principles of tissue viscoelasticity, fatigue, creep, and relaxation. Parts IV and V reviewed the need to visualize the loading effects on articular cartilage, joint lubrication, action of the intra-articular synovial tabs, the articular planes to deliver a corrective thrust most effectively. The fundamental types of contact, contact points and their options, securing the contact hand, and direction of drive were described. This column summarizes the rationale of adjustive velocity.
One’s preference in technic can be clinically justified as long as biophysical and physiologic principles are followed. In health care, however, we are not dealing with purely mechanical principles. We are dealing with patients, sensitive human beings, who are often already in pain, and we should not wish to induce any more discomfort during a correction than is necessary.
Thrust technics applied to an articulation can be divided into two categories: low-velocity technics (LVTs) and high-velocity technics (HVTs), and each has various subdivisions depending on the joint being treated, its structural-functional state, and the primary and secondary objectives to be obtained. The term adjustment velocity refers to the speed at which the adjustive force is delivered.
In either low-velocity or high-velocity technics:
The force applied may be low, medium, or high.
The duration of the force may be brisk or sustained.
The amplitude (distance of articular motion) may be short, medium, or long.
The direction of the force may be straight or curving and/or perpendicular, parallel, or oblique to the articular plane.
Overlying soft-tissue tension may be mild, medium, or strong.
Primary or secondary leverage may be applied early, synchronized, or late.
Contralateral stabilization may or may not be necessary.
Thrust onset may be slow, medium, or abrupt.