Chiropractic mechanical force, manually assisted short lever adjusting is a spinoff of the specific toggle recoil adjusting techniques, which were based on the original chiropractic subluxation theory propounded by Daniel David Palmer in 1895. This article reviews: a) the principles of the chiropractic subluxation complex from the standpoint of its historical origin and present-day scientific status; b) the purpose and objectives of specific spinal manipulative techniques; c) the use of mechanical adjusting instruments to effect a velocity/direction controlled adjustive thrust; and d) an assessment of scientific and clinical data relating to the biomechanical and neurological aspects of mechanical force, manually assisted short lever adjusting.


Prime sources were from the National Library of Medicine’s on-line Index Medicus database, the Chirolars Research Resource Retrieval database, the Chiropractic Research Abstract Collection and the Chiropractic Library Consortium’s reference works. Direct search of other nonindexed chiropractic sources was limited to those available in the collection of the National Institute of Chiropractic Research. Early information never documented by publication was obtained by written personal communication.


The principal author selected articles reporting data (as opposed to anecdotal reports) from conference proceedings and peer-reviewed journals.


Data quality was assessed based on experimental conditions such as sample size, study design and statistical analysis.


While mechanical force, manually assisted short lever adjusting seemingly is capable of beneficially altering the cause/effect relationship of spinal subluxations, more research in the nature of controlled clinical trials is needed to ascertain its benefits in the chiropractic treatment of specific conditions.


Basic research is needed in order to establish the scientific basis for the chiropractic subluxation syndrome regardless of the technique employed.

J Manipulative Physiol Ther. 1992 Jun;15(5):309-17. [PMID:1302464]

Author information: Osterbauer PJ, Fuhr AW, Hildebrandt RW. Activator Methods, Inc. Phoenix, AZ.