Where, When and When Not to Adjust

Today, with more and more studies concluding that the standard methods of chiropractic analysis are unreliable and not reproducible, many doctors of chiropractic are looking for a way to analyze the spine and extremities that can give them assurance.  Activator Methods Chiropractic Technique (AMCT) utilizes a protocol incorporating leg length analysis, pre- and post-adjustment, to determine exactly where, when and when NOT to adjust.  Therefore, this protocol not only helps to assure the doctor has found the affected spinal level but also enhances their confidence that the adjustment was successful.

Research has been conducted to evaluate interexaminer reliability using experienced chiropractors to measure reproducibility of prone leg length assessment and concludes that reliability of prone leg checks can be consistent.1 In comparison, static and motion palpation fall below what is clinically acceptable in terms of reliability.  AMCT utilizes prone extended leg length assessment (Position 1, Figure 1) to determine the functional short leg of the patient or pelvic deficient (PD) side, either the AS or PI ilium. Once the pelvic deficiency is corrected using precise contacts and lines of drive via the Activator adjusting instrument, the leg lengths become equal. (Figure 2).

ISOLATION TESTS: With the pelvis now balanced, screening for areas to adjust involves the use of active muscle tests called isolation tests. (Figure 3) Each isolation test corresponds to a specific vertebral segment.  The patient performs the requested motion and the doctor observes for any changes in leg length on the side that was originally the PD side.  If a change occurs, the doctor flexes the knees to 90 degrees (Position 2) and observes any change in the PD leg to determine which side of the spine to adjust.  If the PD leg lengthens in Position 2, the doctor adjusts the PD side of the corresponding segment on a specific contact (example, the mammillary or transverse process) with a precise line of drive utilizing the Activator adjusting instrument.  Correction will be observed in a post-adjustment leg check as the legs balance again.  If the patient’s leg lengths remain equal after the isolation test, no adjustment is required and the doctor moves on to test the next level of the spine.

AMCT conceives that the leg reactivity observed after an isolation test is due to facilitation as a result of nerve interference at the affected spinal level.  According to Malik Slosberg, DC, “normal muscles respond to normal, innocuous movements by appropriately contracting briefly to perform the requested movement and then relaxing.”

Therefore, in unaffected areas, these movements do not appear to alter relative leg lengths.  He goes on to say, “When a muscle group is facilitated, its response to stretch or contraction may be both excessive and prolonged.  Such alterations of muscle response apparently affect the functional leg length and result in alteration of relative leg lengths.”2

If facilitation is present, an exaggerated contraction of paraspinal muscles occurs and leg reactivity is observed.  Decades of documented clinical observation from doctors of chiropractic internationally have culminated into this protocol for analysis.   In one reliability study, 72 subjects were examined by two DC’s, for upper cervical subluxation, using a chin tuck isolation test.  Good reliability between examiners was found.3

Drs. Warren Lee and Arlan Fuhr founded instrument adjusting over 35 years ago.  Not only does an instrument allow the doctor to passively adjust the patient, but it also provides a specific contact, force, speed and line of drive so that you can be assured to affect the joint as efficiently as possible. The latest Activator adjusting instrument, Activator IV (Figure 4), has a reproducible preload and four precision force settings that have been studied in independent labora-tories.The minimal force setting starts at approximately 19 lbs and the instrument ranges up to a maximal force setting of approximately 55 lbs. Today, the Activator is still the fastest adjusting instrument. It is over 300 times faster than a manual thrust.4

At this speed, the doctor is affecting the involved joint before the muscle spindle reflex is initiated.  To compare the effects of manual adjusting to instrument adjusting, we can look at a bone movement study where a manual lumbar side-posture adjustment using 540N of force moved L4 1.1 mm.5  In a similar study, the Activator adjusting instrument moved L4 1.6 mm with a force of 140N.6

STUDY IN CLINICAL SETTING:  The following is a case series that will help illustrate the effectiveness of the AMCT protocol and adjustments in a clinical setting.  The purpose of this paper was to determine if there was a basis for the treatment of Temporomandibular disease (TMD) using the chiropractic protocol developed by Activator Methods, Inc.  The study was set in a private, solo practice of an Activator advanced proficiency rated chiropractor with 15 years experience.  Nine adult volunteers with articular TMD were recruited from the practice of the treating clinician.  Change was measured from baseline to follow-up using a Visual Analog Scale (VAS) for temporomandibular joint (TMJ) pain and maximum active mouth opening without pain. AMCT protocol for full spine and TMJ analysis and adjusting (Figure 5) was followed. Participants were typically seen three times per week for two weeks and, according to individual progress, thereafter for six more weeks. The results showed a median VAS decrease of 45 mm (range 21-71) and all experienced improvement. The median increase of mouth opening was 9 mm (range 1-15) with improvement in all.  The results of this prospective case series indicate that the TMD symptoms of these participants improved following a course of treatment using the AMCT protocol.7

AMCT is now taught in almost every chiropractic college in the United States.  With over 140 peer-reviewed articles and conference presentations published, doctors of chiropractic can be assured that, by choosing AMCT as their primary method of analysis and adjustment, they are offering their patients an effective and safe treatment and will have fewer doubts about where, when and when NOT to adjust!

For more information, contact Activator Methods, International, 2950 N. Seventh St. Suite 200, Phoenix, AZ 85014; or call (602) 224-0220.  www.activator.com


1. Nguyen, et al., JMPT 1999; 22(9):565-9.
2. Malik Slosberg DC, MS, in Today’s Chiropractic 17:17,1998. 
3. Youngquist, et al., JMPT 1989; 12:93-97.
4. Keller, et al., JMPT 1999; 22(2):75-86.
5. Maigne, Guillon, JMPT 2000; 23:531-536.
6. Nathan, et al., JMPT 1994; 17(7):431-44.
7. DeVocht, et al., JMPT 2003; 26(7): 421-425.

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