Effect of chiropractic manipulative therapy on reaction time in special operations forces military personnel: a randomized controlled trial

Abstract

Background: Chiropractic manipulative therapy (CMT) has been shown to improve reaction time in some clinical studies. Slight changes in reaction time can be critical for military personnel, such as special operation forces (SOF). This trial was conducted to test whether CMT could lead to improved reaction and response time in combat-ready SOF-qualified personnel reporting little or no pain.

Methods: This prospective, randomized controlled trial was conducted at Blanchfield Army Community Hospital, Fort Campbell, KY, USA. Active-duty US military participants over the age of 19 years carrying an SOF designation were eligible. Participants were randomly allocated to CMT or wait-list control. One group received four CMT treatments while the other received no treatment within the 2-week trial period. Assessment included simple hand/foot reaction time, choice reaction time, and Fitts' Law and whole-body response time. On visits 1 and 5, the same five assessments were conducted immediately pre- and post-treatment for the CMT group and before and after a 10-min wait period for the wait-list group. Primary outcomes included between-group differences for the pre-CMT/wait-list period at visit 1 and visit 5 for each test. Secondary outcomes included between-group differences in immediate pre- and post-(within visit) changes. Analysis of covariance was used for all data analysis.

Results: One hundred and seventy-five SOF-qualified personnel were screened for eligibility; 120 participants were enrolled, with 60 randomly allocated to each group. Due to technical problems resulting in inconsistent data collection, data from 77 participants were analyzed for simple hand/foot reaction time. The mean ± standard deviation (SD) age was 33.0 ± 5.6 years and all participants were male. No between-group statistically significant differences were found for any of the five biomechanical tests, except immediate pre- and post-changes in favor of the CMT group in whole-body response time at both assessment visits. There were four adverse events, none related to trial participation.

Conclusions: A single session of CMT was shown to have an immediate effect of reducing the time required for asymptomatic SOF qualified personnel to complete a complex whole-body motor response task. However, sustained reduction in reaction or response time from five tests compared with a wait-list control group was not observed following three sessions of CMT.

Trial registration: ClinicalTrials.gov, NCT02168153 . Registered on 12 June 2014.

Keywords: Chiropractic; Military; Reaction time; Response time; Special Operations Forces; Spinal manipulative therapy.

Conflict of interest statement

Ethics approval and consent to participate

Ethics approvals for the trial protocol were received from three Institutional Review Boards (IRBs): Palmer College of Chiropractic (#2012G143), the RAND Corporation (#2012–03520 AM02), and the Dwight D. Eisenhower Army Medical Center (#389611), which is the IRB of record for Blanchfield Army Community Hospital. An additional approval was given by the US Army Medical Research and Material Command, the Human Research Protection Office, and the Clinical Investigation Regulatory Office. All changes to the protocol were submitted to and approved by all three IRBs. All trial investigators have completed training in the protection of human subjects as required by the respective collaborating institutions. A Cooperative Research and Development Agreement was established between the Clinical Investigation Regulatory Office and the Samueli Institute prior to trial commencement. The Cooperative Research and Development Agreement was approved for the period of April 2014 through April 2017. All aspects of the trial were thoroughly explained to all potential participants and all participants in the trial provided written informed consent.

Consent for publication

Not applicable.

Competing interests

The authors declare that they have no competing interests.

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Figures

Fig. 1

Depiction of computer image used for the Fitts’ law test. The curser is moved using a computer mouse from one circle to the other and clicked by a participant. The curser is then moved back to the original circle and clicked again, finishing the sequence. Thirty-two sequences using pairs of differently oriented and sized circles were used

Fig. 2

Image of the t-wall®. Participants manually strike the lit panel, causing another panel to light in random sequence. Participants completed this test as quickly as possible by striking a random sequence of 100 lit panels

Fig. 3

Trial flow diagram. CMT chiropractic manipulative therapy