Spinal Manipulative Therapy on a Healthy Population: Protocol for a Randomized Blinding Feasibility Trial

Few manual chiropractic high velocity, low amplitude (HVLA) type shams have been validated in research. The proposed project is a randomized controlled trial (RCT) designed to assess a novel, full-spine, manual sham chiropractic maneuver and its blinding success.

This study aims to evaluate the blinding integrity of participants receiving a genuine or sham chiropractic maneuver. We will also be evaluating the effects of genuine chiropractic treatments relative to sham chiropractic treatments by measuring several neurophysiological mechanisms.

Participants (N=60) will be recruited from in and around Marietta, Georgia, United States. They will undergo a chiropractic physical exam and health history review with a licensed chiropractor and be randomized to either a sham or genuine chiropractic group (1:1 ratio). Participants, outcome assessors, and data analysts will be blinded to group allocation. The genuine group will receive diversified HVLA chiropractic spinal manipulative therapy (SMT), while the sham group will receive a novel chiropractic HVLA-emulating therapy. Each participant will attend 2 sessions spaced 1 week apart. Assessments will consist of blinding surveys postsessions (both visits) and presession (second visit). Additionally, we will measure gait parameters. The primary outcome of interest is blinding measured via the Bang Blinding Index (Bang BI). Secondary aims include measuring blinding via the James Blinding Index (James BI) and exploring the potential differential effects of genuine versus sham SMT on gait parameters.

This study is being supported and internally funded by the Dr. Sid E. Williams Center for Chiropractic Research at Life University in Marietta, Georgia, United States. Our study was prospectively registered on clinicaltrials.gov (NCT06931600) on March 28, 2025, and the first participant was enrolled on May 5, 2025. As of December 10, 2025, 18 participants have completed the trial. Projections for completing data collection, data analysis, and manuscript submission are Summer 2026, Fall 2026, and Winter 2027, respectively.

The significance of the current RCT will be in its ability to inform whether our novel, full-spine, manual sham SMT protocol successfully blinds participants, suggesting feasibility for future clinical trials, as well as assessing for secondary outcome measures between groups.