Assessment of chiropractic care on strength, balance, and endurance in active-duty U.S. military personnel with low back pain: a protocol for a randomized controlled trial

Abstract

Background: Low back pain (LBP) is a common cause of disability among U.S. military personnel. Approximately 20% of all diagnoses resulting in disability discharges are linked to back-related conditions. Because LBP can negatively influence trunk muscle strength, balance, and endurance, the military readiness of active-duty military personnel with LBP is potentially compromised. Chiropractic care may facilitate the strengthening of trunk muscles, the alteration of sensory and motor signaling, and a reduction in pain sensitivity, which may contribute to improving strength, balance, and endurance for individuals with LBP. This trial will assess the effects of chiropractic care on strength, balance, and endurance for active-duty military personnel with LBP.

Methods/design: This randomized controlled trial will allocate 110 active-duty military service members aged 18-40 with non-surgical acute, subacute, or chronic LBP with pain severity of ≥2/10 within the past 24 h. All study procedures are conducted at a single military treatment facility within the continental United States. Participants are recruited through recruitment materials approved by the institutional review board, such as posters and flyers, as well as through provider referrals. Group assignment occurs through computer-generated random allocation to either the study intervention (chiropractic care) or the control group (waiting list) for a 4-week period. Chiropractic care consists primarily of spinal manipulation at a frequency and duration determined by a chiropractic practitioner. Strength, balance, and endurance outcomes are obtained at baseline and after 4 weeks. The primary outcome is a change between baseline and 4 weeks of peak isometric strength, which is measured by pulling on a bimanual handle in a semi-squat position. Secondary outcomes include balance time during a single-leg standing test and trunk muscle endurance with the Biering-Sorensen test. Patient-reported outcomes include pain severity, disability measured with the Roland Morris Disability Questionnaire, symptom bothersomeness, PROMIS-29, Fear Avoidance Beliefs Questionnaire, expectations of care, physical activity, and global improvement.

Discussion: This trial may help inform further research on biological mechanisms related to manual therapies employed by chiropractic practitioners.

Trial registration: ClinicalTrials.gov, NCT02670148 Registered on 1 February 2016.

Keywords: balance; chiropractic; endurance; low back pain; military; spinal manipulative therapy; strength.

Conflict of interest statement

Ethics approval and consent to participate

Ethics approval for this trial was granted by Palmer College of Chiropractic (2015G171), the RAND Corporation (2013–0159), and NHP (NHPC.2015.0003, IRB of record: Naval Medical Center Portsmouth, VA). The trial protocol was also approved by the Naval Medical Center Portsmouth Clinical Investigation Department and the U.S. Army Medical Research and Material Command Human Research Protection Office.

Competing interests

The authors declare that they have no competing interests.

Publisher’s Note

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Figures

Fig. 1

Study flowchart

Fig. 2

Schedule of events

Fig. 3

Strength test. Isometric pulling in a semi-squat position with upright torso and eyes facing forward. Foot position is standardized within participants using platform markings (a). The bimanual handle (b) is attached to a force transducer. Pulling height is standardized using an adjustable post accommodating variable participant height (c)

Fig. 4

Balance test. Test performed with eyes open and with eyes closed. Pressure sensitive pads (a) are connected to a computer timer. Lifting the heel (b) removes the pressure, which starts the timer. Touching any pad with either foot stops the timer and ends the test

Fig. 5

Endurance (Biering-Sorensen) test. a Head, shoulders, and trunk extend over the edge of a table. The lower extremities are strapped to the table. b Timing begins when the participant lifts their arms off the support stool while maintaining a neutral trunk position. The test ends if pain or discomfort is experienced or after a maximum of 180 s.