The long-term goal for this study is to understand the physiological mechanisms of various forms of spinal manipulation in order to refine and improve this therapy for appropriately selected patients. The objective of this study is to assess the effects of high-velocity low-amplitude spinal manipulation and low-velocity variable amplitude spinal manipulation on three types of sensorimotor abilities in patients with low back pain.

In collaboration with the University of Iowa, the Palmer Center for Chiropractic Research will pursue the following specific aim: To determine the effects of 2 weeks (4 applications @ 2 per week) of HVLA-SM and LVVA-SM to the lumbo-pelvic region, compared to a control group receiving light effleurage and a sham mechanically assisted adjustment, on sensorimotor function as measured by: lumbo-pelvic repositioning ability, standing postural sway and response to sudden trunk loading;

Inclusion Criteria:

• 21 to 65 years old
• Low back pain (LBP) score an 11 point numerical rating scale: (must be > 4 at the Phone Screening OR Baseline 1 Visit) AND (must be > 2 at the Phone Screen, Baseline 1 AND Baseline 2 Visits)
• Acute (less than 7 days), sub-acute (7 days to 7 weeks), or chronic (more than 7 weeks) LBP matching classifications 1, 2, or 3 of the Quebec Task Force (QTF) Classification system - QTF 1: Pain without radiation, QTF 2: Pain + radiation to proximal extremity, QTF 3: Pain + radiation to distal extremity, QTF 7: Spinal stenosis
• Written informed consent (ICD1, ICD2 and ICD3)

Exclusion Criteria:

• Ongoing treatment for low back pain by other health care providers - unwillingness to postpone use of all other types of manual treatment for LBP except those provided in the study (including chiropractic and osteopathic SM, physical therapy and massage) for the duration of the study period.
• Co-morbidities Bleeding Disorders Bone and Joint Pathology Cauda Equina Syndrome Contra-indication to spinal manipulation, in general Current or Pending Litigation General Poor Health Inflammatory or Destructive tissue changes to the spine Neuromuscular Diseases Obesity Osteoporosis Peripheral Neuropathies Spinal Surgery Suspicion of drug or alcohol abuse Uncontrolled hypertension Vascular claudication
• Quebec Task Force (QTF) on Spinal Disorders QTF 4: Pain + radiation to upper/lower limb with neurologic signs QTF 5: Presumptive compression of a spinal nerve root on a simple roentgenogram QTF 6: Compression of a spinal nerve root confirmed by specific imaging techniques QTF 8: Postsurgical status, 1-6 months after intervention QTF 9: Postsurgical status, >6 months after intervention 9.1: Asymptomatic 9.2: Symptomatic QTF 10: Chronic pain syndrome QTF 11: Other diagnoses
• Pregnant or nursing women
• Pacemaker
• Inability to read or verbally comprehend English
• Any Joint Replacement
• Use of spinal manipulation within the past 4 weeks. If participants are willing to delay study enrollment until four weeks post spinal manipulative therapy, then we will schedule accordingly until this criterion is met
• Sensitivity to tape used during the biomechanical assessments
• If the Study Clinician believes that diagnostic procedures other than x-rays or dipstick urinalysis are necessary to diagnose a participant's condition, then the participant will be excluded
• Beck Depression Inventory-II greater than or equal to 29
• Retention of legal advice and an open or pending case for a health-related condition

Once the resulting manuscripts have been published, data sets will be provided for public access. Potential investigators can contact one of the Co-PIs to present their hypothesis, study design, instruments and/or data on which to focus, and resources required. Depending upon the needs and desires of the requesting party, the data that are shared may include analytic tables or de-identified or limited data sets that are transmitted to the requesting parties for additional analyses.

2 weeks

Any untoward medical occurrence that may present itself during the conduct of the study which may or may not have a causal relationship with the study procedures.

*The total number of AEs may exceed the total # of people affected because some people experienced multiple AEs.