In the current pilot study, we test how research clinicians can treat patients under study measurement conditions and with equipment resulting in modified treatment procedures. This pilot study will also test spinal stiffness using 3 different methods on 2 study visits. We will also assess the function of low back muscles during standing and while bending forward on 2 visits. These measurements include placing sensors on the back with tape and measuring the electrical activity of low back muscles. Participants with low back pain are treated with side-lying high-velocity low-amplitude spinal manipulation by experienced research clinicians who are doctors of chiropractic. Specifically, we will recruit 6 participants who are 21 - 64 years old and have had low back pain for at least 3 months. Each participant will attend 1 baseline visit, 1 enrollment visit, and 4 treatment visits over a period of approximately 4 weeks. Following the baseline visit, participant eligibility will be determined. The enrollment visit will be scheduled on the same day as the first treatment visit. The following feasibility data will be collected: