Objective: The purpose of this study was to generate data for conduction of a power analysis to investigate short-term effects of visceral manipulation associated with conventional physical therapy on pain intensity, lumbar mobility, and functionality of people with chronic low back pain and visceral dysfunctions.

Methods: This was a double-blinded, randomized, controlled, clinical trial preliminary study. A blinded evaluation was conducted involving 20 people with chronic low back pain with visceral dysfunction. Pain perception, lumbar mobility, and functionality were assessed in 3 moments: evaluation 1 (1 week before the intervention), evaluation 2 (immediately after the last intervention), and evaluation 3 (1 week after the last intervention). The protocol consisted of 50-minute session of conventional physical therapy and visceral manipulation. The participants were randomly allocated to 2 groups: 10 for the experimental group (conventional physical therapy and visceral manipulation) and 10 for the control group (conventional physical therapy and placebo visceral manipulation).

Results: Significant reductions were found in the experimental group for lumbar mobility and specific functionality in comparison with the control group (P < .05). There were no significant differences for pain perception and global functionality.

Conclusion: The combination of visceral manipulation and conventional physical therapy program demonstrated significant between-groups differences over time for lumbar spine mobility and specific functionality. These gains occurred after 5 sessions, once a week, and were maintained 1 week after the end of the treatment. This study generated data for conduction of a power analysis to inform the design for future clinical research in this line of inquiry.