Chronic musculoskeletal pain is a common health condition that reduces quality of life and increases disability. Pain neuroscience education (PNE) has shown positive effects on pain perception, beliefs, and function, especially when combined with physical activity. This randomized controlled trial will compare the effectiveness of delivering PNE during aerobic exercise on a cycle ergometer versus aerobic exercise alone in patients with chronic musculoskeletal pain.

Participants will be randomly assigned to one of two groups:

PNE during aerobic exercise (experimental group),

Aerobic exercise alone (control group).

Both groups will perform supervised cycling sessions lasting 20-30 minutes at light intensity (Borg CR10 = 3, 40-50% HRmax). The experimental group will simultaneously receive interactive education about pain mechanisms, central sensitization, and self-management strategies, supported by visual aids and metaphors delivered by a therapist during cycling.

Outcomes will be measured at baseline and after the intervention, including:

Pain intensity (Visual Analog Scale),

Pressure pain threshold (algometry),

Functional performance (Sit-to-Stand test),

Safety and comfort (Likert scale),

The study will enroll 24 participants (12 per group). The findings are expected to clarify whether integrating education with exercise provides superior benefits compared to exercise alone, offering an innovative, safe, and cost-effective strategy for managing chronic musculoskeletal pain.

Objective To determine whether PNE delivered during cycling exercise produces greater improvements in pain intensity, pain thresholds, and functional outcomes than aerobic exercise alone.

Study Design This is a single-center, randomized controlled trial with two parallel arms (1:1 allocation). A total of 24 participants with chronic low back pain will be recruited from the Hospital Clínico de la Universidad de Chile. Randomization will assign 12 participants to the experimental group and 12 to the control group, using the Randomization software (www.randomization.com). The random sequence will be determined prior to the start of the initial assessments and will only be known to an external research assistant with no access to participant characteristics. The assignment will remain hidden and stored in the cloud until the end of the intervention and the collection of all study data. When a participant enrolls in the study, the external research assistant will inform the therapist of the assigned intervention group.

Intervention Experimental group (PNE + exercise): 20-30 minutes of supervised cycling at light intensity (Perceived exertion, Borg CR10 = 3) while receiving interactive PNE. Education covers neurobiology of pain, central sensitization, and self-management, supported by visual aids and metaphors.

Control group (exercise alone): 20-30 minutes of supervised cycling at the same intensity (Perceived exertion, Borg CR10 = 3), without educational content.

Sample Size and Analysis Based on prior effect sizes, 28 participants (14 per group) provide sufficient power to detect moderate differences. Data will be analyzed with mixed-model ANOVA (time × group) and additional parametric or nonparametric tests as appropriate. Statistical significance is set at p < 0.05.

Ethical Considerations The study is approved by the Ethics Committee of Hospital Clínico de la Universidad de Chile. Participants will provide informed consent before participation. Risks are minimal (fatigue or mild discomfort), while expected benefits include improved pain understanding, reduced pain intensity, and improved function. This study will be conducted in accordance with the Declaration of Helsinki.

Inclusion Criteria:

• Adults aged 18 to 65 years.
• Diagnosis of chronic low back pain lasting ≥ 12 weeks.
• Baseline pain intensity ≥ 4/10 on the Visual Analog Scale (VAS).
• Able to perform light to moderate aerobic exercise
• Willing and able to provide informed consent.

Exclusion Criteria:

• Inability to understand or follow instructions.
• Pregnancy.
• Active cancer diagnosis.
• Neurological disorders affecting the central nervous system (e.g., stroke).
• Participation in alternative or concurrent therapies for pain management.
• History of major orthopedic trauma or surgery in the last 12 months.
• Any medical contraindication to light exercise identified during the medical screening.

Outcome assessors will be blinded to group allocation. Participants and care providers cannot be blinded due to the nature of the intervention.