Implementing workplace strategies to manage symptoms in office workers with chronic nonspecific spinal pain (CNSP) may improve both health- and work-related outcomes, as adherence to these interventions is more feasible in this context. Exercise therapy is considered the first-line treatment for CNSP; however, the added value of combining exercise therapy with manual therapy remains inconclusive. This study aims to examine the effects of short sessions of exercise therapy plus manual therapy, compared with exercise therapy plus sham manual therapy, delivered in the workplace, on health- and work-related outcomes in office workers with CNSP.

Objectives: To evaluate the effects of short sessions of exercise therapy plus manual therapy compared with exercise therapy plus sham manual therapy at work on self-perceived productivity, disability, global impression of change, pain intensity, depression, anxiety, and muscle tone.

Methods: A randomized controlled trial will be conducted. The study protocol was approved by the Research Ethics Committee of Catholic University of Murcia (UCAM) (CE042403). Eligible participants will be office workers from the UCAM University with nonspecific spinal pain. Participants will be randomized into two groups. The experimental group will receive exercise therapy plus manual therapy, while the control group will receive exercise therapy plus sham manual therapy. Both groups will complete two 15-minute sessions of exercise therapy per week for 8 weeks. In addition, the experimental group will receive two 15-minute sessions of manual therapy per week, while the control group will receive sham manual therapy during the same period.

Outcomes: The primary outcomes will be self-perceived productivity, disability, patient global impression of change, and pain intensity. Secondary outcomes will include depression, anxiety, and muscle tone. Assessments will be conducted at baseline, post-intervention, and at 3- and 6-month follow-ups. Any possible adverse events will be registered during the 8-weeks of interventions.

Sample Size Estimation: Sample size was calculated using G*Power 3.1. To detect differences between groups over time, a small effect size (f = 0.17) was assumed, with 80% power and a 5% alpha level, indicating a minimum of 50 participants. Allowing for a 20% dropout rate, the target sample size was set at 60 participants (30 per group).

Statistical Analysis: A repeated-measures ANOVA (time × group) will be used. Mauchly's test will assess sphericity; if violated, the Greenhouse-Geisser correction will be applied. Post-hoc pairwise comparisons will be adjusted using Bonferroni correction. Effect sizes will be reported as partial eta-squared, and Cohen's d will be used for post-hoc comparisons. A chi-square test will assess the effectiveness of blinding by evaluating participants' perceptions of the intervention.

Inclusion Criteria:

• Administrative professionals engaged in sedentary desk-based work utilizing visual display terminals (VDTs) for data processing and information management from the UCAM University
• Chronic nonspecific spinal pain defined as pain (≥4/10 on a numeric rating scale) persisting for at least the past 3 months and/or present on ≥50% of days during the previous 6 months
• The anatomical region of pain is defined from the occipital area to the gluteal folds

Exclusion Criteria:

• Participants with diagnosed conditions causing back pain, such as ankylosing spondylitis, infections, or other specific causes, including vertebral fractures
• Participants currently receiving any rehabilitative or pharmacological treatment for back pain during the 3 weeks prior to study enrollment
• Participants diagnosed with medical conditions that would prevent them from safely performing therapeutic exercise without medical supervision
• Participants who answer "Yes" to one or more questions on the Physical Activity Readiness Questionnaire for Everyone (PAR-Q+), indicating potential contraindications to physical activity, unless cleared by a healthcare provider

Participants will be blinded. Both groups will receive the same exercise sessions, delivered in small groups of up to 8 individuals that include participants from both study arms. In addition, both groups will receive a manual intervention, consisting of either manual therapy or sham manual therapy. The success of blinding will be evaluated after the intervention period by asking participants whether they believe they received the experimental intervention and how confident they are in their response (0-10 numerical rating scale).

Because most outcomes are self-reported, effective participant blinding will also ensure blinding of outcome assessment. For muscle tone assessment, independent assessors not involved in the study will perform the measurements. Data analysts will be blinded to group allocation. Only the therapists delivering the manual therapy interventions will be aware of group assignment.