This study evaluates the effectiveness of a specific manual therapy approach based on the Algo-K decision algorithm in patients with subacute low back pain radiating to the lower limb. Algo-K helps select the most suitable lumbar mobilization technique according to the patient's pain response. The experimental group will receive a five-minute targeted manual therapy in addition to standard physiotherapy, while the control group will receive a non-specific mobilization. The study aims to determine whether this algorithm-guided intervention leads to faster and greater improvement in pain and disability.

Subacute low back pain (LBP) with radiating symptoms is a common musculoskeletal disorder with a risk of chronicization. Manual therapy is often used in physiotherapy to treat LBP, but its effectiveness varies widely due to heterogeneous practices and lack of specificity. The Algo-K algorithm was developed to guide therapists in selecting the most appropriate mobilization technique based on patients' symptomatic responses during movement tests.

This multicenter randomized controlled trial compares the effectiveness of a specific manual therapy guided by the Algo-K algorithm versus a non-specific manual therapy added to a standardized exercise-based physiotherapy program. Sixty adult patients with subacute LBP and radiating pain will be included. Participants will be randomly assigned to either:

• Experimental group: 5 minutes of specific lumbar mobilizations based on the Algo-K decision tree;
• Control group: 5 minutes of non-specific mobilization at a distant thoracic level.

Both groups will receive the same standard physiotherapy care based on exercise and education, delivered over 12 sessions within a 60-day period.

The primary outcome is the Oswestry Disability Index (ODI) score at 26-30 days. Secondary outcomes include pain intensity (Numeric Rating Scale), pain distribution (body diagram), and long-term disability (ODI at 52-60 days). The hypothesis is that the specific, patient-tailored manual therapy will improve functional outcomes and reduce pain more effectively than non-specific mobilization.

Inclusion Criteria:

• Adults 18 65 y o
• Sub acute low back pain (7 days - 3 months) with irradiation to one lower limb, pain 3 10/10
• Mechanically responsive pain
• ODI > 20 % and < 80 %
• Prescription ≥ 12 physiotherapy sessions (or un specified)
• Able to complete 12 sessions in ≤ 60 days
• Affiliated to French social security
• Signed informed consent

Exclusion Criteria:

• Suspicion or history of serious pathology (cancer, systemic inflammatory disease, etc.)
• Main complaint other than low back pain with irradiation
• Prior spine or hip surgery (no time limit) / thoraco abdominal surgery < 3 y
• Central Sensitization Inventory ≥ 37
• HAD anxiety or depression sub score ≥ 8
• Planned lumbar infiltration during follow up
• Pregnancy or breastfeeding
• Legal protection (guardianship, custody, imprisonment)

Patients unaware of allocation ; sham mobilization in control arm