Multimodal Exercise Therapy for Non-Surgical Intervention of Nonspecific Low Back Pain.

Primary: to determine whether a 6-week supervised home-based multidimensional exercise program (aerobic, strength, balance, flexibility) added to short-term NSAIDs improves 12-month functional outcome (ODI) compared with NSAIDs alone.

Secondary: (1) compare pain intensity, quality of life, recurrence, and safety between arms; (2) develop and validate a radiomics-plus-machine-learning model that uses baseline MRI features of paraspinal muscles, demographic, clinical, and functional variables to predict treatment response and recurrence risk; (3) integrate the validated model with the exercise intervention to create a risk-stratified, early-intervention clinical pathway for chronic LBP.

Study Design：Multicenter, prospective, assessor-blinded, superiority RCT with 1:1 allocation, conducted at 4 tertiary hospitals and 1 academic research center in Beijing. Randomization (block sizes 4 and 6, stratified by center and sex) generated centrally via web-based system; allocation concealed from outcome assessors and statisticians.

Population Inclusion: age ≥ 60 y; LBP ≥ 3 months; ODI 20-60; MRI evidence of paraspinal muscle fatty infiltration ≥ Goutallier grade 2; no surgical indication; able to exercise.

Exclusion: specific spinal pathology (infection, tumor, fracture, severe deformity); previous lumbar surgery; severe comorbidities limiting exercise; cognitive impairment; current participation in another trial.

Interventions Experimental: 6-week multidimensional exercise (5 days/week, 30-40 min) plus 4-week oral NSAIDs (celecoxib or acetaminophen, dose-adjusted). Exercise comprises (1) low-intensity aerobic walking; (2) light-load high-repetition strength training (upper limb, lower limb, core); (3) balance and proprioceptive drills; (4) stretching. Printed manual + training diary; weekly phone/video supervision; compliance algorithm (≥ 75 % overall score required).

Control: same NSAID regimen alone. Both groups receive standardized education booklet on posture and activity pacing.

Outcomes Primary: ODI at 12 months (minimal clinically important difference 10 points). Secondary: VAS pain, JOA score at 1, 3, 6, 12 months; recurrence (≥ 24 h LBP with VAS > 2) within 12 months; patient satisfaction (NASS questionnaire); adverse events; compliance.

Imaging: axial MRI (3 T) at L1-5; semi-automated segmentation (3D-Slicer) to quantify cross-sectional area, fat fraction, radiomic features (shape, first-order, GLCM, GLRLM, GLSZM, GLDM).

Functional: Biering-Sørensen endurance test; surface electromyography of multifidus.

Biomarkers: baseline bloods (CBC, renal, hepatic panels). Sample Size 314 participants (157 per arm) provide 80 % power (α = 0.025 one-sided) to detect 15-point ODI difference (SD 15), allowing 10 % attrition.

Data Analysis

Intention-to-treat primary analysis: ANCOVA adjusted for baseline ODI, sex, center. Secondary longitudinal scores analyzed with mixed-effects models; recurrence with Kaplan-Meier and Cox regression.Radiomics:

7:3 split; 100× bootstrap; LASSO feature selection; multivariable modeling (logistic regression, random forest, XGBoost, LightGBM, MLP); performance reported as AUC, sensitivity, specificity, PPV, NPV, F1; SHAP/LIME for interpretability. Internal 5-fold cross-validation; final model deployed as web calculator.

Quality \& Ethics Protocol approved by central ethics committee; registered at Chictr.org.cn. Written informed consent. Data entry via validated EpiData system; double verification; 5-year retention. Adverse events monitored by independent DSMB. Study conducted in accordance with Helsinki Declaration and ICH-GCP.