Scheduled Intermittent Compression-Decompression Therapy Attenuates Cumulative Lumbar Shear Amplification During Prolonged Occupational Sitting

Background: Professional pilots and long-haul truck drivers represent populations at extreme risk for chronic low back pain (LBP) due to prolonged static sitting, whole-body vibration, and cumulative mechanical exposure. Traditional ergonomics focuses on posture, but does not address the progressive mechanical "creep" and shear amplification occurring at the L5/S1 segment. Objective: To evaluate a novel intervention—Scheduled Intermittent Compression-Decompression (SICD) therapy—in reducing the rate of L5/S1 shear amplification during a standardized 30-day occupational cycle. Methods: A randomized crossover trial with 20 professional participants. Biomechanical load was normalized (N/kg body mass). Primary outcomes included estimated L5/S1 shear forces, multifidus muscle thickness via ultrasound, and autonomic markers (HRV RMSSD). Results: SICD therapy reduced Day 30 shear amplification by 10.4% compared to controls (2.24 vs 2.50 N/kg, p < 0.05). Multifidus atrophy was significantly mitigated in the intervention group. Conclusion: SICD acts as a "mechanical reset," preventing the accumulation of shear forces beyond structural thresholds, providing a citable framework for industrial health interventions.