SP2 Biomechanical Mechanisms in Chronic Low Back Pain –Identification of Compensatory Patterns and Clusters of Increased Spinal Loads

• Applicants: Privatdozent Dr. Luis Becker; Professor Dr. Hendrik Schmidt
• Subject Area: Orthopaedics, Traumatology, Reconstructive Surgery
• Term: since 2021
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 439742772

In the first funding period of FOR 5177, SP2 established the biomechanical foundations of chronic low back pain (cLBP), with a focus on the loading dynamics of the lumbar spine. Individual anatomical characteristics, clinical parameters, and demographic factors were systematically related to dynamic movement patterns. Clear sex- and age-specific differences emerged: men exhibited higher compressive and shear forces, while women generated greater lumbar loads through increased activation of the oblique abdominal muscles during asymmetric lifting tasks. Older participants showed restricted lumbar mobility and a reduced flexion-relaxation phenomenon, indicative of age-related neuromuscular alterations. High pain intensity correlated with inefficient muscle coordination and increased spinal loading; reduced muscle quality led to compensatory muscular overactivation. Additionally, a functional shift of load to adjacent segments, particularly the thoracic spine was observed, pointing to potential secondary overload effects. In the second funding period, SP2 investigates the interplay between compensatory movement patterns, neuromuscular coordination deficits, and inflammation processes to uncover their contribution to the chronification of back pain. Based on advanced movement analyses using 3D motion capture and surface EMG, compensatory patterns in the spine, pelvis, and lower extremities will be precisely quantified under both daily-life and maximum loading conditions. In parallel MRI-sequences will be able to link inflammatory processes with biomechanical adaptations. Longitudinal data from repeated measurements over a three-month period will allow for modeling of causal relationships between movement adaptations, inflammatory activity, and pain progression. Building on this, subject-specific musculoskeletal simulations will be conducted to identify key mechanical loading parameters and relate them to neuromuscular and soft-tissue adaptations. We hypothesize that interactions between mechanical loading, muscle activation, and inflammatory responses modulate pain processing in cLBP. These investigations provide essential groundwork for more precise diagnostics that, in addition to clinical and imaging parameters (SP1) and psychosocial factors (SP5), focus on the systematic quantification of compensatory movement patterns, neuromuscular coordination, and local inflammatory tissue response. Combined with data from other subprojects, these additional indicators may form the basis for evidence-based subtyping of cLBP, facilitate the differentiation of clinical phenotypes, and support the development of specific diagnostic criteria.

• DFG Programme: Research Units
• Subproject of: FOR 5177: The Dynamics of the Spine: Mechanics, Morphology and Motion towards a comprehensive Diagnosis of Low Back Pain
• International Connection: Iran
• Co-Investigator: Professor Adamantios Arampatzis, Ph.D.
• Cooperation Partner: Professor Dr.-Ing. Navid Arjmand