Static Stretching as a Multilevel Mechanobiological Process: An Integrative Framework from Mechanical Loading to Biological Adaptation

Static stretching is one of the most widely prescribed interventions in sports medicine, rehabilitation, and exercise science for improving joint range of motion (ROM) and flexibility. Despite decades of research, however, the biological mechanisms underlying its effects remain incompletely understood. Traditional explanations have primarily focused on muscle extensibility and passive tissue stiffness, whereas emerging evidence suggests that stretching induces coordinated adaptations across multiple mechanically interconnected biological systems. This integrative narrative review aimed to synthesize current evidence on the biological mechanisms underlying static stretching and to propose a conceptual framework explaining how externally applied mechanical loading is translated into coordinated biological adaptation. Current evidence from biomechanics, fascial biology, mechanotransduction, connective tissue biology, vascular physiology, and neuroscience was critically integrated to develop a unified mechanobiological framework describing the biological responses to static stretching. The available evidence indicates that static stretching should no longer be interpreted solely as a muscle-centered flexibility intervention. Instead, externally applied mechanical loading is transmitted throughout the myofascial continuum, where it is detected by mechanosensitive cellular structures and converted into biochemical signals through mechanotransduction. These signaling pathways regulate extracellular matrix remodeling, vascular adaptation, inflammatory modulation, and neural regulation, thereby generating coordinated biological adaptations. This framework provides a biologically plausible explanation for the heterogeneous findings reported in the stretching literature and the substantial inter-individual variability observed following identical stretching interventions. The proposed mechanobiological framework redefines static stretching as a biologically active mechanical stimulus coordinating adaptive responses across multiple levels of biological organization. By integrating evidence from previously independent biological systems, this conceptual model advances the current understanding of static stretching and provides a theoretical foundation for future mechanobiological research in sports medicine, rehabilitation, and exercise science.