How a daily and moderate exercise improves ligament healing

Abstract Ligaments are strong bands of connective tissue which display high resistance to tension, allowing joint stability. However, sudden twisting motion and excessive stretching are causes of sprains. Medical managements involve initial symptomatic treatment and secondary rehabilitation regimen, without beneficial effect regarding the mechanical properties of the tissue. In fact, ligaments never recover their initial resistance to load tension. In this article, we reviewed the macroscopic and biochemical characteristics of normal and injured ligaments, with a special emphasis on the role of cytokines and growth factors during the healing process, and on the beneficial effect of a moderate exercise on the scar formation. Indeed, recent data highlighted: (1) the role of both IL-1 beta and bFGF during the inflammatory state to promote fibroblast and endothelial cell migration into the wound; (2) VEGF helped capillary growth during the proliferative state; (3) whereas TGF beta expression resulted in the deposition of a disorganised fibrotic extracellular matrix. In contrast, mechanical stimulation during a moderate exercise inhibited TGF beta expression, improving the deposition of specific collagen network and the overall ligament healing process.