In the light of current knowledge, well-established factors of susceptibility to tendinopathy are the polymorphic variants of collagen, type I, alpha-1 (COL1A1) [33], collagen, type V, alpha-1 (COL5A1) [34] and matrix metalloproteinase 3 (MMP3) [35] genes. This evidence concerns the gene COL1A1 and disease of the tendon.