Numerous studies have demonstrated that several inflammation-related myokines, including interleukin-1 (IL-1), interleukin-8 (IL-8), interleukin-18 (IL-18), tumor necrosis factor-α (TNF-α), plasminogen activator inhibitor-1 (PAI-1), matrix metalloproteinase-3 (MMP-3), MMP-9, transforming growth factor-β (TGF-β), and C-reactive protein (CRP), may contribute to the development of sarcopenia [78–80]. Here, MMP9 is linked to sarcopenia.