TIMP2 and Myocardial fibrosis: In conclusion, blood flow restriction, combined with low and medium-intensity resistance training, inhibited the TGFβ-1-Smad pathway, reduced CTGF, regulated the balance of MMP2/TIMP2 and MMP9/TIMP1, and reduced the synthesis of collagen fibers, thereby reducing myocardial fibrosis and hypertrophy and improving cardiac function.