Effects of exercise training on the matrix metalloprotease response to acute exercise

Matrix metalloproteases (MMPs) in the circulation are thought to modulate the activation of growth factors, cytokines, and angiogenesis, facilitating physiological adaptations to exercise training. The purpose of this work was to characterize serum MMP-1, MMP-2, MMP-3, and MMP-9 concentrations pre- and post-eight weeks of exercise training. We tested the hypothesis that exercise training would influence serum MMP concentrations in response to an acute resistance exercise test (ARET). Participants were randomized into an 8-week training program (5 days per week) that emphasized callisthenic (CT, N = 8) or resistance (RT, N = 8) exercise. Serum MMP concentrations (MMP-1, -2, -3, -9) were assessed in men (N = 16) in response to an acute bout of high-intensity resistance exercise (six sets of 10-RM squats with 2-min inter-set rest periods) both before and after 8 weeks of training. Training resulted in a temporal shift in the peak MMP-1 concentration from post-ARET to mid-ARET in both groups. Post-training, MMP-9 concentrations were increased immediately after the ARET in the CT group as compared to pre-training ARET concentrations. RT did not alter MMP-3 and -9 concentrations. These data suggest that the mode of exercise training influences the MMP response to an acute bout of exercise, revealing a possible role of MMPs in initiating training-specific adaptations.