Molecular Implications of Active and Passive Recovery Following High Volume Resistance Training

Abstract

PURPOSE: Deloading is widely practiced in the strength and conditioning community as a method to augment recovery; however, there is little molecular signaling data to fully explain the details of why this practice is beneficial. METHODS: Recreationally-trained, college-aged males (n = 30) underwent 6 weeks of volume based training, after which the participants were split into active recovery (AR) and passive recovery (PR) groups with delaod lasting 7 days. Participants donated a muscle biopsy from the vastus lateralis prior to week 1 (PRE), post training (POST), and post deload (DL). Protein expression for mTOR, AMPk, 4EBP1, and p70S6k was evaluated via western blotting. Additionally, blood was obtained via venipuncture, and serum levels of creatine kinase (CK), testosterone (TEST), and cortisol (CORT) were evaluated using commercially available assay kits. RESULTS: There was an effect of time for phosphorylated (p) 4EBP1 (p = 0.014) where PRE (p = 0.003) and POSTDL (p = 0.004) expression of p-4EBP1 were significantly higher than POST. CK activity also had an effect of time (p = 0.016) where CK at POST was significantly higher than at DL (p = 0.007). There was a significant group*time interaction of proteasome activity (p = 0.040) where post-hoc analysis revealed the AR group exhibited higher proteasome activity DL than the PR group (p = 0.051). Differences in protein expression for pan and phosphorylated mTOR, AMPk, p70S6K, and pan 4EBP1 were not significant (p > 0.05). Additionally, there were no significant differences in serum testosterone and cortisol levels (p > 0.05) CONCLUSION: AR may stimulate the PI3K/AkT pathway resulting in the phosphorylation of 4EBP1 potentially allowing hypertrophic adaptation to occur. Additionally, proteasome activity being upregulated with AR POSTDL may be beneficial in cleaving damaged protein structures. More research is needed to further investigate molecular signaling after deloading paradigms.