(886.17) Global DNA Methylation Status in Relation to Resistance Training with High vs Low Loads to Failure

Poster Board Number: E326

Casey Sexton (Auburn University), Joshua Godwin (Auburn University), Bradley Ruple (Auburn University), Mason Mcintosh (Auburn University), Shelby Osburn (Auburn University), Blake Hollingsworth (Auburn University), Philip Agostinelli (Auburn University), Andreas Kavazis (Auburn University), Timothy Zeigenfuss (Center for Applied Health Sciences), Hector Lopez (Center for Applied Health Sciences), Ryan Smith (TruDiagnostic), Kaelin Young (Edward Via College of Osteopathic Medicine, Auburn University), Varun Dwaraka (TruDiagnostic), Christopher Mobley (Auburn University), Adam Sharples (Norwegian School of Sport Sciences), Michael Roberts (Auburn University, Edward Via College of Osteopathic Medicine)

Objective: Our objective was to determine how global DNA methylation status of skeletal muscle differs with resistance training (RT) to failure in trained participants using either 80% of their estimated one-repetition maximum (Est. 1-RM) (80FAIL) or 30% of their Est. 1-RM (30FAIL).

Hypotheses: We hypothesize there will be a significant decrease in global DNA methylation with both RT conditions, but that 30FAIL RT will elicit a greater magnitude of hypomethylation than 80FAIL RT.

Methods: Previously trained college-aged males (n = 11, age 23 ± 4 years, percent fat 11.4 ± 6.4%, training experience 4 ± 3 years, squat strength relative to body weight 1.7 ± 0.3) voluntarily underwent two bouts of RT. Participants completed both the 80FAIL and 30FAIL conditions (separated by one week). For each bout of RT, participants completed 4 sets of back squats and 4 sets leg extensions with either the 80FAIL or 30FAIL training conditions. Muscle biopsies were collected from the vastus lateralis before (PRE), 3 hours (3hPOST), and 6 hours (6hrPOST) after each RT bout. DNA was then batch-isolated from muscle tissue and submitted for analysis using the Illumina MethylationEPIC array.

Results: Total number of repetitions performed were significantly higher for 30FAIL training vs 80FAIL training (p lt; .001), however total training volume (sets x reps x load) was not significantly different between conditions (p= 0.571). Global methylation changes between PRE, 3hPOST, and 6hPOST are presented herein. In addition, significant differences between conditions are emphasized for each post-exercise time point.

Conclusions: With this study we expand our understanding of how the manipulation of RT variables affect epigenetic modifications in skeletal muscle.