Relative Androgen-responsive Gene Expression Changes In Response To High- Versus Low-load Resistance Training

Despite growing research connecting androgens (i.e. testosterone and dihydrotestosterone) and associated intramuscular signaling, no existing investigations delineate between high- versus low-load resistance training responses. PURPOSE: to examine the extent to which acute low-load (LL) versus high-load (HL) training affects specific androgen-responsive genes in young, healthy participants. METHODS: 10 resistance-trained males (23.2 ± 4.7 years) were recruited for this crossover study, whereby all participants assessed their strength by performing leg press and bench press one-repetition maximum (1RM) tests. They subsequently (one week later) completed two volume- and intensity-equated resistance training sessions (HL [80%1RM] and LL [50%1RM]) in sequence and separated by 7-10 days. Vastus lateralis skeletal muscle tissue biopsy samples were acquired with each experimental loading session at baseline (PRE), 3-hours (3POST3H), and 24-hours (POST24H) post-exercise to examine the relative expression of several androgen-responsive genes (AR, IGF1-Ea, MyoD, Myogenin, and p21-cip) via real time polymerase chain reaction amplification. Changes in these genes’ expression from baseline were assessed via separate two-way (load [HL, LL] x time [PRE, POST3H, POST24H]) analysis of variance (ANOVA) with repeated measures, whereby all analyses were performed at a p < 0.05 significance level. RESULTS: Analyses largely failed to reveal any significant main nor interaction effects for relative gene expression changes. However, significant main time effects were found for two genes, whereby AR expression was significantly lower at POST24H versus PRE (0.54 ± 0.42 fold change; p = 0.021) and MyoD expression was significantly elevated from PRE at POST3H (2.03 ± 1.64 fold change; p = 0.005). Otherwise, no main load nor load x time interaction effects were observed for relative AR or MyoD gene expression changes. CONCLUSION: Despite failing to determine any load-specific gene expression changes, these data support further investigations with larger samples and longitudinal designs to elucidate potential time-dependent androgen receptor- and myogenesis-facilitated post-training adaptations. Supported by: Texas Chapter Student Research Development Award and Health, Human Performance, and Recreation Graduate Student Research Grant