Eight Weeks of Resistance Training Reduces IL-15 Response to Acute Resistance Exercise in Trained Men

Abstract

PURPOSE: Compare the effects of 8-weeks of high intensity (HVY) or high volume (VOL) resistance training on the plasma cytokine response. METHODS: Twenty resistance trained men were randomly assigned to either a HVY (22.6±2.3 y; 87.0±15.1 kg; 1.79±0.05m) or VOL (24.5±2.6 y; 89.5±12.9 kg; 1.66±0.34m) protocol. Prior to the 8-week resistance training program, participants performed an acute bout of exercise using either the HVY (3-5 reps; 90% 1-RM) or VOL (10-12 reps; 70% 1-RM) training protocol (PR-T). The acute exercise protocol was repeated following the 8-week training program (PO-T). Blood samples were obtained prior to (PR), immediately (IP), 30 min (30P) and 60 min (60P) post-exercise at PR-T and PO-T. Samples were analyzed for IL-15, IL-6, and Fractlkine (CX3CL1) at each time point. Data were analyzed using a group x training x time repeated measures ANOVA. Bivariate relationships were examined by Pearson product-moment correlations. Additionally, area under curve (AUC) was assessed with a group x training repeated measures ANOVA. RESULTS: A significant training x time interaction was observed for IL-15 (p =0.011), as well as a main effect for time (p = 0.001). Post Hoc analysis indicated that IL-15 concentrations were lower (p = 0.023) at 60P PO-T (4.76 ± 4.34 pg·ml-1) compared to 60P (6.83 ± 5.73 pg·ml-1) at PR-T. Additionally, IL-15 concentrations were elevated (p = 0.009) from PR (6.96 ± 5.52 pg·ml-1) at IP (8.08 ± 5.88 pg·ml-1), and reduced (p=0.032) at 60P (5.66 ± 5.12 pg·ml-1). A significant main effect for time was observed for IL-6 (p = 0.001). Pairwise comparisons indicated that IL-6 concentrations increased from PR (9.74 ± 8.27 pg·ml-1) to IP (13.21 ± 8.91 pg·ml-1; p < 0.001), 30P (13.45 ± 9.30 pg·ml-1; p < 0.001) and 60P (13.26 ± 9.84 pg·ml-1; p = 0.001). No significant interactions were noted for CX3CL1 concentration, nor were any AUC interactions noted for IL-15, IL-6 or CX3CL1. Significant correlations were observed between maximal squat and bench press strength and CX3CL1 AUC at PR-T (r=-0.516, p=0.020; r=-0.630, p=0.003; respectively) and PO-T (r=-0.556, p=0.011; r=-0.680, p=0.001; respectively). CONCLUSIONS: Short-term resistance training programs appeared to reduce post-exercise IL-15 concentrations. In addition, strength appeared to have an inverse relationship with CX3CL1 concentrations.