3606 Board #53 June 3 9:30 AM - 11:00 AM Post-STEMI Age-related Non-classical Monocyte CCR2 Expression Differences In Response To Stress Hormones Anson Blanks, Charles S. Schwartz, Lauren N. Pedersen, Leo F. Buckley, Edmund O. Acevedo, FACSM, Antonio Abbate, R. Lee Franco. Virginia Commonwealth University, Richmond, VA. Email: firstname.lastname@example.org (No relationships reported) C-C chemokine receptor 2 (CCR2) plays an important inflammatory role following ST segment elevation myocardial infarction (STEMI) by regulating the chemotaxis of monocytes to damaged tissue. Circulating non-classical monocytes are responsible for debris clearance following STEMI and are positively correlated with age in healthy individuals, as well as increased plaque area in cardiovascular disease (CVD) patients. While post-STEMI non-classical composition within the monocyte population has been defined in CVD patients, age related differences in monocyte phenotypic characteristics and response to stress hormones remains unclear. Specifically, epinephrine (EPI) and cortisol (CORT), which are elevated during exercise, have been shown to both affect immune cell function and positively correlate to infarct size. PURPOSE: To determine the in-vitro effects of CORT and EPI on non-classical monocyte CCR2 expression in young and old patients post-STEMI. METHODS: Blood was collected from 19 volunteers 72 hours post-STEMI. Samples were grouped by age (<50 [YNG, n=7, 38.7�0 yrs] or ?50 [OLD, n=12, 61.7�9 yrs]). Blood was diluted to 1 x 106 cells/mL and cultured for 4 hours either unstimulated, stimulated with EPI (10-8 M), or CORT (10-6 M). Cultures were stained against CD14, CD16, and CCR2. Flow cytometry was performed and non-classical monocytes were determined based on CD14 and CD16 expression. RESULTS: Unstimulated CCR2 expression in non-classical monocytes was neither significantly different between groups (50.75�.91 [YNG] vs. 71.52�.79 [OLD], p=0.104), nor was there a significant correlation between age and CCR2 expression (r=0.44, p=0.059). However, there was a significant difference in non-classical monocyte CCR2 expression following EPI (47.69�22 [YNG] vs. 80.74 � 45.60 [OLD], p=0.03) and CORT (44.29�.27 [YNG] vs. 83.77�.53 [OLD], p=0.008). CONCLUSION: The results suggest an age-related difference in non-classical monocyte CCR2 expression after EPI and CORT stimulation. It is plausible that aged individuals have an increased sensitivity to EPI and CORT, which increases non-classical monocyte CCR2 expression. Post-STEMI exercise prescriptions may need to be modulated in older individuals to account for exercise induced hormonal responses. Supported by NIH Grant R34HL121402 3607 Board #54 June 3 9:30 AM - 11:00 AM Exercise Normalizes Dysfunctional Adipose Tissue Phenotype in FGF21-Null Mice Jay Porter1, Joe L. Rowles, III2, Justin A. Fletcher1, Terese M. Zidon1, Nathan C. Winn1, Leighton McCabe1, Young-Min Park1, James W. Perfield3, John P. Thyfault, FACSM1, R. Scott Rector1, Jaume Padilla1, Victoria J. Vieira-Potter1. 1University of Missouri, Columbia, MO. 2 University of Illinois at Urbana-Champaign, Urbana-Champaign, IL. 3Lilly Research Laboratories, Indianapolis, IN. (No relationships reported) Adipose tissue (AT) immunometabolic health predicts systemic metabolic health. Exercise improves metabolic function and insulin sensitivity and is thought to improve AT metabolism by reducing AT inflammation. Fibroblast growth factor 21 (FGF21) is a pleotropic hormone-like protein that has been shown to have beneficial effects by improving glucose and lipid metabolism and may have beneficial effects on AT immunometabolic function. However, it is unknown whether exercise-induced AT adaptations are mediated through FGF21. PURPOSE: To determine the role of FGF21 in exercise-induced adaptations in white (W) and brown (B) AT. METHODS: Male FGF21 knock-out (KO) and wild type (WT) mice were fed normal chow and either exercise trained via voluntary wheel running (EX) or kept sedentary (SED) for 8 weeks. Visceral (i.e., epididymal), subcutaneous (inguinal region) WAT, and BAT (interscapular region) depots were removed, weighed and flash-frozen in liquid nitrogen. Techniques used: EchoMRI - body composition, real-time PCR - gene expression, Western blotting - protein content, and H&E staining - histology. RESULTS: FGF21KO mice weighed more (p<0.05) and had greater overall adiposity. In addition to having greater systemic insulin resistance (IR) based on HOMA-IR (p<0.01), AT from FGF21KO mice was more insulin resistant (p<0.01) based on fasting plasma insulin and free fatty acids. EX decreased AT IR (p<0.01) but only tended to decrease HOMA-IR (p=0.112). Phospho-Akt and GLUT4 proteins were increased in AT of FGF21KO mice, combined with increased IR, is suggestive of dysregulated glucose uptake. In WAT and BAT, inflammatory and oxidative stress genes (e.g., MCP-1, TNF?, CD11c, P22phox) were significantly upregulated in FGF21KO and normalized by EX. Mitochondria content, indicated by COX III and IV protein, were significantly reduced in BAT of FGF21KO. CONCLUSION: Absence of FGF21 increases AT IR as well as WAT and BAT inflammation; EX rescues this phenotype. Normal WAT mitochondrial adaptations to EX may be adversely affected by loss of FGF21. Metabolic dysfunction in FGF21KO appears largely due to excess AT, and is almost completely normalized by EX. Supported by grant number R25GM056901 from the NIGMS of the NIH, VA-CDA2 IK2BX001299 (RSR), and MU Research Board, Corporate Advisory Board, and Research Council. 3608 Board #55 June 3 9:30 AM - 11:00 AM Resistance Exercise and Polyphenol Supplementation elicits Unique Recruitment of Monocyte Subsets in Untrained Men Adam Jajtner1, Jay Hoffman, FACSM2, Jeremy Townsend3, Kyle Beyer2, Alyssa Varanoske2, David Church2, Michael La Monica2, Josh Riffe2, Tyler Muddle2, Leonardo Oliveira2, Kelli Herrlinger4, Shlomit Radom-Aizik5, David Fukuda2, Jeffrey Stout2. 1Kent State University, Kent, OH. 2 University of Central Florida, Orlando, FL. 3Lipscomb University, Nashville, TN. 4Kemin Foods, L.C., Des Moines, IA. 5University of California Irvine, Irvine, CA. (Sponsor: Jay Hoffman, FACSM) (No relationships reported) PURPOSE: To examine the monocyte subset response to resistance exercise and supplementation with an aqueous proprietary polyphenol blend (PPB) sourced from Camellia sinensis. METHODS: Untrained men (n=38, 22.1 � 3.1 yrs; 174.0 � 7.9 cm; 77.8 � 14.5 kg) were randomized to: PPB (n=13), placebo (PL; n=15) or control (CON; n=10). PPB and PL supplemented for 28 days prior to an acute bout of resistance exercise, consisting of 10 repetitions at 70% of 1-RM for the squat (6 sets), leg press (4 sets) and leg extension (4 sets). Blood was drawn pre (PR), immediately (IP), 1 (1H), 5 (5H), 24 (24H) and 48 (48H) hours post exercise (PPB/PL), or rest (CON). Biopsies were obtained from the vastus lateralis at PR, 1H, 5H and 48H. Plasma and intramuscular monocyte chemoattractant protein-1 (MCP-1) was assessed by multiplex assay. Relative percent of classical (CLAS; CD14++/CD16-), intermediate (INT; CD14++/CD16+) and nonclassical (NC; CD14+/CD16+) monocytes were assessed via flow cytometry. Repeated measures ANOVA were applied, and non-normally distributed data were LN transformed. RESULTS: A group x time interaction was observed for circulating MCP-1 (p = 0.005), which was greater at 5H in PPB (502.0 � 154.2 pg?ml-1; p = 0.001) and PL (416.8 � 109.9 pg?ml-1; p = 0.012) than CON (307.3 � 142.6 pg?ml-1). A time effect was observed for intramuscular MCP-1 content (p < 0.001), with elevations observed (PR: 9.6 � 5.0 pg?mg-1; p < 0.001) at 1H (374.2 � 388.8 pg?ml-1), 5H (595.7 � 528.6 pg?ml-1) and 48H (217.0 � 189.1 pg?ml-1). Interactions were observed for CLAS, INT and NC (p < 0.001) populations. At IP, CLAS was reduced in PPB (86.2 � 7.6%; p = 0.008) and PL (85.9 � 5.1%; p = 0.003) versus CON (93.8 � 4.3%). At 1H, PPB (96.3 � 2.0%; p = 0.002) and PL (95.3 � 4.0%; p = 0.006) was greater than CON (90.8 � 4.3%). INT were greater at IP in PPB (4.9 � 2.3%; p = 0.034) and PL (6.0 � 2.0; p = 0.001) than CON (2.9 � 1.8%) and reduced at 1H in PPB (1.6 � 1.0%; p = 0.003) and PL (2.0 � 1.2%; p = 0.008) versus CON (3.4 � 1.6%). PPB was greater than CON at 24H (6.7 � 2.9%; 4.0 � 0.9%; p = 0.016) and 48H (7.9 � 3.4%; 4.1 � 1.6%; p = 0.007). NC was greater at IP in PPB (8.9 � 6.9%; p = 0.020) and PL (8.1 � 4.0%; p = 0.028) than CON (3.4 � 3.2%). 1028 Copyright � 2017 by the American College of Sports Medicine. Unauthorized reproduction of this article is prohibited. CONCLUSIONS: Exercise resulted in increased MCP-1 and the mobilization of specific monocyte subsets. Supplementation with PPB may augment the monocyte response. Funded by Kemin Foods, L.C. 3609 Board #56 June 3 9:30 AM - 11:00 AM Acute Resistance Training Induced Increases in Plasma Interleukin-6 are Volume-dependent Peter J. Ferrandi, Justin M. Quiles, Rocky Blanco, Alex Klemp, Chad Dolan, Arun Maharaj, Chun-Jung Huang, FACSM, Michael Whitehurst, FACSM, Michael C. Zourdos, FACSM. Florida Atlantic University, Boca Raton, FL. Email: email@example.com (No relationships reported) Exercise induces an inflammatory immune response, which is evidenced by the release of numerous cytokines. Specifically, interleukin-6 (IL-6) is of unique relevance, as exercise- induced release is mediated primarily by contracting skeletal muscle. Accordingly, elevations in IL-6 have been observed following various exercise modes, including resistance training. However, there is limited data comparing the IL-6 response between high-repetition (HR) and low-repetition (LR) resistance training programs. PURPOSE: To examine the effect of an acute bout of resistance training on changes in circulating IL-6 levels and to compare the response between volume-equated HR and LR training sessions. METHODS: Sixteen males (Age: 23�rs, Body Mass: 84.4�.3kg, Body Fat Percentage: 11.7�7%) with at least two yrs. of resistance training experience were counterbalanced by relative strength and assigned to one of two groups (high repetition-HR or low repetition-LR), which performed one resistance training session of back squat and bench press: HR (n=8): 4 sets of 12 repetitions at 60% of one- repetition maximum (1RM) or LR (n=8): 8 sets of 6 repetitions at 75% of 1RM. 10ml blood was obtained from the antecubital vein 30min. prior to and immediately following the resistance training session.. Samples were centrifuged and plasma was stored at -80篊 until further analysis. IL-6 concentrations were analyzed in duplicate, via a commercially available enzyme linked immunosorbent assay. A 2x2 repeated measures ANOVA with a Tukey post-hoc was used to determine changes in IL-6 response. Significance was set at p?0.05. RESULTS: A significant time effect was detected for IL-6 response in both groups: HR (0.71�19 to 1.39�18 pg/mL; p<0.001; +95.77%) and LR (0.53�10 to 1.27�10 pg/mL; p<0.001; +139.62%); however, no group differences (p=0.46) were observed. CONCLUSION: An acute resistance training bout incorporating multi-joint exercises effectively elicits a circulating IL-6 response. Further, in a trained population, this phenomenon appears to occur in a volume-dependent manner as the magnitude of IL-6 increase did not vary with repetition range. G-29 Free Communication/Poster ? Motor Control Across the Lifespan Saturday, June 3, 2017, 7:30 AM - 11:00 AM Room: Hall F 3610 Board #57 June 3 9:30 AM - 11:00 AM Motor Unit Action Potential Sizes of the First Dorsal Interosseous in Young and Older Individuals Adam J. Sterczala, Jonathan D. Miller, Anthony B. Ciccone, Michael A. Trevino, Justin X. Nicoll, Trent J. Herda. University of Kansas, Lawrence, KS. Email: firstname.lastname@example.org (No relationships reported) Slopes from the motor unit action potential size (MUAPsize) vs. recruitment threshold (RT) relationships provides a non-invasive measurement of MU sizes. As such, the slopes (APslopes) may be able to quantify age-related MU atrophy. PURPOSE: To determine if APslopes differed between young and old individuals. METHODS: Twenty two young (YG, age = 22.5�7 yrs) and ten aged (OG, 61.0�0 yrs) subjects completed the investigation. Surface electromyography signals were recorded from the first dorsal interosseous (FDI) during an isometric trapezoidal muscle action with the steady force plateau set at 50% maximal voluntary contraction (MVC). The signals were decomposed to yield MUAPsizes and RTs for each MU. The APslope was calculated via the MUAPsizes vs. RT relationships for MUs recruited between 10 and 50% MVC for each subject. Few MUs with RTs < 10% MVC were observed in young or old and, thus, these MUs were excluded from the slope calculation. FDI crosssectional area (CSA) and echo intensity (EI) were quantified using ultrasonography. Possible differences in APslope, CSA and EI between groups were examined with independent samples t-tests. RESULTS: OG demonstrated significantly reduced APslopes (OG: 0.033 � 0.010; YG: 0.048 � 0.020; p = 0.048) and greater EI (OG: 41.3 � 7.0 AU; YG: 50.6 � 7.5 AU; p = 0.002), however, CSA was similar between YG and OG (OG: 2.22 � 0.47 cm2; YG: 2.09 � 0.31 cm2; p = 0.438). CONCLUSION: The APslopes suggested non-uniform differences in MUAPsizes in relation to RT, likely due to reduced sizes of higher threshold MUs. Higher threshold MUs have been suggested to contain a greater proportion of type II muscle fibers, which demonstrate greater age induced atrophy than type I fibers commonly associated with lower threshold MUs. As such, the difference in APslopes suggested atrophy of higher threshold MUs in OG. In addition, OG?s elevated EI indicates greater infiltration of adipose and connective tissue into the muscle. Greater EI in combination with similar CSA may indicate a reduced contractile tissue volume in the OG, supporting the speculation that the APslope differences were due to MU atrophy. 3611 Board #58 June 3 9:30 AM - 11:00 AM Ankle Proprioception And Soccer Skills in Youth Recreational Players Li Li1, Jia Han2, Gordon Waddington3, Roger Adams3. 1Teacher Training College of Yangpu District Shanghai, Shanghai, China. 2Shanghai University of Sport, Shanghai, China. 3University of Canberra, Canberra, Australia. Email: email@example.com (No relationships reported) Evidence suggests that ankle proprioceptive ability is significantly correlated with soccer performance level. It has not been determined if ankle proprioception is associated with specific soccer skills in youth recreational soccer players. PURPOSE: to investigate the relationship between ankle proprioception and soccer skills in youth recreational players. METHODS: twenty-seven youth recreational soccer player (mean 14.8 years old, range 13-17), without ankle injury during the past 3 months, participated in this study. Their passing, shooting and dribbling skills were assessed by using the reliable and valid Soccer Skill Tests (Russell et al. 2010). Ankle proprioception was measured by using the active movement extend discrimination apparatus (AMEDA) in standing. 1029 Copyright � 2017 by the American College of Sports Medicine. Unauthorized reproduction of this article is prohibited.