Meredith G. Mock

Effects of pomegranate extract on blood flow and vessel diameter after high-intensity exercise in young, healthy adults

Abstract The effects of pomegranate extract (PE) supplementation were evaluated on high-intensity exercise performance, blood flow, vessel diameter, oxygen saturation (SPO2), heart rate (HR), and blood pressure (BP). In a randomized, crossover design, nineteen recreationally resistance-trained participants were randomly assigned to PE (1000 mg) or placebo (PL), which were consumed 30 min prior to a repeated sprint ability (RSA) test and repetitions to fatigue (RTF) on bench and leg press. The RSA consisted of ten six-second sprints on a friction-loaded cycle ergometer with 30 s recovery. Brachial artery blood flow and vessel diameter were assessed by ultrasound. Blood flow, vessel diameter, SPO2, HR, and BP were assessed at baseline, 30 min post ingestion, immediately post exercise (IPost), and 30 min post exercise (30minPost). With PE, blood flow significantly increased IPost RSA (mean difference = 18.49 mL min−1; P < .05), and IPost and 30minPost RTF (P < .05) according to confidence intervals (CI). Vessel diameter increased significantly 30minPost RSA according to CI and resulted in a significant interaction IPost and 30minPost RTF (P < .05). With PE, according to CI, average and peak power output increased significantly in sprint 5 of the RSA (P < .05). There was no significant difference between PE and PL for bench (P = .25) or leg press (P = .15) repetitions. Acute PE supplementation enhanced vessel diameter and blood flow, suggesting possible exercise performance enhancement from increased delivery of substrates and oxygen. The acute timing and capsule form of PE may be advantageous to athletic populations due to ergogenic effects, taste, and convenience.

Effects of Coffee and Caffeine Anhydrous Intake During Creatine Loading

Abstract Trexler, ET, Smith-Ryan, AE, Roelofs, EJ, Hirsch, KR, Persky, AM, and Mock, MG. Effects of coffee and caffeine anhydrous intake during creatine loading. J Strength Cond Res 30(5): 1438–1446, 2016—The purpose of this study was to determine the effect of 5 days of creatine (CRE) loading alone or in combination with caffeine anhydrous (CAF) or coffee (COF) on upper-body and lower-body strength and sprint performance. Physically active males (n = 54; mean ± SD; age = 20.1 ± 2.1 years; weight = 78.8 ± 8.8 kg) completed baseline testing, consisting of 1 repetition maximum (1RM) and repetitions to fatigue with 80% 1RM for bench press and leg press, followed by a repeated sprint test of five, 10-second sprints separated by 60-second rest on a cycle ergometer to determine peak power (PP) and total power (TP). At least 72 hours later, subjects were randomly assigned to supplement with CRE (5 g of CRE monohydrate, 4 times per day; n = 14), CRE + CAF (CRE +300 mg·d−1 of CAF; n = 13), CRE + COF (CRE +8.9 g of COF, yielding 303 mg of CAF; n = 13), or placebo (PLA; n = 14) for 5 days. Serum creatinine (CRN) was measured before and after supplementation, and on day 6, participants repeated pretesting procedures. Strength measures were improved in all groups (p ⩽ 0.05), with no significant time × treatment interactions. No significant interaction or main effects were observed for PP. For TP, a time × sprint interaction was observed (p ⩽ 0.05), with no significant interactions among treatment groups. A time × treatment interaction was observed for serum CRN values (p ⩽ 0.05) that showed increases in all groups except PLA. Four subjects reported mild gastrointestinal discomfort with CRE + CAF, with no side effects reported in other groups. These findings suggest that neither CRE alone nor in combination with CAF or COF significantly affected performance compared with PLA.

Longitudinal Body Composition Changes in NCAA Division I College Football Players

Abstract Trexler, ET, Smith-Ryan, AE, Mann, JB, Ivey, PA, Hirsch, KR, and Mock, MG. Longitudinal body composition changes in NCAA Division I college football players. J Strength Cond Res 31(1): 1–8, 2017—Many athletes seek to optimize body composition to fit the physical demands of their sport. American football requires a unique combination of size, speed, and power. The purpose of the current study was to evaluate longitudinal changes in body composition in Division I collegiate football players. For 57 players (mean ± SD, age = 19.5 ± 0.9 years, height = 186.9 ± 5.7 cm, weight = 107.7 ± 19.1 kg), body composition was assessed via dual-energy x-ray absorptiometry in the off-season (March-Pre), end of off-season (May), mid-July (Pre-Season), and the following March (March-Post). Outcome variables included weight, body fat percentage (BF%), fat mass, lean mass (LM), android and gynoid (GYN) fat, bone mineral content (BMC), and bone mineral density (BMD). For a subset of athletes (n = 13 out of 57), changes over a 4-year playing career were evaluated with measurements taken every March. Throughout a single year, favorable changes were observed for BF% (&Dgr; = −1.3 ± 2.5%), LM (&Dgr; = 2.8 ± 2.8 kg), GYN (&Dgr; = −1.5 ± 3.0%), BMC (&Dgr; = 0.06 ± 0.14 kg), and BMD (&Dgr; = 0.015 ± 0.027 g·cm−2, all p ⩽ 0.05). Across 4 years, weight increased significantly (&Dgr; = 6.6 ± 4.1 kg) and favorable changes were observed for LM (&Dgr; = 4.3 ± 3.0 kg), BMC (&Dgr; = 0.18 ± 0.17 kg), and BMD (&Dgr; = 0.033 ± 0.039 g·cm−2, all p ⩽ 0.05). Similar patterns in body composition changes were observed for linemen and non-linemen. Results indicate that well-trained collegiate football players at high levels of competition can achieve favorable changes in body composition, even late in the career, which may confer benefits for performance and injury prevention.

Metabolic characterization of overweight and obese adults

ABSTRACT Objectives: Traditional evaluations of metabolic health may overlook underlying dysfunction in individuals who show no signs of insulin resistance or dyslipidemia. The purpose of this study was to characterize metabolic health in overweight and obese adults using traditional and non-traditional cardiometabolic variables. A secondary purpose was to evaluate differences between overweight/obese and male/female cohorts, respectively. Methods: Forty-nine overweight and obese adults (Mean ± SD; Age = 35.0 ± 8.9 yrs; Body mass index = 33.6 ± 5.2 kg·m−2; Percent body fat [%fat] = 36.7 ± 7.9%) were characterized. Body composition (fat mass [FM], lean mass [LM], %fat) was calculated using a 4-compartment model; visceral adipose tissue (VAT) was quantified using B-mode ultrasound. Resting metabolic rate (RMR) and respiratory exchange ratio (RER) were evaluated using indirect calorimetry. Fasted blood and saliva samples were analyzed for total cholesterol (TC), high-density lipoproteins (HDL), low-density lipoproteins (LDL), triglycerides (TRG), glucose (GLUC), insulin, leptin, estradiol, and cortisol. Results: The prevalence of individuals with two or more cardiometabolic risk factors increased from 13%, using traditional risk factors (GLUC, TRG, HDL), to 80% when non-traditional metabolic factors (VAT, LM, RMR, RER, TC, LDL, HOMA-IR) were considered. Between overweight/obese, there were no significant differences in %fat (p = 0.152), VAT (p = 0.959), RER (p = 0.493), lipids/GLUC (p > 0.05), insulin (p = 0.143), leptin (p = 0.053), or cortisol (p = 0.063); obese had higher FM, LM, RMR, and estradiol (p < 0.01). Males had greater LM, RMR, and TRG (p < 0.01); females had greater %fat, and leptin (p < 0.001). There were no significant sex differences in RER, estradiol, insulin, or cortisol (p > 0.05). Conclusions: Evaluating metabolic health beyond BMI and traditional cardiometabolic risk factors can give significant insights into metabolic status. Due to high variability in metabolic health in overweight and obese adults and inherent sex differences, implementation of body composition and visceral fat measures in the clinical setting can improve early identification and approaches to disease prevention.

Cordyceps militaris Improves Tolerance to High-Intensity Exercise After Acute and Chronic Supplementation

ABSTRACT To determine the effects of a mushroom blend containing Cordyceps militaris on high-intensity exercise after 1 and 3 weeks of supplementation. Twenty-eight individuals (Mean ± standard deviation [SD]; Age = 22.7 ± 4.1 yrs; Height = 175.4 ± 8.7 cm; Weight = 71.6 ± 12.0 kg) participated in this randomized, repeated measures, double-blind, placebo-controlled design. Maximal oxygen consumption (VO2max), time to exhaustion (TTE), and ventilatory threshold (VT) were measured during a maximal graded exercise test on a cycle ergometer. Relative peak power output (RPP), average power output (AvgP), and percent drop (%drop) were recorded during a 3 minute maximal cycle test with resistance at 4.5% body weight. Subjects consumed 4 g·d−1 mushroom blend (MR) or maltodextrin (PL) for 1 week. Ten volunteers supplemented for an additional 2 weeks. Exercise tests were separated by at least 48 hours and repeated following supplementation periods. One week of supplementation elicited no significant time × treatment interaction for VO2max (p = 0.364), VT (p = 0.514), TTE (p = 0.540), RPP (p = 0.134), AvgP (p = 0.398), or %drop (p = 0.823). After 3 weeks, VO2max significantly improved (p = 0.042) in MR (+4.8 ml·kg−1·min−1), but not PL (+0.9 ml·kg−1·min−1). Analysis of 95% confidence intervals revealed significant improvements in TTE after 1- (+28.1 s) and 3 weeks (+69.8 s) in MR, but not PL, with additional improvements in VO2max (+4.8 ml·kg−1·min−1) and VT (+0.7 l·min−1) after 3 weeks. Acute supplementation with a Cordyceps militaris containing mushroom blend may improve tolerance to high-intensity exercise; greater benefits may be elicited with consistent chronic supplementation.

Validity of a Multi-compartment Body Composition Model Using Body Volume Derived from Dual-Energy X-ray Absorptiometry: 3715 Board #154 June 4, 8: 00 AM - 9: 30 AM.

Measuring body composition may serve as an important clinical tool in assessing health risks. A four-compartment (4C) model utilizing body mass, body volume (BV), total body water (TBW), and bone mineral content (BMC) is a widely accepted criterion method for predicting body composition. BV is commonly assessed using air displacement plethysmography (BodPod). However, dual-energy x-ray absorptiometry (DXA) has been proposed as an alternative method for BV, reducing time and equipment required for a multi-compartment model. PURPOSE: To assess the validity of a DXA-derived body volume 4C model for calculation of percent body fat (%BF), fat mass (FM), and lean mass (LM). METHODS: A total sample of 126 men and women (Mean ± SD; Age: 35.8 ± 9.4 years; Body Mass: 97.31 ± 20.4 kg; Height: 176.04 ± 9.2 cm) completed a 4C body composition reference assessment, including BV from Bodpod, TBW from bioelectrical impedance spectroscopy, and BMC from DXA. Using a sample of 99 subjects, a DXA-derived body volume 4C model (4C DXA) was created by linearly regressing BodPod BV with DXA FM, LM, and BMC as independent factors. The 4C DXA model was validated in a sub-sample of 27 subjects. RESULTS: The density coefficients of FM, LM, and BMC determined to predict BV were 0.84 (p CONCLUSIONS: The 4C DXA model using the determined coefficients was demonstrated to be a valid method of estimating FM, LM, and %BF when compared to a traditional 4C model. The alternative method of predicting BV using DXA may eliminate the need for a BodPod when using a 4C model to assess body composition.

Fat-Free Mass Index in NCAA Division I and II Collegiate American Football Players

Abstract Trexler, ET, Smith-Ryan, AE, Blue, MNM, Schumacher, RM, Mayhew, JL, Mann, JB, Ivey, PA, Hirsch, KR, and Mock, MG. Fat-free mass index in NCAA Division I and II collegiate American football players. J Strength Cond Res 31(10): 2719–2727, 2017—Fat-free mass index (FFMI) is a height-adjusted assessment of fat-free mass (FFM), with previous research suggesting a natural upper limit of 25 kg·m−2 in resistance trained male athletes. The current study evaluated upper limits for FFMI in collegiate American football players (n = 235) and evaluated differences between positions, divisions, and age groups. The sample consisted of 2 National Collegiate Athletic Association Division I teams (n = 78, n = 69) and 1 Division II team (n = 88). Body composition was assessed via dual-energy x-ray absorptiometry and used to calculate FFMI; linear regression was used to normalize values to a height of 180 cm. Sixty-two participants (26.4%) had height-adjusted FFMI values above 25 kg·m−2 (mean = 23.7 ± 2.1 kg·m−2; 97.5th percentile = 28.1 kg·m−2). Differences were observed among position groups (p < 0.001; &eegr;2 = 0.25), with highest values observed in offensive linemen (OL) and defensive linemen (DL) and lowest values observed in offensive and defensive backs. Fat-free mass index was higher in Division I teams than Division II team (24.3 ± 1.8 kg·m−2 vs. 23.4 ± 1.8 kg·m−2; p < 0.001; d = 0.49). Fat-free mass index did not differ between age groups. Upper limit estimations for FFMI seem to vary by position; although the 97.5th percentile (28.1 kg·m−2) may represent a more suitable upper limit for the college football population as a whole, this value was exceeded by 6 linemen (3 OL and 3 DL), with a maximal observed value of 31.7 kg·m−2. Football practitioners may use FFMI to evaluate an individuals capacity for additional FFM accretion, suitability for a specific position, potential for switching positions, and overall recruiting assessment.

Effects of coffee and caffeine anhydrous on strength and sprint performance

Caffeine and coffee are widely used among active individuals to enhance performance. The purpose of the current study was to compare the effects of acute coffee (COF) and caffeine anhydrous (CAF) i...

Effects of macronutrient intake on fuel utilization: potential sex differences.

Background Evidence suggests that women oxidize more fat for fuel at rest than males. Potential sex differences in fuel utilization during exercise remain unclear. Alterations in diet may influence substrate utilization by altering substrate availability and metabolic enzyme activity. Reduced carbohydrate (CHO) intake has been shown to lower respiratory exchange ratio (RER) over time, which may improve aerobic endurance. The purpose of this study was to explore potential sex differences in the relationship between habitual macronutrient distribution and substrate utilization during exercise.

The effects of pomegranate extract on anaerobic exercise performance & cardiovascular responses

Background During exercise, there is an increased demand for oxygen. Increasing blood flow may provide an ergogenic effect. Dietary nitrate supplementation, such as pomegranate extract (PE), has been linked to reduced vascular resistance, enhanced vasodilation, and increased blood flow to possibly improve exercise efficiency. The purpose of this study was to evaluate the effects of acute PE supplementation on anaerobic exercise, flow mediated dilation (FMD), oxygen saturation (SP02), heart rate (HR), and blood pressure (BP).