Countermovement jump, handgrip, and balance performance change during euhydration, mild-dehydration, rehydration, and ad libitum drinking.

Objective: To examine the effects of euhydration, mild-dehydration, rehydration, and ad libitum drinking on countermovement jump (CMJ), handgrip strength, and performance of balance error scoring system test (BESS). Methods: Eighteen healthy male subjects (mean[M]±standard deviation[SD]; age, 23±3y; body mass, 80.1 ± 9.7 kg; height, 175.8 ± 5.7 cm) participated in this study. Participants reported to the laboratory to perform CMJ, handgrip strength, and BESS with different hydration statuses (euhydrated, EUH; when they initially sensed thirst, THIRST; dehydrated, DEH; following 30 minutes of rehydration, REH; and following 24-h ad libitum drinking, AD). Results: CMJ at EUH (M±SD; 54.6 ± 3.0 cm) was significantly higher than DEH (52.8 ± 3.0 cm, p = 0.027) and REH (52.6 ± 2.8 cm, p < 0.001). However, there was no difference between DEH and REH (p = 0.643). CMJ at THIRST (54.9 ± 3.0 cm, p = 0.004) was higher than REH. Also, AD (53.8 ± 2.8 cm, p = 0.027) was higher than REH. In left handgrip strength, THIRST (48.6 ± 9.5 kg) was higher than EUH (46.7 ± 10.1 kg, p = 0.018), DEH (45.8 ± 10.0 kg, p = 0.013), REH (46.1 ± 9.5 kg, p = 0.004), and AD (47.1 ± 9.7 kg, p = 0.05). Additionally, in the single-leg stance on a foam pad, more BESS errors were found at THIRST (6 ± 2) compared to EUH (5 ± 2, p = 0.007) and AD (5 ± 2, p = 0.002). Conclusion: The findings of this study were: ∼2% of mild dehydration induced by 24-h fluid restriction decreased lower body power measured by CMJ, acute rehydration did not restore the loss of lower body power induced by dehydration, and ∼0.5-0.9% of dehydration did not decrease lower body power.

Resistance Training and Milk-Substitution Enhance Body Composition and Bone Health in Adolescent Girls.

Background: Increased soft-drink consumption has contributed to poor calcium intake with 90% of adolescent girls consuming less than the RDA for calcium.Purpose/objectives: The purpose of this investigation was to determine the independent and additive effects of two interventions (milk and resistance training) on nutrient adequacy, body composition, and bone health in adolescent girls.Methods: The experimental design consisted of four experimental groups of adolescent girls 14-17 years of age: (1) Milk + resistance training [MRT]; n = 15; (2) Resistance training only [RT]; n = 15; (3) Milk only [M] n = 20; (4) Control [C] n = 16. A few significant differences were observed at baseline between the groups for subject characteristics. Testing was performed pre and post-12 week training period for all groups. Milk was provided (3, 8 oz servings) for both the MRT and the M groups. The MRT group and the RT groups performed a supervised periodized resistance training program consisting of supervised one-hour exercise sessions 3 d/wk (M, W, F) for 12 wk. Baseline dietary data was collected utilizing the NUT-P-FFQ and/or a 120 item FFQ developed by the Fred Hutchinson Cancer Research Center (Seattle, Washington). Body composition was measured in the morning after an overnight fast using dual-energy X-ray absorptiometry (DXA) with a total body scanner (ProdigyTM, Lunar Corporation, Madison, WI). A whole body scan for bone density and lumbar spine scans were performed on all subjects. Maximal strength of the upper and lower body was assessed via a one-repetition maximum (1-RM) squat and bench press exercise protocols. Significance was set at P ≤ 0.05.Results: Significant differences in nutrient intakes between groups generally reflected the nutrient composition of milk with greater intakes of protein and improved nutrient adequacy for several B vitamins, vitamin A, vitamin D, calcium, magnesium, phosphorus, potassium, and zinc. Mean calcium intake was 758 and 1581 mg/d, in the non-milk and milk groups, respectively, with 100% of girls in the milk groups consuming > RDA of 1300 mg/d. There were no effects of milk on body composition or muscle performance, but resistance training had a main effect and significantly increased body mass, lean body mass, muscle strength, and muscle endurance. There was a main effect of milk and resistance training on several measures of bone mineral density (BMD). Changes in whole body BMD in the M, RT, MRT, and CON were 0.45, 0.52, 1.32, and -0.19%, respectively (P < 0.01).Conclusions: Over the course of 12 weeks the effects of 1300 mg/d of calcium in the form of fluid milk combined with a heavy resistance training program resulted in the additive effects of greater nutrient adequacy and BMD in adolescent girls. While further studies are needed, combining increased milk consumption with resistance training appears to optimize bone health in adolescent girls.

The Relationship Between Physical Activity and Executive Functions Among Youth in Low-Income Urban Schools in the Northeast and Southwest United States.

The purpose of this study was to examine if physical activity is related to greater executive functions among youth in poverty. Executive functions (cognitive flexibility, inhibition, and working memory) and physical activity were measured in participants (N = 149) in the fifth to eighth grade from three schools located in high-poverty districts. Pearson correlations revealed a statistically significant correlation between physical activity and cognitive flexibility (r = .18, p < .05). Hierarchical multiple regressions revealed that physical activity significantly improved prediction for cognitive flexibility, R2 = .09, F(6, 142) = 2.26, p = .041, adjusted R2 = .05, above sex, maturity, and school district. A two-way multivariate analysis of covariance revealed statistically significant differences in working memory in more active youth compared with less active but no statistically significant differences in cognitive flexibility or inhibition (p < .05). Greater physical activity is associated with greater working memory among youth in poverty.

Ceragenin CSA13 Reduces Clostridium difficile Infection in Mice by Modulating the Intestinal Microbiome and Metabolites.

BACKGROUND & AIMS: Clostridium difficile induces intestinal inflammation by releasing toxins A and B. The antimicrobial compound cationic steroid antimicrobial 13 (CSA13) has been developed for treating gastrointestinal infections. The CSA13-Eudragit formulation can be given orally and releases CSA13 in the terminal ileum and colon. We investigated whether this form of CSA13 reduces C difficile infection (CDI) in mice. METHODS: C57BL/6J mice were infected with C difficile on day 0, followed by subcutaneous administration of pure CSA13 or oral administration of CSA13-Eudragit (10 mg/kg/d for 10 days). Some mice were given intraperitoneal vancomycin (50 mg/kg daily) on days 0-4 and relapse was measured after antibiotic withdrawal. The mice were monitored until day 20; colon and fecal samples were collected on day 3 for analysis. Blood samples were collected for flow cytometry analyses. Fecal pellets were collected each day from mice injected with CSA13 and analyzed by high-performance liquid chromatography or 16S sequencing; feces were also homogenized in phosphate-buffered saline and fed to mice with CDI via gavage. RESULTS: CDI of mice caused 60% mortality, significant bodyweight loss, and colonic damage 3 days after infection; these events were prevented by subcutaneous injection of CSA13 or oral administration CSA13-Eudragit. There was reduced relapse of CDI after administration of CSA13 was stopped. Levels of CSA13 in feces from mice given CSA13-Eudragit were significantly higher than those of mice given subcutaneous CSA13. Subcutaneous and oral CSA13 each significantly increased the abundance of Peptostreptococcaceae bacteria and reduced the abundance of C difficile in fecal samples of mice. When feces from mice with CDI and given CSA13 were fed to mice with CDI that had not received CSA13, the recipient mice had significantly increased rates of survival. CSA13 reduced fecal levels of inflammatory metabolites (endocannabinoids) and increased fecal levels of 4 protective metabolites (ie, citrulline, 3-aminoisobutyric acid, retinol, and ursodeoxycholic acid) in mice with CDI. Oral administration of these CSA13-dependent protective metabolites reduced the severity of CDI. CONCLUSIONS: In studies of mice, we found the CSA13-Eudragit formulation to be effective in eradicating CDI by modulating the intestinal microbiota and metabolites.

Cold-water immersion blunts and delays increases in circulating testosterone and cytokines post-resistance exercise.

INTRODUCTION: Cold-water immersion (CWI) is often used to promote recovery by reducing exercise-induced muscle damage, soreness, and inflammation. However, recent reports have cautioned that CWI may attenuate the adaptive response to resistance training. PURPOSE: To determine the effect of post resistance-exercise CWI on circulating free testosterone (T) and cytokine (IL-6 and TNF-α) response. METHODS: Using a randomized and counterbalanced repeated-measures design, 11 resistance-trained men completed two workouts (6 sets of 10 repetitions of back squats at 80% of maximum load) a week apart after which they took part in either 15 min of CWI (15 °C) or passive recovery. T, IL-6, and TNFα were measured in blood samples taken before (PRE) and 5 (5POST), 15 (15POST), 30 (30POST), and 60 (60POST) min post-exercise and compared between treatments and over time. RESULTS: For T, a significant interaction effect of condition over time (p = 0.030) as well as greater relative concentrations of T in CON (Δ9.2%) than CWI (Δ-0.5%, p = 0.049) at 30POST were observed. In addition, at 60POST, T dropped below PRE values in CWI (Δ-10.4%, p = 0.028) but not in CON (Δ-1.6%, p = 0.850). A suppressed cytokine response was observed after CWI in IL-6 at 30POST (CWI: Δ4.9%, CON: Δ47.5%, p = 0.041) and TNFα at 15POST (CWI: Δ5.3%, CON: Δ17.0%, p = 0.022). CONCLUSIONS: CWI blunted the T and cytokine response after a bout of resistance exercise. These results indicate that CWI results in an altered anabolic response and may help to explain the previous observation of attenuated hypertrophy when CWI is used after resistance exercise.

Monitoring Blood Biomarkers and Training Load Throughout a Collegiate Soccer Season.

Huggins, RA, Fortunati, AR, Curtis, RM, Looney, DP, West, CA, Lee, EC, Fragala, MS, Hall, ML, and Casa, DJ. Monitoring blood biomarkers and training load throughout a collegiate soccer season. J Strength Cond Res 33(11): 3065-3077, 2019-This observational study aimed to characterize the responses of a comprehensive panel of biomarkers, observed ranges, training load (TL) metrics, and performance throughout the collegiate soccer season (August-November). Biomarkers (n = 92) were collected before the start of pre-season (PS), in-season weeks (W)1, W4, W8, and W12 in NCAA Division I male soccer players (n = 20, mean ± SD; age = 21 ± 1 years, height = 180 ± 6 cm, body mass = 78.19 ± 6.3 kg, body fat = 12.0 ± 2.6%, VO2max 51.5 ± 5.1 ml·kg·min). Fitness tests were measured at PS, and W12 and TL was monitored daily. Changes in biomarkers and performance were calculated via separate repeated-measures analysis of variance. Despite similar fitness (p > 0.05), endocrine, muscle, inflammatory, and immune markers changed over time (p < 0.05). Total and free testosterone was lower in W1 vs. PS, whereas free cortisol remained unchanged at PS, W1, and W4 (>0.94 mg·dL). Oxygen transport and iron metabolism markers remained unchanged except for HCT (W1 vs. PS) and total iron binding capacity (W8-W12 vs. W1). Hepatic markers albumin, globulin, albumin:globulin, and total protein levels were elevated (p < 0.05) at W12 vs. W1, whereas aspartate aminotransferase and alanine aminotransferase levels were elevated at W1-W12 and W8-W12 vs. PS, respectively. Vitamin E, zinc, selenium, and calcium levels were elevated (p < 0.05) at W12 vs. W1, whereas Vitamin D was decreased (p < 0.05). Fatty acids and cardiovascular markers (omega-3 index, cholesterol:high-density lipoprotein [HDL], docosahexenoic acid, low-density lipoprotein [LDL], direct LDL, non-HDL, ApoB) were reduced at W1 vs. PS (p ≤ 0.05). Immune, lipid, and muscle damage biomarkers were frequently outside clinical reference ranges. Routine biomarker monitoring revealed subclinical and clinical changes, suggesting soccer-specific reference ranges. Biomarker monitoring may augment positive adaptation and reduce injuries from stressors incurred during soccer.

Fidaxomicin and OP-1118 Inhibit Clostridium difficile Toxin A- and B-Mediated Inflammatory Responses via Inhibition of NF-κB Activity.

Clostridium difficile causes diarrhea and colitis by releasing toxin A and toxin B. In the human colon, both toxins cause intestinal inflammation and stimulate tumor necrosis factor alpha (TNF-α) expression via the activation of NF-κB. It is well established that the macrolide antibiotic fidaxomicin is associated with reduced relapses of C. difficile infection. We showed that fidaxomicin and its primary metabolite OP-1118 significantly inhibited toxin A-mediated intestinal inflammation in mice in vivo and toxin A-induced cell rounding in vitro We aim to determine whether fidaxomicin and OP-1118 possess anti-inflammatory effects against toxin A and toxin B in the human colon and examine the mechanism of this response. We used fresh human colonic explants, NCM460 human colonic epithelial cells, and RAW264.7 mouse macrophages to study the mechanism of the activity of fidaxomicin and OP-1118 against toxin A- and B-mediated cytokine expression and apoptosis. Fidaxomicin and OP-1118 dose-dependently inhibited toxin A- and B-induced TNF-α and interleukin-1ß (IL-1ß) mRNA expression and histological damage in human colonic explants. Fidaxomicin and OP-1118 inhibited toxin A-mediated NF-κB phosphorylation in human and mouse intestinal mucosae. Fidaxomicin and OP-1118 also inhibited toxin A-mediated NF-κB phosphorylation and TNF-α expression in macrophages, which was reversed by the NF-κB activator phorbol myristate acetate (PMA). Fidaxomicin and OP-1118 prevented toxin A- and B-mediated apoptosis in NCM460 cells, which was reversed by the addition of PMA. PMA reversed the cytoprotective effect of fidaxomicin and OP-1118 in toxin-exposed human colonic explants. Fidaxomicin and OP-1118 inhibit C. difficile toxin A- and B-mediated inflammatory responses, NF-κB phosphorylation, and tissue damage in the human colon.

Adding Resistance Training to the Standard of Care for Inpatient Substance Abuse Treatment in Men With Human Immunodeficiency Virus Improves Skeletal Muscle Health Without Altering Cytokine Concentrations.

Vingren, JL, Curtis, JH, Levitt, DE, Duplanty, AA, Lee, EC, McFarlin, BK, and Hill, DW. Adding resistance training to the standard of care for inpatient substance abuse treatment in men with human immunodeficiency virus improves skeletal muscle health without altering cytokine concentrations. J Strength Cond Res 32(1): 76-82, 2018-Substance abuse and human immunodeficiency virus (HIV) infection can independently lead to myopathy and related inflammatory alterations; importantly, these effects seem to be additive. Resistance training (RT) can improve muscle health in people living with HIV (PLWH), but the efficacy of this intervention has not been examined for PLWH recovering from substance abuse. The purpose of this study was to determine the effect of RT on muscle health markers (mass, strength, and power) and basal circulating biomarkers for men living with HIV undergoing substance abuse treatment. Men living with HIV undergoing 60-day inpatient substance abuse treatment completed either RT (3×/wk) or no exercise training (control) for 6 weeks. Muscle mass, strength, and power, and fasting circulating cytokines (interferon γ, tumor necrosis factor-α, interleukin (IL)-1ß, IL-2, IL-4, IL-6, and IL-10), vascular cellular adhesion molecule-1, and cortisol were measured before (PRE) and after (POST) the 6-week period. Both groups received the standard of care for HIV and substance abuse treatment determined by the inpatient facility. Muscle mass, strength, and power increased (p ≤ 0.05) from PRE to POST for RT but were unchanged for control. No differences were found for circulating biomarkers. Adding RT to the standard of care for substance abuse treatment improved aspects of muscle health (mass, strength, and power) in men living with HIV. These improvements are associated with a lower risk of a number of health conditions. Therefore, practitioners should consider implementing RT interventions as part of substance abuse treatment programs in this population to help manage long-term health.

Relationships between hydration biomarkers and total fluid intake in pregnant and lactating women.

INTRODUCTION: Previous research established significant relationships between total fluid intake (TFI) and urinary biomarkers of the hydration process in free-living males and females; however, the nature of this relationship is not known for pregnant (PREG) and lactating (LACT) women. PURPOSE: To determine the relationship between urinary and hematological hydration biomarkers with TFI in PREG and LACT. METHODS: Eighteen PREG/LACT (age: 31 ± 3 years, pre-pregnancy BMI: 24.26 ± 5.85 kg m-2) collected 24-h urine samples, recorded TFI, and provided a blood sample at 5 time points (15 ± 2, 26 ± 1, 37 ± 1 weeks gestation, 3 ± 1 and 9 ± 1 weeks postpartum during lactation); 18 pair-matched non-pregnant (NP), non-lactating (NL) women (age: 29 ± 4 years, BMI: 24.1 ± 3.7 kg m-2) provided samples at similar time intervals. Twenty-four-hour urine volume (U VOL), osmolality (U OSM), specific gravity (U SG), and color (U COL) were measured. Hematocrit, serum osmolality (S OSM), and serum total protein (S TP) were measured in blood. RESULTS: Significant relationships were present between TFI and urinary biomarkers in all women (P < 0.004); these relationships were not different between PREG and NP, and LACT and NL, except U VOL in PREG (P = 0.0017). No significant relationships between TFI and hematological biomarkers existed (P > 0.05). CONCLUSION: Urinary biomarkers of hydration, but not hematological biomarkers, have a strong relationship with TFI in PREG, LACT, NP, and NL women. These data suggest that urinary biomarkers of hydration reflect TFI during pregnancy and breast-feeding.

Exertional Hyponatremia and Serum Sodium Change During Ultraendurance Cycling.

INTRODUCTION: Exertional hyponatremia (EH) during prolonged exercise involves all avenues of fluid-electrolyte gain and loss. Although previous research implicates retention of excess fluid, EH may involve either loss, gain, or no change of body mass. Thus, the etiology, predisposing factors, and recommendations for prevention are vague-except for advice to avoid excessive drinking. PURPOSE: This retrospective field study presents case reports of two unacquainted recreational cyclists (LC, 31y and AM, 39 years) who began exercise with normal serum electrolytes but finished a summer 164-km ride (ambient, 34±5°C) with a serum [Na+] of 130 mmol/L. METHODS: To clarify the etiology of EH, their pre- and post-exercise measurements were compared to a control group (CON) of 31 normonatremic cyclists (mean ± SD; 37±6 years; 141±3 mmol Na+/L). RESULTS: Anthropomorphic characteristics, exercise time, and post-exercise ratings of thermal sensation, perceived exertion and muscle cramp were similar for LC, AM and CON. These two hyponatremic cyclists consumed a large and similar volume of fluid (191 and 189 ml/kg), experienced an 11 mmol/L decrease of serum [Na+], reported low thirst sensations; however, LC gained 3.1 kg (+4.3% of body mass) during 8.9 hr of exercise and AM maintained body mass (+0.1kg, +0.1%, 10.6h). In the entire cohort (n = 33), post-event serum [Na+] was strongly correlated with total fluid intake (R2 = 0.45, p < .0001), and correlated moderately with dietary sodium intake (R2=0.28, p = .004) and body mass change (R2 = 0.22, p = .02). Linear regression analyses predicted the threshold of EH onset (<135 mmol Na+/L) as 168 ml fluid/kg. CONCLUSIONS: The wide range of serum [Na+] changes (+6 to -11 mmol/L) led us to recommend an individualized rehydration plan to athletes because the interactions of factors were complex and idiosyncratic.

Biomarkers in Sports and Exercise: Tracking Health, Performance, and Recovery in Athletes.

Biomarker discovery and validation is a critical aim of the medical and scientific community. Research into exercise and diet-related biomarkers aims to improve health, performance, and recovery in military personnel, athletes, and lay persons. Exercise physiology research has identified individual biomarkers for assessing health, performance, and recovery during exercise training. However, there are few recommendations for biomarker panels for tracking changes in individuals participating in physical activity and exercise training programs. Our approach was to review the current literature and recommend a collection of validated biomarkers in key categories of health, performance, and recovery that could be used for this purpose. We determined that a comprehensive performance set of biomarkers should include key markers of (a) nutrition and metabolic health, (b) hydration status, (c) muscle status, (d) endurance performance, (e) injury status and risk, and (f) inflammation. Our review will help coaches, clinical sport professionals, researchers, and athletes better understand how to comprehensively monitor physiologic changes, as they design training cycles that elicit maximal improvements in performance while minimizing overtraining and injury risk.

Precision, Accuracy, and Performance Outcomes of Perceived Exertion vs. Heart Rate Guided Run-training.

Johnson, EC, Pryor, RR, Casa, DJ, Ellis, LA, Maresh, CM, Pescatello, LS, Ganio, MS, Lee, EC, and Armstrong, LE. Precision, accuracy, and performance outcomes of perceived exertion vs. heart rate guided run-training. J Strength Cond Res 31(3): 630-637, 2017-The purpose of this investigation was to compare run-prescription by heart rate (HR) vs. rating of perceived exertion (RPE) during 6 weeks to determine which is superior for consistent achievement of target intensities and improved performance. Forty untrained men participated in this laboratory-controlled and field-controlled trial. Participants were divided into heart rate (HRTG) and rating of perceived exertion training groups (RPETG). All underwent maximal-graded exercise testing and a 12-minute run test before and after training. Intensity was prescribed as either a target HR or RPE that corresponded to 4 relative intensity levels: 45, 60, 75, and 90% V[Combining Dot Above]O2 reserve (V[Combining Dot Above]O2R). Mean exercise intensity over the 6 weeks did not differ between HRTG (65.6 ± 7.2%HRR) and RPETG (61.9 ± 9.0%HRR). V[Combining Dot Above]O2max (+4.1 ± 2.5 ml·kg·min) and 12 minutes run distance (+240.1 ± 150.1 m) improved similarly in HRTG and RPETG (p > 0.05). HRTG displayed lower coefficients of variation (CV) (5.9 ± 4.1%, 3.3 ± 3.8%, and 3.0 ± 2.2%) and %error (4.1 ± 4.7%, 2.3 ± 4.1% and 2.6 ± 3.2%) at 45, 60, and 75% V[Combining Dot Above]O2R compared with RPETG (CV 11.1 ± 5.0%, 7.7 ± 4.1% and 5.6 ± 3.2%; all p < 0.005) %error (15.7 ± 9.2%, 10.6 ± 9.2% and 6.7 ± 3.2%; all p < 0.001), respectively. Overall, HR-prescribed and RPE-prescribed run-training resulted in similar exercise intensity and performance outcomes over 6 weeks. Differences in the CV and %error suggest use of HR monitoring for individuals that are new to running as it improves precision and accuracy but does not increase performance improvements across 6 weeks.

Effect of Caffeine on Perceived Soreness and Functionality Following an Endurance Cycling Event.

Caldwell, AR, Tucker, MA, Butts, CL, McDermott, BP, Vingren, JL, Kunces, LJ, Lee, EC, Munoz, CX, Williamson, KH, Armstrong, LE, and Ganio, MS. Effect of caffeine on perceived soreness and functionality following an endurance cycling event. J Strength Cond Res 31(3): 638-643, 2017-Caffeine can reduce muscle pain during exercise; however, the efficacy of caffeine in improving muscle soreness and recovery from a demanding long-duration exercise bout has not been established. The purpose of this study was to investigate the effects of caffeine intake on ratings of perceived muscle soreness (RPMS) and perceived lower extremity functionality (LEF) following the completion of a 164-km endurance cycling event. Before and after cycling RPMS (1-to-6; 6 = severe soreness) and LEF (0-to-80; 80 = full functionality) were assessed by questionnaires. Subjects ingested 3 mg/kg body mass of caffeine or placebo pills in a randomized, double-blind fashion immediately after the ride and for the next 4 mornings (i.e., ∼800 hours) and 3 afternoons (i.e., ∼1200 hours). Before each ingestion, RPMS and LEF were assessed. Afternoon ratings of LEF were greater with caffeine ingestion the first day postride (65.0 ± 6.1 vs. 72.3 ± 6.7; for placebo and caffeine, respectively; p = 0.04), but at no other time points (p > 0.05). The caffeine group tended to have lower overall RPMS in the afternoon versus placebo (i.e., main effect of group; 1.1 ± 0.2 vs. 0.5 ± 0.2; p = 0.09). Afternoon RPMS for the legs was significantly lower in the caffeine group (main effect of caffeine; 1.3 ± 0.2 vs. 0.5 ± 0.3; p = 0.05). In conclusion, ingesting caffeine improved RPMS for the legs, but not LEF in the days following an endurance cycling event. Athletes may benefit from ingesting caffeine in the days following an arduous exercise bout to relieve feelings of soreness and reduced functionality.

Blood Hemostatic Changes During an Ultraendurance Road Cycling Event in a Hot Environment.

OBJECTIVE: This study aims to examine blood hemostatic responses to completing a 164-km road cycling event in a hot environment. METHODS: Thirty-seven subjects (28 men and 9 women; 51.8±9.5 [mean±SD] y) completed the ride in 6.6±1.1 hours. Anthropometrics (height, body mass [taken also during morning of the ride], percent body fat [%]) were collected the day before the ride. Blood samples were collected on the morning of the ride (PRE) and immediately after (IP) the subject completed the ride. Concentrations of platelet, platelet activation, coagulation, and fibrinolytic markers (platelet factor 4, ß-thromboglobulin, von Willebrand factor antigen, thrombin-antithrombin complex, thrombomodulin, and D-Dimer) were measured. Associations between changes from PRE- to IP-ride were examined as a function of event completion time and subject characteristics (demographics and anthropometrics). RESULTS: All blood hemostatic markers increased significantly (P < .001) from PRE to IP. After controlling for PRE values, finishing time was negatively correlated with platelet factor 4 (r = 0.40; P = .017), while percent body fat (%BF) was negatively correlated with thrombin-antithrombin complex (r = -0.35; P = .038) and to thrombomodulin (r = -0.36; P = .036). In addition, male subjects had greater concentrations of thrombin-antithrombin complex (d = 0.63; P < .05) and natural logarithm thrombomodulin (d = 6.42; P < .05) than female subjects. CONCLUSION: Completing the 164-km road cycling event in hot conditions resulted in increased concentrations of platelet, platelet activation, coagulation, and fibrinolytic markers in both men and women. Although platelet activation and coagulation occurred, the fibrinolytic system markers also increased, which appears to balance blood hemostasis and may prevent clot formation during exercise in a hot environment.

Probiotic Saccharomyces boulardii CNCM I-745 prevents outbreak-associated Clostridium difficile-associated cecal inflammation in hamsters.

C. difficile infection (CDI) is a common debilitating nosocomial infection associated with high mortality. Several CDI outbreaks have been attributed to ribotypes 027, 017, and 078. Clinical and experimental evidence indicates that the nonpathogenic yeast Saccharomyces boulardii CNCM I-745 (S.b) is effective for the prevention of CDI. However, there is no current evidence suggesting this probiotic can protect from CDI caused by outbreak-associated strains. We used established hamster models infected with outbreak-associated C. difficile strains to determine whether oral administration of live or heat-inactivated S.b can prevent cecal tissue damage and inflammation. Hamsters infected with C. difficile strain VPI10463 (ribotype 087) and outbreak-associated strains ribotype 017, 027, and 078 developed severe cecal inflammation with mucosal damage, neutrophil infiltration, edema, increased NF-κB phosphorylation, and increased proinflammatory cytokine TNFα protein expression. Oral gavage of live, but not heated, S.b starting 5 days before C. difficile infection significantly reduced cecal tissue damage, NF-κB phosphorylation, and TNFα protein expression caused by infection with all strains. Moreover, S.b-conditioned medium reduced cell rounding caused by filtered supernatants from all C. difficile strains. S.b-conditioned medium also inhibited toxin A- and B-mediated actin cytoskeleton disruption. S.b is effective in preventing C. difficile infection by outbreak-associated via inhibition of the cytotoxic effects of C. difficile toxins.

Pro- and anti-inflammatory cytokine responses to a 164-km road cycle ride in a hot environment.

PURPOSE: The purpose of this study was to examine the circulating cytokine response to a recreational 164-km road cycling event in a high ambient temperature and to determine if this response was affected by self-paced exercise time to completion. METHODS: Thirty-five men and five women were divided into tertiles based on time to complete the cycling event: slowest (SLOW), moderate (MOD), and fastest (FAST) finishers. Plasma samples were obtained 1-2 h before (PRE) and immediately after (IP) the event. A high-sensitivity multiplex assay kit was used to determine the concentration of plasma anti-inflammatory cytokines (IL-4, IL-5, IL-10, IL-13) and pro-inflammatory cytokines (IL-1ß, IL-2, IL-6, IL-7, IL-8, IL-12, GM-CSF, IFN-γ, and TNF-α). RESULTS: The concentration of plasma IL-10 increased significantly (p < 0.05) in FAST and MOD groups and had no change in the SLOW group in response to a 164-km cycling event in the hot environment. Other cytokine responses were not influenced by the Time to completion. Pro-inflammatory cytokines IL-1ß, IL-2, GM-CSF, and TNF-α decreased; whereas, IL-6 and IL-8 increased from PRE to IP. Additionally, anti-inflammatory cytokines IL-4 and IL-13 decreased. CONCLUSIONS: Completion of a 164-km cycling event induced substantial changes in circulating pro- and anti-inflammatory cytokine concentrations. Time to completion appears to have a greater influence on the systemic IL-10 response than the environmental condition; however, it is possible that a threshold for absolute intensity must be reached for environmental conditions to affect the IL-10 response to exercise. Thus, cyclists from the FAST/MOD groups appear more likely to experience an acute transient immune suppression than cyclists from the SLOW group.

Physiological Effects of Nucleotide Supplementation on Resistance Exercise Stress in Men and Women.

Nucleotide supplementation can reduce postexercise immunosuppression and hypothalamic-pituitary axis (HPA) axis activation in endurance exercise models. Nucleotide supplementation may aid recovery from other exercise modalities, such as heavy resistance exercise. Thus, the purpose of this investigation was to investigate the effects of nucleotide supplementation on the acute cortisol and immune responses to heavy resistance exercise and its effects on recovery. A double-blinded, crossover, mixed methods design with 10 men and 10 women was used. Each performed an acute heavy resistance exercise protocol (AHREP) after a loading period with a nucleotide or placebo supplement. Before and after the AHREP, and at 24, 48, and 72 hours post, blood samples were analyzed for cortisol, myeloperoxidase (MPO), and absolute neutrophil, lymphocyte, and monocyte counts. Creatine kinase (CK) was analyzed before and 24, 48, and 72 hours after the AHREP. Performance measures, including peak back squat isometric force and peak countermovement jump power were also analyzed. Nucleotide supplementation resulted in significant (p ≤ 0.05) decreases in cortisol and MPO immediately after the AHREP, and significantly lower CK values 24 hours later. The AHREP significantly affected leukocyte counts; however, no treatment effects were observed. Greater isometric force was observed immediately after AHREP and at 24 hours and 48 hours with nucleotide supplementation. Nucleotide supplementation seems to attenuate muscle damage, HPA axis and immune system activation, and performance decrements after heavy resistance exercise.

Effect of cycling in the heat for 164 km on procoagulant and fibrinolytic parameters.

PURPOSE: We assessed the impact of completing the Hotter'n Hell Hundred (HHH), an annual 164 km road cycling event performed in a hot environment, on hemostatic balance in men. METHODS: Sixteen men who completed the ride in <6 h were included in this study. Plasma samples were collected on that morning of the ride (PRE) and immediately on the completion of the ride (IP). Primary hemostasis was assessed by platelet count and von Willebrand factor antigen (vWF:Ag). Coagulation was assessed by measuring prothrombin fragment 1 + 2 (PTF 1 + 2) and thrombin-antithrombin complex (TAT), whereas fibrinolysis was assessed by plasminogen activator inhibitor antigen (PAI-1 Ag), tissue plasminogen activator (tPA Ag), and D-Dimer analyses. RESULTS: Compared to PRE, increases (p < 0.001) were observed at IP for platelets (39 %), vWF:Ag (65 %), PTF 1 + 2 (47 %), TAT (81 %), tPA Ag (231 %), PAI-1 Ag (148 %), and D-Dimer (54 %). PRE PAI-1 Ag concentrations were directly related to BMI and waist circumference (p < 0.05). D-Dimer concentrations at IP correlated positively with age (p < 0.05). CONCLUSIONS: Completing the HHH activated the coagulation and fibrinolytic systems in balance. Age was positively correlated with IP D-Dimer concentrations. Additionally, participants displaying a larger BMI and waist circumference exhibited a positive correlation with PRE PAI-1 Ag concentrations.

Influence of HMB supplementation and resistance training on cytokine responses to resistance exercise.

PURPOSE: The purpose of this study was to determine the effects of a multinutritional supplement including amino acids, ß-hydroxy-ß-methylbutyrate (HMB), and carbohydrates on cytokine responses to resistance exercise and training. METHODS: Seventeen healthy, college-aged men were randomly assigned to a Muscle Armor™ (MA; Abbott Nutrition, Columbus, OH) or placebo supplement group and 12 weeks of resistance training. An acute resistance exercise protocol was administered at 0, 6, and 12 weeks of training. Venous blood samples at pre-, immediately post-, and 30-minutes postexercise were analyzed via bead multiplex immunoassay for 17 cytokines. RESULTS: After 12 weeks of training, the MA group exhibited decreased interferon-gamma (IFN-γ) and interleukin (IL)-10. IL-1ß differed by group at various times. Granulocyte colony-stimulating factor (G-CSF), granulocyte-macrophage colony-stimulating factor (GM-CSF), IL-6, IL-7, IL-8, IL-12p70, IL-13, IL-17, monocyte chemoattractant protein-1 (MCP-1), and macrophage inflammatory protein-1 beta (MIP-1ß) changed over the 12-week training period but did not differ by group. CONCLUSIONS: Twelve weeks of resistance training alters the cytokine response to acute resistance exercise, and supplementation with HMB and amino acids appears to further augment this result.

Repetitive box lifting performance is impaired in a hot environment: implications for altered work-rest cycles.

This study investigated the effects of environmental temperature on repetitive box lifting (RBL) performance, associated stress hormone and creatine kinase (CK) responses. Ten healthy males performed two experimental trials in a random crossover design. The trials consisted of three 40 min (10 min sitting, 20 min standing, and 10 min RBL) circuits performed in either 23 °C or 38 °C followed by a 180 min seated recovery period in 23 °C. RBL performance (i.e., number of boxes lifted) was reduced (p ≤ 0.05) in 38 °C compared to the 23 °C trial. Physiological Strain Index was significantly different between trials (38 °C: 8.5 ± 1.1 versus 23 °C: 7.2 ± 0.7; p ≤ 0.01). Plasma testosterone was elevated (p ≤ 0.05) across both trials and then decreased at 60 min recovery, compared to pre-exercise (PRE) measures, but was higher (p ≤ 0.05) during the 38 °C trial. Plasma cortisol increased (p ≤ 0.05) at 60 min during both trials and remained elevated until 120 min in 23 °C, and until 60 min recovery in 38 °C. Serum CK was greater through 48 hr post compared to PRE values in both trials. Thus, 10 min RBL performance was reduced in 38 °C despite the 30-min rest periods between RBL intervals. Plasma testosterone and cortisol were generally higher during the 38 °C trial, suggesting a greater stress response. Additional research is needed to determine optimal work:rest cycles for maximizing work performance in thermally oppressive environments.