Acute and Chronic Citrulline Malate Supplementation on Muscle Contractile Properties and Fatigue Rate of the Quadriceps.

This study compared the acute and chronic impact of citrulline malate (CM) supplementation on muscle contractile properties and fatigue rate of the quadriceps. Eighteen recreationally trained males consumed both a placebo (PL) and CM treatment for two separate dosing periods. The first experimental testing session for each dosing period was considered the baseline day, the second session the acute day, and the third session the chronic day, which followed seven consecutive days of supplementation. All testing sessions included exercising on a cycle ergometer at 50%-60% of their max power output for 30 min followed by performing the Thorstensson test on an isokinetic dynamometer. A two-way (Supplement × Time) analysis of variance with repeated measures resulted in no significant interactions (p > .05) (PL: baseline day, acute day, chronic day vs. CM: baseline day, acute day, chronic day) for peak power (in watts) (469 ± 81, 490 ± 97, 502 ± 99 vs. 464 ± 85, 480 ± 103, 501 ± 81); peak torque (in newton meters) (150 ± 26, 157 ± 32, 161 ± 31 vs. 149 ± 27, 156 ± 33, 161 ± 26); fatigue rate (in percentage) (57 ± 9, 57 ± 10, 58 ± 9 vs. 57 ± 10, 56 ± 9, 58 ± 9); and heart rate (in beats per minute) (156 ± 17, 146 ± 13, 146 ± 9 vs. 155 ± 11, 146 ± 11, 146 ± 9). The results of this study suggest that neither acute nor chronic supplementation of CM had an effect on recovery or fatigue rate of the quadriceps.

The Effect of Aspartate and Sodium Bicarbonate Supplementation on Muscle Contractile Properties Among Trained Men.

Farney, TM, MacLellan, MJ, Hearon, CM, Johannsen, NM, and Nelson, AG. The effect of aspartate and sodium bicarbonate supplementation on muscle contractile properties among trained men. J Strength Cond Res 34(3): 763-770, 2020-The focus of this investigation was to examine the effects of aspartate and NaHCO3 supplementation on muscle contractile properties within trained men. Eleven men (21.9 ± 1.5 years) ingested supplementation as 4 conditions all separated by 1 week and included the following: placebo (PLA), L-aspartate (12.5 mg) (ASP), NaHCO3 (0.3 g·kg) (SBC), or combination of ASP and SBC (CBO). For each day of testing, participants performed 1 high-intensity exercise session along with a pre- and postexercise (pre- or postex) isometric mid thigh pull test to measure peak force (PF) production and rate of force development (RFD). Blood was collected for all testing sessions before and after the high-intensity exercise to determine ammonia accumulation (AMM). Exercise sessions consisted of 4 exercises: barbell thrusters, squat jumps, lunge jumps, and forward jumps, with the total amount of work being equated for all 4 exercises across all 4 testing sessions. Participants performed the exercises in the aforementioned order, which was designated as 1 round. Each participant performed 3 rounds, with the work-to-rest ratio being 20-second work, 30-second rest. A 1-minute rest was given between the rounds. There were no treatment effects (p > 0.05) for PF, RFD, or AMM. However, there was a significant main effect for supplement consumption for the total time of work with the ASP, SBC, and CBO treatments having a lower time to completion compared with the PLA treatment. Ammonia was significantly elevated postexercise (p = 0.004), whereas there were no differences from preexercise to postexercise for PF or RFD (p > 0.05). The only significant treatment × time interaction was for RFD (p = 0.03) with CBO increasing postexercise, with the other 3 treatments all decreasing postexercise. The combination of ASP and SBC together may have the potential to reduce fatigue by mitigating the effects of metabolic by-product accumulation.

The Effect of Vinegar Supplementation on High-Intensity Cycling Performance within Recreationally Trained Individuals.

Background and objectives: To investigate the effects of vinegar ingestion upon high-intensity cycle performance in recreationally trained individuals. Materials and methods: Twenty-two participants consumed one of the following in a randomized order on four separate visits: (1) 29 mL of vinegar along with 451 mL of water, (2) 39 g of sucrose along with 441 mL of water, (3) 29 mL of vinegar and 39 g of sucrose along with 412 mL of water, or (4) 480 mL of water alone. For each of the experimental testing sessions, all participants completed in order: (1) high-intensity cycle test 1, (2) fatiguing cycle test, (3) high-intensity cycle test 2, (4) supplement consumption, (5) 90 min rest period, and (6) high-intensity cycle test 3. Total time to exhaustion (TTE) and average heart rate (HR) for each set of sprints was used in analysis. Results: There was no supplement by time interaction or significant main treatment effect observed (p > 0.05) for either TTE or HR. However, there was a main time effect observed, with TTE (p = 0.0001) being lower for cycle test 2 than both cycle test 1 and cycle test 3, and cycle test 3 being lower than cycle test 1. HR (p = 0.0001) was lower for cycle test 3 than both cycle test 1 and cycle test 2, but HR for cycle test 1 did not differ significantly from HR for cycle test 2. Conclusions: The addition of vinegar or sucrose alone, or in combination, was ineffective in improving cycle sprinting TTE when performing three cycle tests.

The Effect of Citrulline Malate Supplementation on Muscle Fatigue Among Healthy Participants.

Farney, TM, Bliss, MV, Hearon, CM, and Salazar, DA. The effect of citrulline malate supplementation on muscle fatigue among healthy participants. J Strength Cond Res 33(9): 2464-2470, 2019-The focus of the investigation was to examine the effects of citrulline malate (CM) on muscular fatigue in healthy, recreationally trained participants. Twelve participants (men = 6 and women = 6) (24.1 ± 3.9 years) visited the laboratory on 3 separate days, all separated by 1 week. Each visit consisted of consuming 1 of 3 treatments: placebo, CM (8 g), and control in which no drink mixture was consumed. For each day of testing, participants consumed assigned treatment and performed 1 high-intensity exercise trial consisting of squats, lunge jumps, squat jumps, and lateral jumps. Participants performed the exercises in the listed order, which was designated as 1 round. Each participant performed 3 rounds, with the work-to-rest ratio being 20 seconds of work and 30 seconds of rest. A 1-minute rest was given between rounds. A pre/post-exercise isokinetic leg extension test was performed to measure for peak power, peak torque, and rate of fatigue. In addition, blood lactate was obtained pre/post-exercise. There were no treatment or interaction effects (p > 0.05) for peak torque, peak power, rate of fatigue, or blood lactate accumulation. However, there was a statistical significant decrease from pre/post-exercise for peak torque (p = 0.003), peak power (p = 0.003), and rate of fatigue (p = 0.001). In addition, lactate accumulation did increase significantly from pre/post-exercise (p = 0.0001). Finally, neither total work nor final heart rate was statistically significant between the treatments (p > 0.05). Citrulline malate was not effective in improving performance or alleviating fatigue after a high-intensity exercise session.

Influence of acute exercise of varying intensity and duration on postprandial oxidative stress.

INTRODUCTION: Aerobic exercise can reduce postprandial lipemia, and possibly oxidative stress, when performed prior to a lipid-rich meal. PURPOSE: To compare the impact of acute exercise on postprandial oxidative stress. METHODS: We compared aerobic and anaerobic exercise bouts of different intensities and durations on postprandial blood triglycerides (TAG), oxidative stress biomarkers (malondialdehyde, hydrogen peroxide, advanced oxidation protein products), and antioxidant status (trolox equivalent antioxidant capacity, superoxide dismutase, catalase, glutathione peroxidase). Twelve trained men (21-35 years) underwent four conditions: (1) No exercise rest; (2) 60-min aerobic exercise at 70% heart rate reserve; (3) five 60-s sprints at 100% max capacity; and (4) ten 15-s sprints at 200% max capacity. All exercise bouts were performed on a cycle ergometer. A high-fat meal was consumed 1 h after exercise cessation. Blood samples were collected pre-meal and 2 and 4 h post-meal and analyzed for TAG, oxidative stress biomarkers, and antioxidant status. RESULTS: No significant interaction or condition effects were noted for any variable (p > 0.05), with acute exercise having little to no effect on the magnitude of postprandial oxidative stress. CONCLUSION: In a sample of healthy, well-trained men, neither aerobic nor anaerobic exercise attenuates postprandial oxidative stress in response to a high-fat meal.

Both a traditional and modified Daniel Fast improve the cardio-metabolic profile in men and women.

BACKGROUND: The Daniel Fast involves dietary modification similar to a purified vegan diet. Although improvements in several health-specific biomarkers have been noted with this plan, the removal of animal products results in a significant reduction in both dietary protein and saturated fatty acid intake, which results in a loss of lean body mass and a reduction in HDL-cholesterol. METHODS: We assigned 29 men and women to either a traditional or modified Daniel Fast for 21 days and measured anthropometric and biochemical markers of health pre and post intervention. The modified Daniel Fast was otherwise identical to the traditional plan but included one serving per day of lean meat and dairy (skim milk), providing approximately 30 grams per day of additional protein. RESULTS: Compared to baseline, both plans resulted in similar and significant improvements in blood lipids, as well as a reduction in inflammation. CONCLUSIONS: Modification of dietary intake in accordance with either a traditional or modified Daniel Fast may improve risk factors for cardiovascular and metabolic disease.

Acute plasma volume change with high-intensity sprint exercise.

When exercise is of long duration or of moderate to high intensity, a decrease in plasma volume can be observed. This has been noted for both aerobic and resistance exercise, but few data are available with regard to high-intensity sprint exercise. We measured plasma volume before and after 3 different bouts of acute exercise, of varying intensity, and/or duration. On different days, men (n = 12; 21-35 years) performed aerobic cycle exercise (60 minutes at 70% heart rate reserve) and 2 different bouts of cycle sprints (five 60-second sprints at 100% maximum wattage obtained during graded exercise testing (GXT) and ten 15-second sprints at 200% maximum wattage obtained during GXT). Blood was collected before and 0, 30, and 60 minutes postexercise and analyzed for hematocrit and hemoglobin and plasma volume was calculated. Plasma volume decreased significantly for all exercise bouts (p < 0.05), with the greatest decrease noted 0 minute postexercise for both sprint bouts (∼19%) compared with aerobic exercise bouts (∼11%). By 30 minutes postexercise, plasma volume approached pre-exercise values. We conclude that acute bouts of exercise, in particular high-intensity sprint exercise, significantly decrease plasma volume during the immediate postexercise period. It is unknown what, if any negative implications these transient changes may have on exercise performance. Strength and conditioning professionals may aim to rehydrate athletes appropriately after high-intensity exercise bouts.

Effect of grip width on electromyographic activity during the upright row.

The upright row (URR) is commonly used to develop the deltoid and upper back musculature. However, little information exists concerning muscle recruitment during variations of this exercise. Sixteen weight-trained men completed 2 repetitions each in the URR with 3 grip conditions: 50, 100, and 200% of the biacromial breadth (BAB). The load was the same for all grip conditions and was equal to 85% of the 1RM determined at 100% BAB. Repeated measures analyses of variance were used to compare the maximal activity of the anterior deltoid (AD), lateral deltoid (LD), posterior deltoid (PD), upper trapezius (UT), middle trapezius (MT), and biceps brachii (BB) during the 3 grip widths for eccentric and concentric actions. Significant differences (p < 0.05) were noted in concentric muscle activity for LD (p < 0.001) and PD (p < 0.001), and in eccentric muscle activity for AD (p = 0.023), LD (p < 0.001), UT (p < 0.001), MT (p < 0.001), and BB (p = 0.003). Bonferroni post hoc analysis revealed significant pairwise differences in the concentric actions from the LD (50% vs. 200% BAB and 100% vs. 200% BAB) and PD (50% vs. 200% BAB and 100% vs. 200% BAB), and eccentric actions of the LD (all comparisons), UT (all comparisons), MT (50% vs. 200% BAB and 100% vs. 200% BAB), and BB (50% vs. 200% BAB), with large-to-very-large effect sizes (ESs). Moderate-to-large ESs were noted for several nonsignificant comparisons. The main findings of this investigation are increased deltoid and trapezius activity with increasing grip width, and correspondingly less BB activity. Therefore, those who seek to maximize involvement of the deltoid and trapezius muscles during the URR should use a wide grip.

Cissus quadrangularis reduces joint pain in exercise-trained men: a pilot study.

BACKGROUND: Strenuous, high-volume exercise is often associated with inflammation and joint pain. Cissus quadrangularis (CQ) has been reported to have anti-inflammatory activity. The purpose of our study was to determine the therapeutic effects of CQ supplementation in healthy, exercise-trained men with joint-specific pain. METHODS: Twenty-nine men between the ages of 20 and 46 years, who reportedly experienced chronic joint pain as a result of strenuous exercise, participated in our pilot study. All men received CQ 3200 mg daily for 8 weeks. Before and after the 8-week intervention period, subjects completed a questionnaire to determine their degree of joint pain (Western Ontario and McMaster Universities Index of Osteoarthritis [WOMAC]). Clinical measures (eg, heart rate, blood pressure, blood biomarkers) were also collected for each subject pre- (baseline) and post-intervention. RESULTS: Subject ratings for multiple variables within the WOMAC Index improved (decreased) significantly (P < 0.05), with the subject mean total WOMAC score decreasing from 25.4 ± 2.4 to 17.4 ± 2.1 (~31%), pre- to post-intervention. No clinical measure was significantly impacted by use of CQ supplementation. CONCLUSION: An 8-week course of supplementation with CQ reduced joint pain in a sample of 29 young, otherwise healthy, exercise-trained men. Additional study is needed to extend these findings, including comparison with a placebo-controlled cohort, and possibly, examining effects of CQ use in women and older adult subjects.

Resistance Exercise Breaks Improve Ratings of Discomfort and Sleepiness in College Students.

Background: Emerging research suggests using resistance exercises to interrupt prolonged sitting may increase physical activity and reduce fatigue, sleepiness, and muscular discomfort, yet it is unclear if these improvements occur in college students. Methods: Twenty-four students (age 23.1 ± 3.4 years, BMI 27.4 ±  5.0 kg∙m-2) completed two 7-day assessments of discomfort, physical fatigue, mental fatigue, and sleepiness while wearing an ActivPAL. Each week (CON vs REX) followed normal activities while completing assessments in the morning (M), mid-day (MD), and evening (E). During REX, hourly resistance exercise breaks (1 exercise per break, 8 breaks per day) for 2 sets of 15 repetitions. Paired t-tests evaluated difference in physical activity variables. Repeated measures ANOVA (0 between, 3 within) evaluated differences in discomfort, physical fatigue, mental fatigue, and sleepiness variables across treatment (CON vs. REX). Results: Comparison of physical activity resulted in no statistical significance between treatments for all outcomes (p ≥ 0.05). A main effect for treatment was observed for overall discomfort (CON: 2.97, REX: 1.72; p = .042) and for sleepiness (CON: 4.38, REX: 3.89; p = .011). Conclusion: Hourly simple resistance breaks resulted in no compensation in steps or sedentary time while reducing muscular discomfort and sleepiness in a relatively healthy and active population.

The impact of the covid-19 pandemic on lifestyle behaviors in U.S. college students.

OBJECTIVE: To investigate COVID-19's impact on college student health behaviors. PARTICIPANTS: 189 college students. METHODS: Participants completed an online survey on behaviors relating to sleep, sedentary activities, and physical activity before and during the COVID-19 pandemic. Comparisons utilized Students' dependent t-test or Wilcoxon signed-rank tests. RESULTS: There was an increase in time to fall asleep (before: 23.4 ± 18.0 vs. during: 42.8 ± 44.3 min·day-1, p < 0.001), time spent in bed (before: 7.8 ± 1.5 vs. during: 8.5 ± 1.5 hr·day-1, p < 0.001), as well as shifts in later bed and awake time (p < 0.001). Total sedentary time increased during the pandemic (before: 9.0 ± 3.8 vs. during: 9.9 ± 4.1 hr·day-1, p = 0.016); and time spent using a TV, computer, or phone (before: 3.1 ± 1.9 vs. during: 4.2 ± 2.3 hr·day-1, p < 0.001). There was a significant decrease in moderate-vigorous activity (before: 123.8 ± 96.0 vs. during: 108.9 ± 75.5 min·week-1, p = 0.028) and resistance training days (before: 2.4 ± 2.1 vs. during: 1.7 ± 2.1 days·week-1, p < 0.001). CONCLUSIONS: COVID-19 negatively influenced health behaviors in college students.

Effects of 2-nitrooxy ethyl 2-amino 3-methylbutanoate gel on resistance exercise performance and blood nitrate/nitrite in resistance trained men.

Nitric oxide dietary supplements are popular within the sport community. Our recent work involving the oral intake of 2-nitrooxy ethyl 2-amino 3-methylbutanoate demonstrated an approximately 6.7% increase in circulating nitrate/nitrite. However, no measures of exercise performance were obtained. The present study used a topical form of this molecule to determine the impact on exercise performance and blood nitrate/nitrite. Fourteen resistance trained men (24 ± 1 years old) reported to the laboratory on 2 occasions to undergo exercise testing, which consisted of arm curl isometric force and muscular endurance (3 sets to fatigue using 80, 65, and 50% of 1 repetition maximum [1RM]: total of 9 sets). The gel (2-nitrooxy ethyl 2-amino 3-methylbutanoate; mixed in tea tree oil) or placebo (tea tree oil) was applied topically by the subjects for 7 days before each test day, with 7-10 days separating the randomly ordered conditions. Blood samples, arm circumference, and perceived "muscle pump" were taken before and immediately after exercise on both test days. The heart rate and perceived exertion were measured after each set. No statistically significant differences were noted between conditions for performance variables (p > 0.05). However, when using a load of 50% of 1RM, 6.2% more repetitions were performed when using the gel as compared with when using the placebo; 19.9% more repetitions were performed by 8 subjects noted to be "responders" to gel treatment. Blood lactate and muscle pump significantly increased with exercise (p < 0.0001) but were not different between conditions (p > 0.05). Minimal change was noted in nitrate/nitrite, and the heart rate and perceived exertion were nearly identical between conditions (p > 0.05). These findings indicate that 2-nitrooxy ethyl 2-amino 3-methylbutanoate gel has a modest (6.2%), nonstatistically significant effect on exercise performance, in particular when using a load of 50% 1RM-with greater benefit noted in selected individuals. Studies inclusive of a larger sample size are needed to extend these initial findings.

The effects of chronic betaine supplementation on exercise performance, skeletal muscle oxygen saturation and associated biochemical parameters in resistance trained men.

Trepanowski, JF, Farney, TM, McCarthy, CG, Schilling, BK, Craig, SA, and Bloomer, RJ. The effects of chronic betaine supplementation on exercise performance, skeletal muscle oxygen saturation, and associated biochemical parameters in resistance trained men. J Strength Cond Res 25(12): 3461-3471, 2011-We examined the effects of chronic betaine supplementation on exercise performance and associated parameters in resistance trained men. Men were randomly assigned in a double-blind manner using a crossover design to consume betaine (2.5 g of betaine mixed in 500 ml of Gatorade®) or a placebo (500 ml of Gatorade®) for 14 days, with a 21-day washout period. Before and after each treatment period, tests of lower- and upper-body muscular power and isometric force were conducted, including a test of upper-body muscular endurance (10 sets of bench press exercise to failure). Muscle tissue oxygen saturation (StO2) during the bench press protocol was measured via near infrared spectroscopy. Blood samples were collected before and after the exercise test protocol for analysis of lactate, nitrate/nitrite (NOx), and malondialdehyde (MDA). When analyzed using a repeated measures analysis of variance, no significant differences were noted between conditions for exercise performance variables (p > 0.05). However, an increase in total repetitions (p = 0.01) and total volume load (p = 0.02) in the 10-set bench press protocol was noted with betaine supplementation (paired t-tests), with values increasing approximately 6.5% from preintervention to postintervention. Although not of statistical significance (p = 0.14), postexercise blood lactate increased to a lesser extent with betaine supplementation (210%) compared with placebo administration (270%). NOx was lower postintervention as compared with preintervention (p = 0.06), and MDA was relatively unchanged. The decrease in StO2 during the bench press protocol was greater with betaine vs. placebo (p = 0.01), possibly suggesting enhanced muscle oxygen consumption. These findings indicate that betaine supplementation results in a moderate increase in total repetitions and volume load in the bench press exercise, without favorably impacting other performance measures.

Effects of 1,3-dimethylamylamine and caffeine alone or in combination on heart rate and blood pressure in healthy men and women.

BACKGROUND: The use of 1,3-dimethylamylamine (geranamine), alone and in combination with caffeine, is becoming widespread within the dietary supplement industry. To our knowledge, no data are available concerning the effects of oral geranamine intake on heart rate (HR) and blood pressure in individuals. METHODS: Ten young healthy men and women ingested 1 of 5 conditions on different days using a double-blind, randomized, crossover design. The following were ingested after a 10-hour overnight fast: 250 mg caffeine (C), 50 mg geranamine (G 50 mg), 75 mg geranamine (G 75 mg), 250 mg caffeine + 50 mg geranamine (C + G 50 mg), and 250 mg caffeine + 75 mg geranamine (C + G 75 mg). Heart rate, systolic blood pressure (SBP), diastolic blood pressure (DBP), and rate pressure product (RPP) were measured pre-ingestion and at 30, 60, 90, and 120 minutes post-ingestion. Plasma norepinephrine (NE) and epinephrine (EPI) were measured pre-ingestion and at 60 and 120 minutes post-ingestion. RESULTS: Heart rate was unaffected by treatment, but blood pressure and RPP were higher with geranamine, generally in a dose-dependent manner. The peak percent change from pre-ingestion in SBP (~20%), DBP (~17%), and RPP (~9%) was noted with C + G 75 mg at 60 minutes post-ingestion. Plasma NE and EPI were relatively unaffected by treatment. CONCLUSION: We report for the first time that acute ingestion of 1,3-dimethylamylamine alone and in combination with caffeine results in an increase in SBP, DBP, and RPP without an increase in HR. The largest increase is observed at 60 minutes post-ingestion of C + G 75 mg. These changes cannot be explained by circulating NE and EPI.

Postprandial oxidative stress in response to dextrose and lipid meals of differing size.

UNLABELLED: We have recently noted that ingestion of dietary lipid (in the form of heavy whipping cream) leads to greater oxidative stress than dietary carbohydrate (in the form of dextrose), when consumed in isocaloric amounts. OBJECTIVE: In the present investigation we attempted to replicate our work and also to determine the oxidative stress response to dextrose and lipid meals of two different kilocalorie (kcal) amounts. DESIGN: Nine young (22 +/- 2 years), healthy men consumed in a random order, cross-over design one of four meals/drinks: dextrose at 75 g (300 kcals), dextrose at 150 g (600 kcals), lipid at 33 g (300 kcals), lipid at 66 g (600 kcals). Blood samples were collected Pre meal, and at 30 min, 60 min, 120 min, and 180 min post meal. Samples were assayed for glucose, triglycerides (TAG), malondialdehyde (MDA), and hydrogen peroxide (H2O2). Area under the curve (AUC) was calculated for each variable, and a 4 x 5 ANOVA was utilized to further analyze data. RESULTS: A meal x time effect (p = 0.0002) and a time effect was noted for glucose (p < 0.0001; 30 min > Pre, 1 hr, 2 hr, and 3 hr). The dextrose meals primarily contributed to this time effect. No other effects were noted for glucose (p > 0.05). A meal effect was noted for TAG (p = 0.01; 66 g lipid meal > 75 g and 150 g dextrose meals). No other effects were noted for TAG (p > 0.05). An AUC effect was noted for MDA (p = 0.04; 66 g lipid meal > 75 g and 150 g dextrose meals). A meal x time effect (p = 0.02) and a meal effect was noted for MDA (p = 0.004; 66 g lipid meal > 75 g and 150 g dextrose meals). No time effect was noted for MDA (p = 0.72). An AUC effect was noted for H2O2 (p = 0.0001; 66 g lipid meal > 33 g lipid meal and 75 g and 150 g dextrose meals). A meal x time effect (p = 0.0002), a meal effect (p < 0.0001; 66 g lipid meal > 33 g lipid meal and 75 g and 150 g dextrose meals), and a time effect was noted for H2O2 (p < 0.0001; 2 hr > Pre, 30 min, and 1 hr; 3 hr > Pre). The time effect for H2O2 was primarily influenced by the 66 g lipid meal. CONCLUSIONS: These data indicate that 1) minimal oxidative stress is observed following ingestion of dextrose loads of either 75 g or 150 g, or a lipid load of 33 g and 2) lipid ingestion at 66 g leads to greater oxidative stress than lipid at 33 g or dextrose at either 75 g or 150 g. Hence, in a sample of young and healthy men, only 66 g of lipid (taken in the form of heavy whipping cream) leads to a significant increase in blood oxidative stress, as measured by MDA and H2O2.

Effect of a 21 day Daniel Fast on metabolic and cardiovascular disease risk factors in men and women.

BACKGROUND: Dietary modification via caloric restriction is associated with multiple effects related to improved metabolic and cardiovascular health. However, a mandated reduction in kilocalories is not well-tolerated by many individuals, limiting the long-term application of such a plan. The Daniel Fast is a widely utilized fast based on the Biblical book of Daniel. It involves a 21 day ad libitum food intake period, devoid of animal products and preservatives, and inclusive of fruits, vegetables, whole grains, legumes, nuts, and seeds. The purpose of the present study was to determine the efficacy of the Daniel Fast to improve markers of metabolic and cardiovascular disease risk. METHODS: 43 subjects (13 men; 30 women; 35 ± 1 yrs; range: 20-62 yrs) completed a 21 day period of modified food intake in accordance with detailed guidelines provided by investigators. All subjects purchased and prepared their own food. Following initial screening, subjects were given one week to prepare for the fast, after which time they reported to the lab for their pre-intervention assessment (day 1). After the 21 day fast, subjects reported to the lab for their post-intervention assessment (day 22). For both visits, subjects reported in a 12 hr fasted state, performing no strenuous physical activity during the preceding 24-48 hrs. At each visit, mental and physical health (SF-12 form), resting heart rate and blood pressure, and anthropometric variables were measured. Blood was collected for determination of complete blood count, metabolic panel, lipid panel, insulin, HOMA-IR, and C-reactive protein (CRP). Subjects' self-reported compliance, mood, and satiety in relation to the fast were also recorded. Diet records were maintained by all subjects during the 7 day period immediately prior to the fast (usual intake) and during the final 7 days of the fast. RESULTS: Subjects' compliance to the fast was 98.7 ± 0.2% (mean ± SEM). Using a 10 point scale, subjects' mood and satiety were both 7.9 ± 0.2. The following variables were significantly (p < 0.05) lower following the fast as compared to before the fast: white blood cell count (5.68 ± 0.24 vs. 4.99 ± 0.19 103.µL-1), blood urea nitrogen (13.07 ± 0.58 vs. 10.14 ± 0.59 mg.dL-1), blood urea nitrogen/creatinine (14.74 ± 0.59 vs. 11.67 ± 0.68), protein (6.95 ± 0.07 vs. 6.77 ± 0.06 g.dL-1), total cholesterol (171.07 ± 4.57 vs. 138.69 ± 4.39 mg.dL-1), LDL-C (98.38 ± 3.89 vs. 76.07 ± 3.53 mg.dL-1), HDL-C (55.65 ± 2.50 vs. 47.58 ± 2.19 mg.dL-1), SBP (114.65 ± 2.34 vs. 105.93 ± 2.12 mmHg), and DBP (72.23 ± 1.59 vs. 67.00 ± 1.43 mmHg). Insulin (4.42 ± 0.52 vs. 3.37 ± 0.35 µU.mL-1; p = 0.10), HOMA-IR (0.97 ± 0.13 vs.0.72 ± 0.08; p = 0.10), and CRP (3.15 ± 0.91 vs. 1.60 ± 0.42 mg.L-1; p = 0.13), were lowered to a clinically meaningful, albeit statistically insignificant extent. No significant difference was noted for any anthropometric variable (p > 0.05). As expected, multiple differences in dietary intake were noted (p < 0.05), including a reduction in total kilocalorie intake (2185 ± 94 vs. 1722 ± 85). CONCLUSION: A 21 day period of modified dietary intake in accordance with the Daniel Fast is 1) well-tolerated by men and women and 2) improves several risk factors for metabolic and cardiovascular disease. Larger scale, randomized studies, inclusive of a longer time period and possibly a slight modification in food choice in an attempt to maintain HDL cholesterol, are needed to extend these findings.

Acute effect of nitric oxide supplement on blood nitrate/nitrite and hemodynamic variables in resistance trained men.

Nitric oxide dietary supplements are extremely popular within the sport and bodybuilding community. Most products contain l-arginine, for which there is no direct evidence that oral L-arginine increases circulating nitric oxide or blood flow. A new molecule (2-[nitrooxy]thyl 2-amino-3-methylbutanoate) is being marketed as a sport supplement for purposes of delivering "real nitric oxide" to the circulation. In the present study, we measured the acute effects of this supplement on blood nitrate/nitrite and hemodynamic variables. Ten resistance trained men (26 ± 4 years old; 8 ± 6 years of resistance exercise training) reported to the laboratory in random order after a 10-hour overnight fast on 2 occasions separated by 1 week and were provided the supplement (2-[nitrooxy]ethyl 2-amino-3-methylbutanoate) or placebo. Heart rate and blood pressure were recorded, and venous blood samples were collected before and at 5, 15, 30, and 60 minutes after complete breakdown of the supplement (5 minutes post intake) or placebo. Blood samples were assayed for plasma nitrate/nitrite. No interaction (p = 0.99), condition (p = 0.18), or time (p = 0.98) effects were noted for plasma nitrate/nitrite, with values remaining nearly identical across time for placebo (∼27 µmol·L(-1)) and increasing a maximum of ∼6.7% (from 32.9 to 35.1 µmol·L(-1)) at the 15-minute collection period for the supplement. In regards to hemodynamic variables, no interaction, condition, or time effects were noted for heart rate, systolic, or diastolic blood pressure (p > 0.05), with values near identical between conditions and virtually unchanged across time. These findings indicate that 2-(nitrooxy)ethyl 2-amino-3-methylbutanoate has a small effect on increasing circulating nitrate/nitrite and does not cause any change in hemodynamic variables within the 1 hour postingestion period in a sample of resistance trained men.

Muscle Sentry® has No Effect on Total Work Performed and Estimated MVO 2 after High Intensity Short Duration Resistance Training.

Supplements are widely used in recreational and professional participants; however, their claimed benefits are hardly to test. This study compared the total lifted numbers and post-exercise estimated MVO2 while subjects were treated with either Muscle Sentry® (MS) or placebo (PL), in a 7-day washout period. Participants (11 women, 10 men, 20-24 years) performed 3 sets to failure chest and leg press exercises at 8 RM with 2 min rest between sets. Each exercise was performed four times (2 × MS, 2 × PL) at the same time of the day separated by 48 h. The supplementation was ingested 40 min prior to perform the exercise. Prior to the exercise and immediately after each set, both HR and BP were obtained. The rate pressure product (RPP) was then calculated to determine estimated MVO2. Daily RPP and total weight lifted (chest + leg) for each supplementation were averaged. Normalized RPP was the ratio of averaged RPP and averaged total weight lifted. No treatment effect on chest, leg and total lift numbers, normalized post RPP (NPRPP), normalized RPPdiff (NRPPdiff) (p=0.94, 0.86, 0.87, 0.87, 0.43 respectively); No treatment effect on total lift numbers, NPRPP, NRPPdiff for gender (p=0.87, 0.95, 0.96 respectively). Ingestion of Muscle Sentry® 40 min prior to do 3 sets to failure of both chest and leg presses had no effect upon either total lift numbers or estimated MVO2. This suggests that, in some instances, the benefits of Muscle Sentry® are less than those claimed by the manufacturer.

Caffeine, acute static stretching and maximum knee flexion strength.

BACKGROUND: Reductions in one-repetition maximum lifts (1RM) following static stretching can be attributed to enhanced neural inhibition, which can be reduced by using stimulants like caffeine. This study compared knee-flexion 1RM following either static stretching (SS) or no-stretching (NS), as well as after ingesting either caffeine (C) or placebo (P). METHODS: Twenty-four participants (12 female, 12 male) performed four random counterbalanced knee flexion 1RM tests. A 1RM test was performed for each condition at the same time of day with ~48 hours separating each test. Static stretching consisted of 5 exercises with the 1RM being performed immediately following the stretching. Caffeine dose was 6 mg/kg body weight, and the placebo was methylcellulose (520 mg). Both doses were administered as pills 60 minutes before the SS or NS procedures. RESULTS: Two-way repeated measures ANOVA showed a significant main effect for NS vs. SS (P<0.001, ηG2=0.23). The main effect for C vs. P, and the interaction between C vs. P and NS vs. SS were not statistically different. Average 1RMs were: CNS = 512±242 N, CSS = 474±241 N, PNS = 498±247 N, and PSS = 460±247 N. CONCLUSIONS: It is concluded that static stretching induced strength decrements are not removed by using stimulants at doses allowed by sport governing organizations.

A Pre-Exercise Dose of Muscle Sentry® has no Effect on Performing Repeated Leg Press Sets to Failure.

This study compared the number of bilateral leg presses done at 150% of body mass while on either Muscle Sentry® (MS) or placebo (PL). Participants (16 women, 14 men, college students 19-26 years) performed 2 sets of leg press to failure using 150% of their body mass with 5 min rest separating the 2 sets. Each exercise was performed twice (1× MS, 1× PL) at the same time of day with 48 h separating each exercise. Both MS and PL were ingested 30 min prior to performing the exercise. Just prior to starting the exercise and at the end of each set, heart rate, and blood pressure were obtained and the rate pressure product was calculated to determine myocardial workload. Two-way repeated measures ANOVA for lift number showed no significant main effects for either MS vs. PL, or for Set1 vs. Set2 (p > 0.05). The interaction was also not statistically different (mean repetitions ± std. dev.: MS1= 28±20, MS2= 26±18, PL1 = 30±24, PL2 = 29±20). Two-way repeated measures ANOVA for rate pressure product showed no significance for either the main effect for MS vs. PL, or supplement × pre-post interaction (p > 0.05). The main effect for pre-lift vs. post lift was significant (p<0.001) with post being higher than pre. Ingestion of Muscle Sentry® 30 min prior to leg pressing 150% of body mass to failure had no effect upon either total work performance or myocardial workload.