Effects of nine weeks L-Carnitine supplementation on exercise performance, anaerobic power, and exercise-induced oxidative stress in resistance-trained males.

PURPOSE: Studies of L-carnitine in healthy athletic populations have yielded equivocal results. Further scientific-based knowledge is needed to clarify the ability of L-carnitine to improve exercise capacity and expedite the recovery process by reducing oxidative stress. This study aimed to examine the 9-week effects of L-carnitine supplementation on exercise performance, anaerobic capacity, and exercise-induced oxidative stress markers in resistance-trained males. METHODS: In a double-blind, randomized, and placebo-controlled treatment, 23 men (age, 25±2y; weight, 81.2±8.31 kg; body fat, 17.1±5.9%) ingested either a placebo (2 g/d, n=11) or L-carnitine (2 g/d, n=12) for 9 weeks in conjunction with resistance training. Primary outcome measurements were analyzed at baseline and at weeks 3, 6, and 9. Participants underwent a similar resistance training (4 d/w, upper/lower body split) for a 9-week period. Two-way ANOVA with repeated measures was used for statistical analysis. RESULTS: There were significant increases in bench press lifting volume at wk-6 (146 kg, 95% CI 21.1, 272) and wk-9 (245 kg, 95% CI 127, 362) with L-carnitine. A similar trend was observed for leg press. In the L-carnitine group, at wk-9, there were significant increases in mean power (63.4 W, 95% CI 32.0, 94.8) and peak power (239 W, 95% CI 86.6, 392), reduction in post-exercise blood lactate levels (-1.60 mmol/L, 95% CI -2.44, -0.75) and beneficial changes in total antioxidant capacity (0.18 mmol/L, 95% CI 0.07, 0.28). CONCLUSION: L-carnitine supplementation enhances exercise performance while attenuating blood lactate and oxidative stress responses to resistance training.

Effects of ingesting a pre-workout dietary supplement with and without synephrine for 8 weeks on training adaptations in resistance-trained males.

BACKGROUND: The purpose of this study was to examine whether ingesting a pre-workout dietary supplement (PWS) with and without synephrine (S) during training affects training responses in resistance-trained males. METHODS: Resistance-trained males (N = 80) were randomly assigned to supplement their diet in a double-blind manner with either a flavored placebo (PLA); a PWS containing beta-alanine (3 g), creatine nitrate as a salt (2 g), arginine alpha-ketoglutarate (2 g), N-Acetyl-L-Tyrosine (300 mg), caffeine (284 mg), Mucuna pruiriens extract standardized for 15% L-Dopa (15 mg), Vitamin C as Ascorbic Acid (500 mg), niacin (60 mg), folate as folic acid (50 mg), and Vitamin B12 as Methylcobalamin (70 mg); or, the PWS supplement with Citrus aurantium extract containing 20 mg of synephrine (PWS + S) once per day for 8-weeks during training. Participants donated a fasting blood sample and had body composition (DXA), resting heart rate and blood pressure, cognitive function (Stroop Test), readiness to perform, bench and leg press 1 RM, and Wingate anaerobic capacity assessments determined a 0, 4, and 8-weeks of standardized training. Data were analyzed by MANOVA with repeated measures. Performance and cognitive function data were analyzed using baseline values as covariates as well as mean changes from baseline with 95% confidence intervals (CI). Blood chemistry data were also analyzed using Chi-square analysis. RESULTS: Although significant time effects were seen, no statistically significant overall MANOVA Wilks' Lambda interactions were observed among groups for body composition, resting heart and blood pressure, readiness to perform questions, 1RM strength, anaerobic sprint capacity, or blood chemistry panels. MANOVA univariate analysis and analysis of changes from baseline with 95% CI revealed some evidence that cognitive function and 1RM strength were increased to a greater degree in the PWS and/or PWS + S groups after 4- and/or 8-weeks compared to PLA responses. However, there was no evidence that PWS + S promoted greater overall training adaptations compared to the PWS group. Dietary supplementation of PWS and PWS + S did not increase the incidence of reported side effects or significantly affect the number of blood values above clinical norms compared to PLA. CONCLUSION: Results provide some evidence that 4-weeks of PWS and/or PWS + S supplementation can improve some indices of cognitive function and exercise performance during resistance-training without significant side effects in apparently health males. However, these effects were similar to PLA responses after 8-weeks of supplementation and inclusion of synephrine did not promote additive benefits. TRIAL REGISTRATION: This trial (NCT02999581) was retrospectively registered on December 16th 2016.

Effects of acute ingestion of a pre-workout dietary supplement with and without p-synephrine on resting energy expenditure, cognitive function and exercise performance.

BACKGROUND: The purpose of this study was to examine the effects of acute ingestion of a pre-workout dietary supplement (PWS) with and without p-synephrine (S) on perceptions of readiness to perform, cognitive function, exercise performance, and markers of safety. METHODS: In a randomized, double-blind, and counterbalanced manner; 25 healthy and recreationally active male and female participants ingested a flavored maltodextrin placebo (PLA), a PWS containing beta-alanine (3 g), creatine nitrate as a salt (2 g), arginine alpha-ketoglutarate (2 g), N-Acetyl-L-Tyrosine (300 mg), caffeine (284 mg), Mucuna pruiriens extract standardized for 15% L-Dopa (15 mg), Vitamin C as Ascorbic Acid (500 mg), niacin (60 mg), folate as folic acid (50 mg), and Vitamin B12 as Methylcobalamin (70 mg) with 2 g of maltodextrin and flavoring; or, the PWS with Citrus aurantium (PWS + S) extract standardized for 30% p-synephrine (20 mg). Participants had heart rate (HR), blood pressure, resting energy expenditure (REE), 12-lead electrocardiograms (ECG), perceptions about readiness to perform, cognitive function (Stroop Color-Word test), bench and leg press performance (2 sets of 10 repetitions at 70% of 1RM and 1 set to failure), and Wingate anaerobic capacity (WAC) sprint performance determined as well as donated blood samples prior to and/or following exercise/supplementation. Data were analyzed by MANOVA with repeated measures as well as mean changes from baseline with 95% confidence intervals (CI). RESULTS: No clinically significant differences were observed among treatments in HR, blood pressure, ECG, or general clinical blood panels. There was evidence that PWS and PWS + S ingestion promoted greater changes in REE responses. Participants reported higher perception of optimism about performance and vigor and energy with PWS and PWS + S ingestion and there was evidence that PWS and PWS + S improved changes in cognitive function scores from baseline to a greater degree than PLA after 1 or 2 h. However, the scores in the PWS + S treatment did not exceed PLA or PWS responses at any data point. No statistically significant differences were observed among treatments in total bench press lifting volume, leg press lifting volume or WAC sprint performance. CONCLUSIONS: Within the confines of this study, ingestion of PWS and/or PWS + S prior to exercise appears to be well-tolerated when consumed by young, healthy individuals. The primary effects appear to be to increase REE responses and improve perceptions about readiness to perform and cognitive function with limited to no effects on muscular endurance and WAC. The addition of 20 mg of p-synephrine to the PWS provided limited to no additive benefits. TRIAL REGISTRATION: This trial (NCT02952014) was retrospectively registered on September 13th 2016.

Efficacy of a randomized trial examining commercial weight loss programs and exercise on metabolic syndrome in overweight and obese women.

While commercial dietary weight-loss programs typically advise exercise, few provide actual programing. The goal of this study was to compare the Curves Complete 90-day Challenge (CC, n = 29), which incorporates exercising and diet, to programs advocating exercise (Weight Watchers Points Plus (WW, n = 29), Jenny Craig At Home (JC, n = 27), and Nutrisystem Advance Select (NS, n = 28)) or control (n = 20) on metabolic syndrome (MetS) and weight loss. We randomized 133 sedentary, overweight women (age, 47 ± 11 years; body mass, 86 ± 14 kg; body mass index, 35 ± 6 kg/m2) into respective treatment groups for 12 weeks. Data were analyzed using chi square and general linear models adjusted for age and respective baseline measures. Data are means ± SD or mean change ± 95% confidence intervals (CIs). We observed a significant trend for a reduction in energy intake for all treatment groups and significant weight loss for all groups except control: CC (-4.32 kg; 95% CI, -5.75, -2.88), WW (-4.31 kg; 95% CI, -5.82, -2.96), JC (-5.34 kg; 95% CI, -6.86, -3.90), NS (-5.03 kg; 95% CI, -6.49, -3.56), and control (0.16 kg, 95% CI, -1.56, 1.89). Reduced MetS prevalence was observed at follow-up for CC (35% vs. 14%, adjusted standardized residuals (adjres.) = 3.1), but not WW (31% vs. 28% adjres. = 0.5), JC (37% vs. 42%, adjres. = -0.7), NS (39% vs. 50% adjres. = -1.5), or control (45% vs. 55% adjres. = -1.7). While all groups improved relative fitness (mL·kg-1·min-1) because of weight loss, only the CC group improved absolute fitness (L/min). In conclusion, commercial programs offering concurrent diet and exercise programming appear to offer greater improvements in MetS prevalence and cardiovascular function after 12 weeks of intervention.