This study examined 12 wk of resistance training and cystoseim canariensis supplementation on serum levels of myostatin and follistatin-like related gene (FLRG) and muscle strength and body composition. Twenty-two untrained males were randomly assigned to a placebo (PLC) or myostatin binder (MYO) group in a double-blind fashion. Blood was obtained before and after 6 and 12 wk of training. PLC and MYO trained thrice weekly using 3 sets of 6 to 8 repetitions at 85% to 90% 1 repetition maximum. MYO ingested 1200 mg/d of cystoseim canariensis. Data were analyzed with 2-way ANOVA. After training, total body mass, fat-free mass, muscle strength, thigh volume/mass, and serum myostatin and FLRG increased for both groups (P < 0.05); however, there were no differences between groups (P > 0.05). Twelve wk of heavy resistance training and 1200 mg/d of cystoseim canariensis supplementation appears ineffective at inhibiting serum myostatin and increasing muscle strength and mass or decreasing fat mass.
Ahmed Ismaeel, Suzy Weems and Darryn S. Willoughby
The purpose of this study was to provide a descriptive assessment of the nutritional habits of competitive bodybuilders and compare the nutrient intakes of macronutrient-based dieting and strict dieting individuals. Data from 41 subjects (30 males and 11 females) were used in analyses. Participants completed a comprehensive food frequency questionnaire, and diets were analyzed using a computer system. Males consumed an average of 2,577.2 kcal (SD = 955.1), with an average fat intake of 83.6 g (SD = 41.3), an average carbohydrate intake of 323.3 g (SD = 105.2), and an average protein intake of 163.4 g (SD = 70.4). There were no significant differences between male macronutrient-based dieting and strict dieting bodybuilders when mean intakes were compared for all nutrients, including the macronutrients, selected vitamins and minerals, dietary fiber, added sugars, and saturated fat. Females in this study consumed an average of 1,794 kcal (SD = 453.1), with an average fat intake of 58.3 g (SD = 23.1), a mean carbohydrate intake of 217.8 g (SD = 85.9), and an average protein intake of 103.8 g (SD = 35.7). For females, macronutrient-based dieters consumed significantly greater amounts of several nutrients, including protein, vitamin E, vitamin K, and vitamin C. Over half of individuals from all groups consumed less than the recommended amounts of several of the micronutrients. Based on this information, it is recommended that competitive bodybuilders should be advised to take their micronutrition into greater consideration.
Grant M. Tinsley and Darryn S. Willoughby
Low-carbohydrate and very-low-carbohydrate diets are often used as weight-loss strategies by exercising individuals and athletes. Very-low-carbohydrate diets can lead to a state of ketosis, in which the concentration of blood ketones (acetoacetate, 3-β-hydroxybutyrate, and acetone) increases as a result of increased fatty acid breakdown and activity of ketogenic enzymes. A potential concern of these ketogenic diets, as with other weight-loss diets, is the potential loss of fat-free mass (e.g., skeletal muscle). On examination of the literature, the majority of studies report decreases in fat-free mass in individuals following a ketogenic diet. However, some confounding factors exist, such as the use of aggressive weight-loss diets and potential concerns with fat-free mass measurement. A limited number of studies have examined combining resistance training with ketogenic diets, and further research is needed to determine whether resistance training can effectively slow or stop the loss of fat-free mass typically seen in individuals following a ketogenic diet. Mechanisms underlying the effects of a ketogenic diet on fat-free mass and the results of implementing exercise interventions in combination with this diet should also be examined.
Darryn S. Willoughby, Colin Wilborn, Lemuel Taylor and William Campbell
This study examined the effects of an aromatase-inhibiting nutritional supplement on serum steroid hormones, body composition, and clinical safety markers. Sixteen eugonadal young men ingested either Novedex XT™ or a placebo daily for 8 wk, followed by a 3-wk washout period. Body composition was assessed and blood and urine samples obtained at weeks 0, 4, 8, and 11. Data were analyzed by 2-way repeated-measures ANOVA. Novedex XT resulted in average increases of 283%, 625%, 566%, and 438% for total testosterone (P = 0.001), free testosterone (P = 0.001), dihydrotestosterone (P = 0.001), and the testosterone:estrogen ratio (P = 0.001), respectively, whereas fat mass decreased 3.5% (P = 0.026) during supplementation. No significant differences were observed in blood and urinary clinical safety markers or for any of the other serum hormones (P > 0.05). This study indicates that Novedex XT significantly increases serum androgen levels and decreases fat mass.
Darryn S. Willoughby, Tony Boucher, Jeremy Reid, Garson Skelton and Mandy Clark
Arginine-alpha-ketoglutarate (AAKG) supplements are alleged to increase nitric oxide production, thereby resulting in vasodilation during resistance exercise. This study sought to determine the effects of AAKG supplementation on hemodynamics and brachial-artery blood flow and the circulating levels of L-arginine, nitric oxide metabolites (NOx; nitrate/nitrite), asymmetric dimethyl arginine (ADMA), and L-arginine:ADMA ratio after resistance exercise.
Twenty-four physically active men underwent 7 days of AAKG supplementation with 12 g/day of either NO2 Platinum or placebo (PLC). Before and after supplementation, a resistance-exercise session involving the elbow flexors was performed involving 3 sets of 15 repetitions with 70–75% of 1-repetition maximum. Data were collected immediately before, immediately after (PST), and 30 min after (30PST) each exercise session. Data were analyzed with factorial ANOVA (p < .05).
Heart rate, blood pressure, and blood flow were increased in both groups at PST (p = .001) but not different between groups. Plasma L-arginine was increased in the NO2 group (p = .001). NOx was shown to increase in both groups at PST (p = .001) and at 30PST (p = .001) but was not different between groups. ADMA was not affected between tests (p = .26) or time points (p = .31); however, the L-arginine:ADMA ratio was increased in the NO2 group (p = .03).
NO2 Platinum increased plasma L-arginine levels; however, the effects observed in hemodynamics, brachial-artery blood flow, and NOx can only be attributed to the resistance exercise.