Protein timing and its effects on muscular hypertrophy and strength in individuals engaged in weight-training.

The purpose of this review was to determine whether past research provides conclusive evidence about the effects of type and timing of ingestion of specific sources of protein by those engaged in resistance weight training. Two essential, nutrition-related, tenets need to be followed by weightlifters to maximize muscle hypertrophy: the consumption of 1.2-2.0 g protein.kg -1 of body weight, and ≥44-50 kcal.kg-1 of body weight. Researchers have tested the effects of timing of protein supplement ingestion on various physical changes in weightlifters. In general, protein supplementation pre- and post-workout increases physical performance, training session recovery, lean body mass, muscle hypertrophy, and strength. Specific gains, differ however based on protein type and amounts. Studies on timing of consumption of milk have indicated that fat-free milk post-workout was effective in promoting increases in lean body mass, strength, muscle hypertrophy and decreases in body fat. The leucine content of a protein source has an impact on protein synthesis, and affects muscle hypertrophy. Consumption of 3-4 g of leucine is needed to promote maximum protein synthesis. An ideal supplement following resistance exercise should contain whey protein that provides at least 3 g of leucine per serving. A combination of a fast-acting carbohydrate source such as maltodextrin or glucose should be consumed with the protein source, as leucine cannot modulate protein synthesis as effectively without the presence of insulin. Such a supplement post-workout would be most effective in increasing muscle protein synthesis, resulting in greater muscle hypertrophy and strength. In contrast, the consumption of essential amino acids and dextrose appears to be most effective at evoking protein synthesis prior to rather than following resistance exercise. To further enhance muscle hypertrophy and strength, a resistance weight- training program of at least 10-12 weeks with compound movements for both upper and lower body exercises should be followed.

Effects of wearing a cooling vest during the warm-up on 10-km run performance.

The purpose of this study was to examine whether wearing a cooling vest during an active warm-up would improve the 10-km time trial (TT) performance of endurance runners. Seven male runners completed 3 10-km TTs (1 familiarization and 2 experimental) on a treadmill after a 30-minute warm-up. During the warm-up of the experimental TTs, runners wore either a t-shirt (control [C]) or a cooling vest (V), the order of which was randomized. No differences were found between the C and V conditions for the 10-km TT times (2,533 ± 144 and 2,543 ± 149 seconds, respectively) (p = 0.746) or any of the 2-km split times. Heart rate (HR) at the start of the TT equaled 90 ± 17 b·min for C and 94 ± 16 b·min for V. The HR peaked at 184 ± 20 b·min in C and 181 ± 19 b·min in V. At the start of the TT Tc was 37.65 ± .72°C in C and 37.29 ± .73°C in V (p = 0.067). In C, Tc gradually increased until 39.34 ± 0.43°C while in V is reached 39.18 ± 0.72°C (p = 0.621). Although rating of perceived exertion (RPE) and Thermal sensation (TS) increased during both experimental TTs, there were no differences between V and C. Findings suggest wearing a cooling vest during a warm-up does not improve 10-km performance. The use of cooling vests during the warm-up did not produce any physiological (HR and Tc) or psychological (RPE and TS) benefit, perhaps accounting for the lack of improvement.

Effect of beta-alanine supplementation on the onset of blood lactate accumulation (OBLA) during treadmill running: Pre/post 2 treatment experimental design.

BACKGROUND: beta-Alanine (betaA) has been shown to improve performance during cycling. This study was the first to examine the effects of betaA supplementation on the onset of blood lactate accumulation (OBLA) during incremental treadmill running. METHODS: Seventeen recreationally-active men (mean +/- SE 24.9 +/- 4.7 yrs, 180.6 +/- 8.9 cm, 79.25 +/- 9.0 kg) participated in this randomized, double-blind, placebo-controlled pre/post test 2-treatment experimental design. Subjects participated in two incremental treadmill tests before and after 28 days of supplementation with either betaA (6.0 g.d-1)(betaA, n = 8) or an equivalent dose of Maltodextrin as the Placebo (PL, n = 9). Heart rate, percent heart rate maximum (%HRmax), %VO2max@OBLA (4.0 mmol.L-1 blood lactate concentration) and VO2max (L.min-1) were determined for each treadmill test. Friedman test was used to determine within group differences; and Mann-Whitney was used to determine between group differences for pre and post values (p < 0.05). RESULTS: The betaA group experienced a significant rightward shift in HR@OBLA beats.min-1 (p < 0.01) pre/post (161.6 +/- 19.2 to 173.6 +/- 9.9) but remained unchanged in the PL group (166.8 +/- 15.8 to 169.6 +/- 16.1). The %HRmax@OBLA increased (p < 0.05) pre/post in the betaA group (83.0% +/- 9.7 to 88.6% +/- 3.7) versus no change in the PL group (86.3 +/- % 4.8 to 87.9% +/- 7.2). The %VO2max@OBLA increased (p < 0.05) in the betaA group pre/post (69.1 +/- 11.0 to 75.6 +/- 10.7) but remained unchanged in the PL group (73.3 +/- 7.3 to 74.3 +/- 7.3). VO2max (L.min-1) decreased (p < 0.01) in the betaA group pre/post (4.57 +/- 0.8 to 4.31 +/- 0.8) versus no change in the PL group (4.04 +/- 0.7 to 4.18 +/- 0.8). Body mass kg increased (p < 0.05) in the betaA group pre/post (77.9 +/- 9.0 to 78.3 +/- 9.3) while the PL group was unchanged (80.6 +/- 9.1 to 80.4 +/- 9.0). CONCLUSIONS: betaA supplementation for 28 days enhanced sub-maximal endurance performance by delaying OBLA. However, betaA supplemented individuals had a reduced aerobic capacity as evidenced by the decrease in VO2max values post supplementation.

Protein supplement users among high school athletes have misconceptions about effectiveness.

Protein supplements commonly are ingested by athletes to improve strength, agility, and speed. While athletes require a higher amount of protein (g.kg body weight) than nonathletes do to support protein synthesis, they do not necessarily need to consume protein from supplemental sources. To date, no studies have shown an advantage of ingesting protein supplements over natural, protein-containing foods; therefore, dietary sources of protein may be just as effective as protein supplemental sources in the regulation of muscle protein synthesis. Misconceptions regarding protein supplement effectiveness may originate from athletes' nutrition information sources. A survey questionnaire queried high school football players about sources of information and measured protein supplement misconceptions by using scores on a Protein Supplement Misconceptions Index. Sixty-one high school football players participated in the study; 39 were protein supplementers, and 22 were non-protein supplementers. There was a significant difference between index scores of protein supplementers and non-protein supplementers (t = -3.4, p = 0.001), indicating that protein supplementers had a greater level of misconceptions than non-protein supplementers did. Bonferroni post hoc procedures used with individual index items revealed that protein supplementers were more likely than non-protein supplementers to agree that "athletes should take protein supplements" (p = 0.001) and needed them "to gain as much muscle as possible" (p = 0.001). Greater misconceptions for protein supplementers may have resulted from the sources chosen for information and advice. Since coaches, parents, and friends were the primary sources of advice about protein supplements for protein supplementers, it would be valuable to provide nutrition education to these groups concurrently with educating young athletes to dispel ongoing misconceptions regarding the need for and effectiveness of protein supplements.

Long-haul truck drivers want healthful meal options at truck-stop restaurants.

Long-haul truckers are confined, by parking regulations and other constraints, to dining at truck-stop restaurants. Objectives were to (a) compare truckers' anthropometrics with recommended guidelines; and (b) assess eating/exercise habits, importance of healthful food choices, and attitudes about restaurants' provision of healthful options. Hypotheses were: (a) overweight/obese drivers will place less importance on healthful food choices than will drivers of optimal weight; (b) importance of healthful food choices and attitudes about their provision will be positively correlated. Questionnaires included Food Choices Index, Nutrition Attitude Survey, and demographic information; bioelectrical impedance assessed weight, body fat, and body mass index. Subjects (n=92) were truckers at a Midwestern truck-stop restaurant; 79 were overweight, 52 were obese. Mean rating of importance of healthful choices was above average. There was no difference in importance of healthful food choices for overweight/obese and optimal weight drivers, t(89)=-1.312; P=0.19. Drivers placing more importance on healthful food choices had more positive attitudes about restaurants' provision of such options, r(90)=0.74, P<0.001. Overall, drivers indicated they would choose healthful foods if available and appetizing. Registered dietitian-directed wellness programs that include education, support, and cooperation of truck-stop restaurants are critical to reduce obesity and risk of disease in this population.

Preliminary study: soy milk as effective as skim milk in promoting weight loss.

Calcium from dairy sources is beneficial to weight loss; however, no studies have compared the effects of dairy to nondairy sources of calcium on weight loss. This pilot study explored differences between soy and skim milk on changes in anthropometric values in premenopausal women. In a prospective randomized controlled trial, 14 women with overweight/obesity were randomly assigned to 720 mL soy milk (n=7) or an equivalent volume of skim milk (n=7) daily for 8 weeks. Subjects followed a 500-kcal deficit diet based on metabolic rate data. There were no anthropometric differences between soy and skim milk groups at baseline. Subjects followed an energy-restricted diet; both groups experienced reductions in kilogram weight (4.27+/-2.05 vs 3.76+/-2.25; P=0.668), body fat percent (1.30+/-1.37 vs 1.87+/-1.45; P=0.464), and abdominal circumference (11.28+/-5.23 vs 8.66+/-2.51; P=0.259) while attenuating losses of fat-free mass (1.12+/-1.29 vs 0.43+/-1.12; P=0.299) during the 8-week study. There were no significant differences in weight, fat percent, abdominal circumference, and fat-free mass between groups. To optimize the weight loss effects of calcium, one can consume 720 mL of either soy milk or skim milk daily.

Effect of a defined lacto-ovo-vegetarian diet and oral creatine monohydrate supplementation on plasma creatine concentration.

This study examined the effects that preceding creatine supplementation with a lacto-ovo-vegetarian diet would have on plasma creatine concentration. Twenty-six healthy moderately fit omnivorous men were assigned to either a 26-day lacto-ovo-vegetarian (LOV; n = 12) or omnivorous (Omni; n = 14) diet. On day 22, subjects were also assigned in a double-blind manner either creatine monohydrate (CM; 0.3 g.kg(-1).day(-1) + 20 g Polycose) or an equivalent dose of placebo (PL) for 5 days. Blood samples were taken on days 1, 22 and 27. Consuming a LOV diet for 21 days was effective in reducing plasma creatine concentration (p < 0.01) in the LOV group. Regardless of diet, the CM group showed an increase in plasma creatine concentrations from day 22 to 27, whereas the PL group's levels remained the same (p < 0.05). Although the LOV diet caused a deprivation effect in plasma creatine concentration relative to the Omni diet, concurrent supplementation with creatine resulted in no difference in plasma creatine concentrations between the LOV and Omni diet groups. Dietary advice should be provided to LOV athletes that supplementation with creatine may help to increase their muscle stores of creatine, and thus their ATP resynthesis capabilities, to levels similar to those of omnivores.

Elderly herbal supplement users less satisfied with medical care than nonusers.

The purpose of the study was to examine differences between elderly herbal supplement users and nonusers with respect to their perceptions of the safety of supplements and their satisfaction with current medical care. The researchers interviewed 69 elderly persons from congregate meal sites in four Illinois counties to assess herbal supplement use, perceptions of herbal supplement safety, medical supervision of herbal supplement use, and satisfaction with medical care. Two-sample Kolmogorov-Smirnov tests compared both perceived safety of herbal supplements and satisfaction with medical care of supplement users and nonusers. Herbal supplement users were more likely to perceive supplements as safe and to be less satisfied with conventional medical care than nonusers. Some elderly persons do not inform physicians that they are using herbal supplements, thus increasing the risk for supplement misuse, toxicity, and drug-supplement interactions. It is important that physicians, dietetics professionals, and pharmacists inquire about and discuss herbal supplement use with elderly patients.

Effect of creatine supplementation and a lacto-ovo-vegetarian diet on muscle creatine concentration.

The purpose of this investigation was to examine the effects of preceding oral creatine monohydrate with a lacto-ovo-vegetarian diet on muscle creatine concentration. Thirty-two healthy men, who regularly consumed an omnivorous diet, were randomly assigned to consume a weight maintaining, lacto-ovo-vegetarian (LOV; n = 16) or omnivorous (Omni; n = 16) diet for 26 days. In addition to their assigned diet, on day 22 of the study, subjects were assigned in a double-blind manner to receive either creatine monohydrate (CM; 0.3 g kg d 1 + 20 g Polycose) or an equivalent dose of placebo (PL) for 5 days. There were no significant differences between the LOV and Omni groups at baseline with respect to age, height, and weight. The results demonstrated that consuming a LOV diet for 21 days was an effective procedure to decrease muscle creatine concentration (p <.01) in individuals who normally consume meat and fish in their diet. However, muscle total creatine (TCr) following creatine supplementation did not differ statistically between LOV and Omni diet groups (148.6 4.5 vs. 141.7 4.5 mmol kg-1 d.m.).