International society of sports nutrition position stand: caffeine and performance

Background

We compared Glycine Propionyl-L-Carnitine (GlycoCarn^®) and three different pre-workout nutritional supplements on measures of skeletal muscle oxygen saturation (StO₂), blood nitrate/nitrite (NOx), lactate (HLa), malondialdehyde (MDA), and exercise performance in men.

Methods

Using a randomized, double-blind, cross-over design, 19 resistance trained men performed tests of muscular power (bench press throws) and endurance (10 sets of bench press to muscular failure). A placebo, GlycoCarn^®, or one of three dietary supplements (SUPP1, SUPP2, SUPP3) was consumed prior to exercise, with one week separating conditions. Blood was collected before receiving the condition and immediately after exercise. StO₂ was measured during the endurance test using Near Infrared Spectroscopy. Heart rate (HR) and rating of perceived exertion (RPE) were determined at the end of each set.

Results

A condition effect was noted for StO₂ at the start of exercise (p = 0.02), with GlycoCarn^® higher than SUPP2. A condition effect was also noted for StO₂ at the end of exercise (p = 0.003), with SUPP1 lower than all other conditions. No statistically significant interaction, condition, or time effects were noted for NOx or MDA (p > 0.05); however, MDA decreased 13.7% with GlycoCarn^® and increased in all other conditions. Only a time effect was noted for HLa (p < 0.0001), with values increasing from pre- to post-exercise. No effects were noted for HR, RPE, or for any exercise performance variables (p > 0.05); however, GlycoCarn^® resulted in a statistically insignificant greater total volume load compared to the placebo (3.3%), SUPP1 (4.2%), SUPP2 (2.5%), and SUPP3 (4.6%).

Conclusion

None of the products tested resulted in favorable changes in our chosen outcome measures, with the exception of GlycoCarn^® in terms of higher StO₂ at the start of exercise. GlycoCarn^® resulted in a 13.7% decrease in MDA from pre- to post-exercise and yielded a non-significant but greater total volume load compared to all other conditions. These data indicate that 1) a single ingredient (GlycoCarn^®) can provide similar practical benefit than finished products containing multiple ingredients, and 2) while we do not have data in relation to post-exercise recovery parameters, the tested products are ineffective in terms of increasing blood flow and improving acute upper body exercise performance.     

Changes in newcomer job satisfaction over time: Examining the pattern of honeymoons and hangovers.

In this study, the authors contribute insight into the temporal nature of work attitudes, examining how job satisfaction changes across the 1st year of employment for a sample of organizational newcomers. The authors examined factors related to job change (i.e., voluntary turnover, prior job satisfaction) and newcomer experiences (i.e., fulfillment of commitments, extent of socialization) that may strengthen or weaken the job satisfaction pattern. Results of a study of 132 newcomers with data collected at 4 unique time periods show a complex curvilinear pattern of job satisfaction, such that satisfaction reached a peak following organizational entry and decreased thereafter. However, examination of moderating factors revealed that individuals who reported less satisfaction with their prior job and those having more positive experiences on the new job, such as greater fulfilled commitments and a higher degree of socialization, were most likely to experience this pattern. Findings from this study offer important implications for theory and research on changes in newcomer attitudes over time as well as practical insight on key factors that shape the pattern of job attitudes as individuals enter and experience a new workplace. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Risk perceptions: Assessment and relationship to influenza vaccination.

Objective: Accurate measurement of beliefs about risk probability is essential to determine what role these beliefs have in health behavior. This study investigated the ability of several types of risk perception measures and of other constructs from health behavior theories to predict influenza vaccination. Design: Prospective study in which students, faculty, and staff at 3 universities (N = 428) were interviewed in the fall, before influenza vaccine was available, and again early in the next calendar year. Main Outcome Measure: Self-reported influenza vaccination. Results: Two interview questions that asked about feeling at risk and feeling vulnerable predicted subsequent behavior better (r = .44, p = .001) than 2 questions that asked for agreement or disagreement with statements about risk probability (r = .25, p = .001) or 4 questions that asked respondents to estimate the magnitude of the risk probability (r = .30, p = .001). Of the 4 perceived risk magnitude scales, a 7-point verbal scale was the best predictor of behavior. Anticipated regret was the strongest predictor of vaccination (r = .45, p = .001) of all constructs studied, including risk perceptions, worry, and perceived vaccine effectiveness. Conclusion: Risk perceptions predicted subsequent vaccination. However, perceived risk phrased in terms of feelings rather than as a purely cognitive probability judgment predicted better. Because neither feeling at risk nor anticipated regret is represented in the most commonly used theories of health behavior, the data suggest that these theories are missing important constructs. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Division of Labor and Working-Class Women's Well-Being Across the Transition to Parenthood.

This study examines the degree to which the division of household and child-care tasks predicts working-class women's well-being across the transition to parenthood. Women completed questionnaires about the division of labor and their well-being before the birth of their first child and upon returning to work. Results showed that violated expectations regarding the division of child care were associated with increased distress postnatally, and there was some evidence that this relationship was moderated by gender ideology. Traditional women whose husbands did more child care than they expected them to do were more distressed. Work status also moderated the relationship between violated expectations and distress. The results suggest that the division of child care is more salient in predicting distress than the division of housework, for working-class women, at this time point. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Perceived parenting skill across the transition to adoptive parenthood among lesbian, gay, and heterosexual couples.

Little research has examined change in perceived parenting skill across the transition to parenthood or predictors of change in perceived skill. The current study used an ecological framework to examine predictors of self-perceived parenting skill among 47 lesbian, 31 gay, and 56 heterosexual couples who were adopting their first child. Findings revealed that, on average, all new parents perceived themselves as becoming more skilled, although gay men increased the most and lesbians the least. Participants who were female, reported fewer depressive symptoms, expected to do more child care, and reported higher job autonomy viewed themselves as more skilled pre-adoption. With regard to change, parents who reported more relational conflict and parents who expected to do more child care experienced lesser increases in perceived skill. These findings suggest that regardless of gender, sexual orientation, and route to parenthood, new parents experience similar, positive changes in perceived skill, thereby broadening our understanding of parenting skill in diverse groups. The findings also highlight the importance of examining how gender, sexual orientation, and the family context may shape perceived skill across the transition to parenthood. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effects of creatine loading on electromyographic fatigue threshold during cycle ergometry in college-aged women

The purpose of this study was to examine the effects of 5 days of Creatine (Cr) loading on the electromyographic fatigue threshold (EMG_FT) in college-aged women. Fifteen healthy college-aged women (mean ± SD = 22.3 ± 1.7 yrs) volunteered to participate in this double-blind, placebo-controlled study and were randomly placed into either placebo (PL – 10 g of flavored dextrose powder; n = 8) or creatine (Cr – 5 g di-creatine citrate plus 10 g of flavored dextrose powder; n = 7; Creatine Edge, FSI Nutrition) loading groups. Each group ingested one packet 4 times per day (total of 20 g/day) for 5 days. Prior to and following supplementation, each subject performed a discontinuous incremental cycle ergometer test to determine their EMG_FT value, using bipolar surface electrodes placed on the longitudinal axis of the right vastus lateralis. Subjects completed a total of four, 60 second work bouts (ranging from 100–350 W). The EMG amplitude was averaged over 10 second intervals and plotted over the 60 second work bout. The resulting slopes from each successive work bouts were used to calculate EMG_FT. A two-way ANOVA (group [Cr vs. PL] × time [pre vs. post]) resulted in a significant (p = 0.031) interaction. Furthermore, a dependent samples t-test showed a 14.5% ± 3.5% increase in EMG_FT from pre- to post-supplementation with Cr (p = 0.009), but no change for the PL treatment (-2.2 ± 5.8%; p = 0.732). In addition, a significant increase (1.0 ± 0.34 kg; p = 0.049) in weight (kg) was observed in the Cr group but no change for PL (-0.2 kg ± 0.2 kg). These findings suggest that 5 days of Cr loading in women may be an effective strategy for delaying the onset of neuromuscular fatigue during cycle ergometry.     

Experiment archive,analysis, and visualization at the National Ignition Facility

The National Ignition Facility (NIF) at the Lawrence Livermore National Laboratory is the world's most energetic laser, providing a scientific research center to study inertial confinement fusion and matter at extreme energy densities and pressures. A target shot involves over 30 specialized diagnostics measuring critical x-ray, optical and nuclear phenomena to quantify ignition results for comparison with computational models. The Shot Analysis and Visualization System (SAVI) acquires and analyzes target diagnostic data for display within a time-budget of 30 min. Laser and target diagnostic data are automatically loaded into the NIF archive database through clustered software data collection agents. The SAVI Analysis Engine distributes signal and image processing tasks to a Linux cluster where computation is performed. Intermediate results are archived at each step of the analysis pipeline. Data is archived with metadata and pedigree. Experiment results are visualized through a web-based user interface in interactive dashboards tailored to single or multiple shot perspectives. The SAVI system integrates open-source software, commercial workflow tools, relational database and messaging technologies into a service-oriented and distributed software architecture that is highly parallel, scalable, and flexible. The architecture and functionality of the SAVI system will be presented along with examples.