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Purpose: To investigate the placebo effect of caffeine on pacing strategy and performance over 1000-m running time trials using a balanced placebo design. Methods: Eleven well-trained male middle-distance athletes performed seven 1000-m time trials (1 familiarization, 2 baseline, and 4 experimental). Experimental trials consisted of the administration of 4 randomized treatments: informed caffeine/received caffeine, informed caffeine/received placebo, informed placebo/received caffeine, and informed placebo/received placebo. Split times were recorded at 200, 400, 600, 800, and 1000 m, and peak heart rate and rating of perceived exertion were recorded at the completion of the trial. Results: Relative to baseline, participants ran faster during informed caffeine/received caffeine (d = 0.42) and informed caffeine/received placebo (d = 0.43). These changes were associated with an increased pace during the first half of the trial. No differences were shown in pacing or performance between baseline and the informed placebo/received caffeine (d = 0.21) and informed placebo/received placebo (d = 0.10). No differences were reported between treatments for peak heart rate (η2 =.084) and rating of perceived exertion (η2 =.009). Conclusions: The results indicate that the effect of believing to have ingested caffeine improved performance to the same magnitude as actually receiving caffeine. These improvements were associated with an increase in pace during the first half of the time trial. [ABSTRACT FROM AUTHOR]

In the present study, our team aimed to investigate the effects of acute ingestion of a ketone salt (KS) supplement on the cognitive performance in healthy college-aged males during a dual-stress challenge (DSC). Following a peak oxygen uptake test and DSC familiarization, 16 males completed a DSC while cycling at 60% of their respective peak oxygen uptake after ingesting either a commercially available racemic (D- and L-)β-hydroxybutyrate (β-OHB) KS (0.38 g/kg body mass) or a placebo, using a triple-blinded, crossover, and counterbalanced design. The participants consumed the KS or placebo at −60 and −15 min prior to the start of the DSC. Heart rate, rating of perceived exertion, and blood β-OHB and glucose were sampled throughout. The DSC consisted of a mental arithmetic challenge and a modified Stroop Color Word, which alternated every 2 min for 20 min. Upon completion of the DSC, responses for correct, incorrect, and no responses were recorded for the mental arithmetic challenge and Stroop Color Word. Blood β-OHB was elevated with KS by −15 min and remained so throughout (p <.001), peaking at 0.76 ± 0.32 mM. Blood glucose was lower with KS compared with the placebo at −15 and 10 min by 9% and 5%, respectively (both ps <.05). There were no differences between the treatments for heart rate, rating of perceived exertion, mental arithmetic challenge, or Stroop Color Word. Overall, this study suggests that KSs are not effective aids for enhancing cognitive performance during a DSC, which might partially be explained by the inability of currently available commercial KS supplements to elevate β-OHB blood concentrations above ∼1.0 mM. [ABSTRACT FROM AUTHOR]

Background Low energy availability (LEA) can have negative performance consequences, but the relationships between LEA and performance are poorly understood especially in field conditions. In addition, little is known about the contribution of macronutrients to long-term performance. Therefore, the aim of this study was to evaluate if energy availability (EA) and macronutrient intake in a field-based situation were associated with laboratory-measured performance, anthropometric characteristics, blood markers, training volume, and/or questionnaire-assessed risk of LEA in young female cross-country (XC) skiers. In addition, the study aimed to clarify which factors explained performance. Methods During a one-year observational study, 23 highly trained female XC skiers and biathletes (age 17.1 ± 1.0 years) completed 3-day food and training logs on four occasions (September–October, February–March, April–May, July–August). Mean (±SD) EA and macronutrient intake from these 12 days were calculated to describe yearly overall practices. Laboratory measurements (body composition with bioimpedance, blood hormone concentrations, maximal oxygen uptake (VO2max), oxygen uptake (VO2) at 4 mmol·L−1 lactate threshold (OBLA), double poling (DP) performance (time to exhaustion), counter movement jump (height) and the Low Energy Availability in Females Questionnaire (LEAF-Q)) were completed at the beginning (August 2020, M1) and end of the study (August 2021, M2). Annual training volume between measurements was recorded using an online training diary. Results The 12-day mean EA (37.4 ± 9.1 kcal·kg FFM−1·d−1) and carbohydrate (CHO) intake (4.8 ± 0.8 g·kg−1·d−1) were suboptimal while intake of protein (1.8 ± 0.3 g·kg−1·d−1) and fat (31 ± 4 E%) were within recommended ranges. Lower EA and CHO intake were associated with a higher LEAF-Q score (r = 0.44, p = 0.042; r = 0.47, p = 0.026). Higher CHO and protein intake were associated with higher VO2max (r = 0.61, p = 0.005; r = 0.54, p = 0.014), VO2 at OBLA (r = 0.63, p = 0.003; r = 0.62, p = 0.003), and DP performance at M2 (r = 0.42, p = 0.051; r = 0.44, p = 0.039). Body fat percentage (F%) was negatively associated with CHO and protein intake (r = -0.50, p = 0.017; r = -0.66, p = 0.001). Better DP performance at M2 was explained by higher training volume (R2 = 0.24, p = 0.033) and higher relative VO2max and VO2 at OBLA at M2 by lower F% (R2 = 0.44, p = 0.004; R2 = 0.47, p = 0.003). Increase from M1 to M2 in DP performance was explained by a decrease in F% (R2 = 0.25, p = 0.029). Conclusions F%, and training volume were the most important factors explaining performance in young female XC skiers. Notably, lower F% was associated with higher macronutrient intake, suggesting that restricting nutritional intake may not be a good strategy to modify body composition in young female athletes. In addition, lower overall CHO intake and EA increased risk of LEA determined by LEAF-Q. These findings highlight the importance of adequate nutritional intake to support performance and overall health.

Background CrossFit includes weightlifting, powerlifting, and gymnastics in various combinations of overloads and repetitions with limited rest periods or no rest between training sets. Due to the novelty of CrossFit, there are few studies on the effect of nutritional strategies on the acute response to this type of sports activity. This study examined the effect of caffeine (CAF) and sodium bicarbonate (NaHCO3) ingestion separately and in combination on the performance and rate of perceived exertion (RPE) during the Cindy CrossFit workout (Cindy) in CrossFit participants. Method In a double-blind, crossover, randomized, placebo-controlled trial, 20 CrossFit participants underwent five experimental conditions, including control (CON), placebo (PLA), CAF, NaHCO3, and CAF + NaHCO3 (7 days to wash-out between assessment sessions) before completing the Cindy protocol (age: 22.30 ± 2.88 years, body mass index: 25.22 ± 2.51 kg/m2). Capsules containing 6 mg/kg body weight (BW) CAF were consumed 50 min before the Cindy workout while 0.3 g/kg BW NaHCO3 was consumed for 3 days, leading to 120, 90, and 60 min before the Cindy workout. Performance, RPE, muscular power (MP), handgrip strength (HGS), and maximum heart rate (MHR) were measured before and shortly after the Cindy. Results The performance of CrossFit participants during the Cindy protocol was not significantly improved following CAF, NaHCO3, and CAF + NaHCO3 (P > 0.05). In contrast, RPE during and at the end of the Cindy was significantly decreased following CAF + NaHCO3 consumption compared to PLA and CON (P = 0.001, P = 0.02). However, MP (P = 0.82) and HGS (P = 0.52) were not significantly different between conditions. Also, MHR was significantly greater following CAF, NaHCO3, and CAF + NaHCO3 consumption than CON (P = 0.01). Conclusion CAF + NaHCO3 supplementation decreased RPE despite significantly increased MHR, but with no significant effect on performance, HGS, or MP. Therefore, CrossFit participants may benefit from the ergogenic effects of CAF and NaHCO3 when consumed separately or together.

The American College of Sports (ACSM.org) is a professional organization for sport science researchers, educators, exercise physiologists, sports dietitians, and doctors. At ACSM's Annual Meeting (May 2024, Boston), more than [...]

Although tyrosine supplementation is well recognized to improve cognitive function, its impact on endurance performance is debatable and needs to be clarified further. The purpose of this systematic review and meta-analysis was to evaluate the effects of tyrosine supplementation on whole-body endurance performance in physically active population. The search strategy follow the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA), using four databases (Cochrane Library, Web of Science, Scopus, PsycINFO, and PubMed) until 3 August 2023. The effect of tyrosine (experimental condition) was compared against placebo (control condition). The methodological quality of the included studies was evaluated using the Physiotherapy Evidence Database (PEDro) scale. The Grading of Recommendations Assessment, Development, and Evaluation (GRADE Pro software) System was also used to assess the quality of evidence. A total of 10 interventions from 8 studies were included. The sub-group analysis revealed no significant differences between tyrosine and placebo conditions for time to exhaustion (SMD = 0.02; p = 0.94) and time trial performance (SMD = -0.04; p = 0.85). The level of evidence as qualified with GRADE was moderate. In conclusion, moderate-quality evidence suggests that tyrosine supplementation is ineffective on endurance performance in the physically active population, independently of the endurance task (TTE or ETT). [ABSTRACT FROM AUTHOR]

The most common sports nutrition strategies were constructed not only for maximizing musculoskeletal adaptations to exercise, but also to minimize health risks in athletes. Given the lack of research highlighting the potential effects of the intake of carbohydrates, fats, and B vitamins on body fat percentage in a population of female athletes, this study aimed to elucidate whether the intake of macronutrients and B vitamins could be associated with the variation in body fat percentage in a cohort of professional female athletes. This cross-sectional study was weighted to represent Lithuanian elite female athletes (n = 89). The dietary assessment of the female athletes was carried out using a 3-day dietary recall method. Their body composition was assessed using the bioelectrical impedance analysis method. For females, the reported average intakes of energy, carbohydrates, protein, and fat were 2475 kcal/day, 5.1 g/kg/day, 1.5 g/kg/day, and 36.7%, respectively. Excess B vitamin intake was revealed, ranging within plus 1–2 standard deviations (SDs) around the mean requirements. As a consequence, excessive body fat percentage was potentially factored as a negative outcome in maintaining optimal body composition in female athletes. Multivariate logistic regression analysis of a sample of female athletes revealed that, despite a slightly positive energy balance (∆ 95 kcal/day), the carbohydrate-deficient diet (adjusted odds ratio (aOR) 0.3, 95% confidence interval (CI) 0.1; 0.7), along with higher intakes of vitamin B1 (aOR 2.9, 95% CI 2.6; 7.8), vitamin B2 (aOR 6.7, 95% CI 1.1; 8.3), and vitamin B3 (aOR 1.8, 95% CI 1.4; 7.8) from food, was associated with a lower percentage of body fat. Therefore, more attention should be given to the intake of B vitamins in professional athletes with a range of body fat mass percentages for the purpose of achieving long-term goals of maintaining body composition and fitness. [ABSTRACT FROM AUTHOR]

Research and market data have shown a growing demand for sports supplements and increasing consumers' awareness regarding their health and environmental attributes. An extended Theory of Planned Behavior (TPB) framework was tested to explain insect-based protein bars and powder consumption among 256 Brazilians who are gym users and consume conventional sports supplements and results were analyzed using PLS-SEM. Perceived risk outperformed attitude as a predictor, diminishing the intention to consume insect-based sports supplements. Health proved to be the most important explanatory factor of attitude, while sustainability resulted in a smaller effect and taste impact was not significant. Whereas media was significant and a relatively strong predictor of the subjective norm, experts were not. Media content, such as social media, receives more attention and the information that gym users value is not predominantly provided by health professionals in the case of muscle-building products. Policymakers, marketing professionals, consumer psychology and product development can also benefit from the results to provide clear and accessible information about supplements across all sporting communities to reduce risk perception and increase acceptance. [ABSTRACT FROM AUTHOR]

In the pursuit of enhanced athletic prowess in different disciplines, athletes constantly look for strategies to increase their physical performance, encompassing technical skills and dietary components, which inevitably, in most cases, include the incorporation of sports supplements. In recent years, there has been an increase in the number of athletes using ergogenic aids. In this context, scientific evidence must play a prominent role in either endorsing or warning against the use of these products, ensuring the preservation of health while promoting the theoretically established positive benefits. In this vein, beetroot juice (BJ) stands out as a key supplement as an ergogenic aid to improve sports performance, given its demonstrated influence on both aerobic and anaerobic exercise. However, despite widespread global demand, there remains a lack of understanding regarding the potential synergistic effects of combining BJ with other supplements. Consequently, our study aims to determine whether the combination of BJ with another nutritional supplement can enhance its beneficial effects and, therefore, optimize physical performance in humans. A comprehensive literature search was conducted in two major databases—Web of Science and PubMed—from 1 January 2018 to 29 January 2023, using specific keywords. After the exclusion criteria, six articles were selected for analysis. Therefore, our study shows that the effectiveness of combining BJ with another supplement mainly depends on the duration of the chronic intervention, which is where the greatest benefits have been observed. [ABSTRACT FROM AUTHOR]

Vitamin D is crucial to the health and performance of athletes. Although the exact vitamin D requirements for athletes have not been established, maintaining a 25(OH)D level of at least 40 ng/mL is considered beneficial. This randomized controlled intervention study aimed to determine whether an individual loading dose formula for vitamin D supplementation is more effective than standardized supplementation and suitable enough for athletes to meet a target value of 40 ng/mL. In a 10-week supplementation study conducted during the winter months in Germany, 90 athletes with insufficient vitamin D levels (25(OH)D < 30 ng/mL) were randomly assigned to receive either a universal dose of 2000 IU/day of vitamin D or a loading dose of 4000 IU/day, followed by a maintenance dose of 1000 IU/day. The total 25(OH)D concentration was measured from dried blood spots at three time points: at baseline, at the computed date of 40 ng/mL, and after the 10-week period. Additionally, a vitamin-D-specific questionnaire was issued. On the day when 25(OH)D blood concentrations of 40 ng/mL were calculated to prevail, the individualized group had a significantly higher 25(OH)D level than the standardized group (41.1 ± 10.9 ng/mL vs. 32.5 ± 6.4 ng/mL, p < 0.001). This study demonstrated that the examined formula is suitable enough for athletes to achieve a 25(OH)D concentration of 40 ng/mL. This indicates that a personalized approach is more effective than a one-size-fits-all approach in restoring adequate vitamin D levels in athletes. [ABSTRACT FROM AUTHOR]

Background: Athletes should be informed of their required energy intake in preparation for sports competitions. However, the environment in which dietary surveys can be conducted to determine the required energy intake for sports competitions is limited, and such survey will require a substantial amount of time and effort from athletes and dietitians. If certain biomarkers for estimating the energy intake can be identified, they may compensate for the shortcomings of these dietary surveys. We aimed to identify the blood biomarkers to estimate the energy intake/basal metabolic rate ratio of male athletes. Methods: Twenty-six male athletes from a university physical education department were included and underwent measurements of height, weight, and body composition, as well as blood sampling. The dietary assessment included a 3-day dietary recall and collection of meal photographs. The basal metabolic rate was estimated using the lean body mass, while the daily energy intake/basal metabolic rate ratio was used as an index to determine the energy intake. From the 36 selected blood biomarkers, we identified the independent biomarkers for inclusion in the multiple regression analysis by assessing for pairwise correlations and multicollinearity. A formula for estimating the energy intake/basal metabolic rate was then developed using the stepwise method. A p-value of < 0.05 was considered significant. Results: Overall, 18 of the 36 blood biomarkers were selected, and multiple regression analysis revealed that triiodothyronine, white blood cell count, and triglyceride level were significant factors that can be used to estimate the energy intake/basal metabolic rate, accounting for 60.4% of the variance. No systematic errors were observed in the estimated values, calculated using the estimation formula and dietary assessment results. Conclusions: A combination of free triiodothyronine level, white blood cell count, and triglyceride level can be used for estimating the energy intake/basal metabolic rate of male athletes, thus compensating for the shortcomings of dietary surveys. [ABSTRACT FROM AUTHOR]

Perfectionism is associated with sleep as well as with academic and sports performance. Given the importance of sleep for performance and the sleep changes that occur during adolescence, the present study aimed to explore the relationship between sleep, two dimensions of perfectionism (perfectionistic strivings and perfectionistic concerns), with academic and sports performance in young athletes. The occurrence of perfectionistic strivings was identified as a tendency to set high personal standards for oneself, while the occurrence of perfectionistic concerns was identified as a tendency to feel pressure to be perfect and have concerns about imperfections. A total of 32 athletes aged 13 to 16 years old participated in this study. Perfectionism, sleep, and course grades were measured at the end of the school year. Sleep was measured by actigraphy, and sports performance improvement was obtained by comparing individual performance at the beginning and the end of the school year. The moderating effect of both dimensions of perfectionism on the relationships between sleep and academic and sports performance improvement was measured. First, results showed no significant relationship between sleep and academic/sports performance. Further analyses revealed that perfectionistic strivings moderated the relationship between certain aspects of sleep with academic and sports performance improvement. Delayed and suboptimal sleep habits were associated with lower academic and sports performance improvement when low levels of perfectionistic strivings were present. Results with perfectionistic concerns showed that this dimension did not moderate the relationship between sleep and academic and sports performance improvement. This study supports the notion that high levels of perfectionistic strivings in young athletes may mitigate the adverse effects of poor sleep habits in young athletes. [ABSTRACT FROM AUTHOR]

Force-based human posture estimation (FPE) provides a valuable alternative when camera-based human motion capturing is impractical. It offers new opportunities for sensor integration in smart products for patient monitoring, ergonomic optimization and sports science. Due to the interdisciplinary research on the topic, an overview of existing methods and the required expertise for their utilization is lacking. This paper presents a systematic review by the PRISMA 2020 review process. In total, 82 studies are selected (59 machine learning (ML)-based and 23 digital human model (DHM)-based posture estimation methods). The ML-based methods use input data from hardware sensors—mostly pressure mapping sensors—and trained ML models for estimating human posture. The ML-based human posture estimation algorithms mostly reach an accuracy above 90%. DHMs, which represent the structure and kinematics of the human body, adjust posture to minimize physical stress. The required expert knowledge for the utilization of these methods and their resulting benefits are analyzed and discussed. DHM-based methods have shown their general applicability without the need for application-specific training but require expertise in human physiology. ML-based methods can be used with less domain-specific expertise, but an application-specific training of these models is necessary. [ABSTRACT FROM AUTHOR]

This study aimed to determine whether the fat and protein content in dairy‐fruit blends prepared using full‐fat, semi‐skimmed, skimmed or high‐protein milk in combination with freeze‐dried blackberry puree influenced the bioaccessibility and bioavailability of blackberry polyphenols and organic acids. Samples were subjected to in vitro digestion, after which bioavailability was analysed with a Caco‐2 cell model. The addition of puree to milk resulted in the formation of protein aggregates, which partially protected anthocyanins during digestion. Milk fat may have increased the bioaccessibility of anthocyanins while reducing permeability through the Caco‐2 cells, leading to a lower bioavailability in tested samples. [ABSTRACT FROM AUTHOR]

The coastal waters off Peru are among the world's most productive, thanks to the Humboldt Current and its strong coastal upwelling. Fisheries and an ever-expanding mariculture sector provide millions of Peruvians livelihoods, income, and nutrition. Coastal communities engaging with these sectors face a volatile environment they have historically adapted to. But when the COVID-19 pandemic unfolded in 2020, affecting all aspects of life, challenges for the fisheries and mariculture sectors emerged to a yet unprecedented extent. This work applies a mixed-method approach for documenting and analysing the effects of the pandemic on the Peruvian seafood sector and seafood worker's economy in particular. Mobility restrictions and market closures disrupted seafood supply chains, altering access to nutrition and income for many people involved. Interviewees aimed to diversify livelihood strategies and use personal networks to withstand the crisis, while some established adaptation strategies, such as migration towards other fishing grounds, were largely impeded. Our results highlight the vulnerability of seafood value chains—mainly artisanal and small-scale fisheries—in the face of such a global crisis. The implications of the pandemic for the long-term sustainability of Peruvian coastal–marine activities are discussed and set into the context of previously experienced crises in the region. [ABSTRACT FROM AUTHOR]

Due to documented adverse events, understanding the prevalence of nutritional supplements commonly used by athletes is essential. This cross-sectional study used data from a web-based survey conducted in February-March 2022. Participants were Division I (DI) and Division III (DIII) student-athletes of the National Collegiate Athletic Association (NCAA). Chi-square tests were conducted to identify the differences in the prevalence of demographic and athletic characteristics between the divisions. Multivariable odds ratios and 95% confidence intervals were calculated using logistic regression adjusting for potential confounders to determine the predictors of supplement usage. A total of 247 NCAA student-athletes (72.5% Division I, 27.5% Division III) completed the survey, yielding a 24.5% response rate. There were no significant differences between nutritional supplementation and NCAA divisions. Instead, all student-athletes used supplements regardless of division. There were significant differences in race, ethnicity, sports dietitian access, name, image, and likeness (NIL), advisement to consume NS, and knowledge of NS between the divisions (all P-values < 0.01). Unadjusted regression models showed that being in an upper-level academic standing was associated with higher odds of using sports food and ergogenic supplements than student-athletes with a lower-level academic standing. However, multivariable logistic regression analysis revealed that none of the demographic and athletic characteristics significantly affected supplement usage. Allocating resources for access to sports dietitians and supplement education for all divisions may benefit student-athletes knowledge and safety. [ABSTRACT FROM AUTHOR]

Introduction: Limited studies have examined the dietary intake pattern of Malaysian endurance athletes. Differences in the types of foods consumed between Malaysian and Western population leads to varying nutritional intake values. This study aimed to characterise the dietary intake of Malaysian endurance athletes as compared to sports nutrition recommendations, and to determine the associations between participants' backgrounds and macronutrients intake status. Methods: A total of 85 endurance-trained Malaysian athletes participated in a cross-sectional study. Dietary intake for three days throughout the training season was evaluated using 24-hour dietary recall. The macronutrients and micronutrients intakes were compared to the nutritional recommendation for athletes and the Recommended Nutrient Intakes (RNI), respectively. The food serving size was compared to the Malaysian Food Pyramid 2020. Results: Of all participants, 51% met the minimum recommendations for carbohydrate (CHO) intake (6g/kg/day). For protein intake, 88% of participants had surpassed the lower limit of 1.2g/kg/day. The lower limit of fat intake (20% of total daily energy intake) was met by 99% of the participants. Most of the participants had a suboptimal intake of calcium, vitamin A, and vitamin E, while all had inadequate vitamin D intake. The athletes' institution was significantly associated with the CHO intake status. Also, the athletes' institution and the highest education level were significantly associated with the protein intake status. Conclusion: Athletes who practised Asian-based diets were able to achieve the energy, protein, and fat intake recommendations. However, there was a suboptimal intake of the CHO and micronutrients as compared to the recommendations. [ABSTRACT FROM AUTHOR]

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This article examines the quality and reliability of information on sports supplementation found on Instagram. The study found that the majority of posts on this topic had low scientific reliability, but the quality varied depending on the education level of the author. The most popular supplements mentioned in the posts were whey protein, creatine, caffeine, and omega 3. Nutritionists and nutrition students had higher quality posts compared to influencers and content producers. The study emphasizes the importance of being cautious when consuming and sharing information on social media platforms and highlights the need for accurate and adequate nutritional information. The list of references provides further insights into the challenges and opportunities of using social media for health communication. [Extracted from the article]